PERUPETRO SA TUMBES AND TALARA BASINS

Transcripción

PERUPETRO S. A.
TUMBES AND TALARA BASINS
HYDROCARBON EVALUATION
by
Basin Evaluations Group
Exploration Department
Elmer Martínez Senior Coordinator
Justo Fernández (Project Leader/
Senior Petroleum Geologist)
Elmer Martínez (Senior Geophysicist)
Ysabel Calderón (Geologist)
Wilber Hermoza (Structural Geologist)
Carlos Galdos (Geophysicist)
December 2005
TABLE OF CONTENTS
TABLE OF CONTENTS.............................................................................................. 1
FIGURES ..................................................................................................................... 3
TABLES ...................................................................................................................... 7
ENCLOSURES ............................................................................................................ 7
APPENDICES.............................................................................................................. 8
EXECUTIVE SUMMARY......................................................................................... 10
1.0. INTRODUCTION ............................................................................................... 12
1.1. Regional Basin Description .............................................................................. 14
1.2. Bathymetry ...................................................................................................... 15
2.0. PREVIOUS WORK IN THE STUDY AREA ...................................................... 16
2.1. Talara Basin ..................................................................................................... 16
2.2. Tumbes Basin .................................................................................................. 16
3.0. DATA GATHERING .......................................................................................... 18
3.1. Database .......................................................................................................... 18
4.0. SCOPE OF PROJECT ......................................................................................... 19
5.0. GEOLOGY OF THE TALARA AND TUMBES BASINS .................................. 21
5.1. Regional Geology ............................................................................................ 21
5.1.1. Pre-Andean System ................................................................................... 21
5.1.2. Andean System ......................................................................................... 24
5.2. Geology of the Talara and Tumbes Basins Project Area ................................... 24
5.2.1. Basement .................................................................................................. 26
5.2.2. Paleozoic................................................................................................... 26
5.2.3. Cretaceous................................................................................................. 26
5.2.4. Cenozoic ................................................................................................... 34
5.2.4.1. Tertiary............................................................................................... 34
5.2.4.2. TALARA BASIN............................................................................... 34
5.2.4.3. TUMBES BASIN............................................................................... 38
5.3. Regional Tectonics Settings ........................................................................ 39
5.3.1. Geometric and structural analyses of the Talara and Tumbes forearc basins40
5.3.1.1. Tumbes Basin ..................................................................................... 41
5.3.1.2. Talara Basin ....................................................................................... 44
5.3.1.3. Posters................................................................................................ 46
6.0. GEOPHYSICS .................................................................................................... 47
6.1. Seismic Data .................................................................................................... 47
6.2. Airmagnetometry and Air gravity..................................................................... 48
7.0. PETROLEUM GEOLOGY.................................................................................. 50
7.1.Geochemistry.................................................................................................... 50
7.1.1. General Discussion.................................................................................... 50
7.1.2. Source Rocks and Maturity ....................................................................... 51
7.1.2.1. Tertiary............................................................................................... 52
7.1.2.2. Cretaceous.......................................................................................... 53
7.1.2.3. Paleozoic ............................................................................................ 54
7.1.3. Talara Basin .............................................................................................. 54
7.1.3.1. Sample Analyses ................................................................................ 54
7.1.3.2. Hydrocarbon Analyses........................................................................ 57
7.1.3.3. Oil Families........................................................................................ 58
7.1.3.4. Oil-Oil and Oil-Source Rock Correlations .......................................... 59
7.1.3.5. Migration and Remigration of Hydrocarbons ...................................... 60
1
7.1.3.6. Hydrocarbon Kitchens ........................................................................ 60
7.1.3.7. Hydrocarbon Occurrences and Petroleum Systems ............................. 61
7.1.3.8. Reservoirs, Seals and Traps ................................................................ 62
7.1.4. Tumbes Basin............................................................................................ 62
7.1.4.1. Sample Analyses ................................................................................ 62
7.1.4.2. Hydrocarbon Analyses........................................................................ 64
7.1.4.3. Oil Families........................................................................................ 65
7.1.4.4. Migration and Remigration of Hydrocarbons ..................................... 65
7.1.4.5. Hydrocarbon Kitchens ........................................................................ 65
7.1.4.6. Hydrocarbon Occurrences and Petroleum Systems ............................. 66
7.1.4.7. Reservoirs, Seals and Traps ................................................................ 66
7.1.5. Temperature Gradient................................................................................ 67
7.2. Thermal Maturity And HC Generation Modeling. ............................................ 70
7.2.1. Introduction............................................................................................... 70
7.2.2. Data Input and Modeling ........................................................................... 70
7.2.3. Talara Basin .............................................................................................. 72
7.2.3.1. Well Lomitos 3585, Negritos Talara High .......................................... 73
7.2.3.2. Well Lomitos 3835, Negritos Talara High .......................................... 76
7.2.3.3. Well La Casita 55X, Bayovar Bay ...................................................... 78
7.2.3.4. Well SBXA, Bayovar Bay .................................................................. 82
7.2.4. Tumbes Basin............................................................................................ 84
7.2.4.1. Barracuda 15-4X Well ........................................................................ 84
7.2.4.2. Corvina 40X Well............................................................................... 86
7.2.4.3. Pseudowell 1 ...................................................................................... 88
8.0. PROSPECTS AND LEADS IN THE TALARA AND TUMBES FOREARC
BASINS ..................................................................................................................... 91
8.1. New Prospects and Leads................................................................................. 92
8.1.1. Tumbes Basin............................................................................................ 94
8.1.1.1. Atun Prospect..................................................................................... 94
8.1.1.2. Banco Peru Prospective Area.............................................................. 96
8.1.1.3. Chita Prospect .................................................................................... 99
8.1.1.4. Corvina type lead associated to Chita Prospect ..................................101
8.1.1.5. Deeper Delfin Lead ...........................................................................103
8.1.1.6. Espada Lead ......................................................................................104
8.1.1.7. Jurel Lead..........................................................................................106
8.1.1.8. Lenguado Lead..................................................................................107
8.1.1.9. Merluza Lead ....................................................................................108
8.1.1.10. Paiche Prospect................................................................................109
8.1.1.11. Perico Lead .....................................................................................110
8.1.1.12. Raya Prospect..................................................................................111
8.1.1.13. Toyo Prospect..................................................................................113
8.1.1.14. Zorritos-Piedra Redonda Lead .........................................................116
8.1.2. Talara Basin .............................................................................................116
8.1.2.1. Calamar Lead ....................................................................................117
8.1.2.2. Caballa Prospect................................................................................118
8.1.2.3. Tortuga Prospect................................................................................118
8.1.2.4. Deeper Lobitos Paleozoic Lead..........................................................120
8.1.2.5. Mero Lead.........................................................................................120
8.1.2.6. Tiburon lead ......................................................................................121
8.1.2.7. Other prospects..................................................................................122
2
8.2. Previously Defined Prospects and Leads .........................................................123
9.0. CONCLUSIONS ...........................................................................................124
9.1. General ...........................................................................................................124
9.2. Stratigraphy ....................................................................................................124
9.3. Tectonics ........................................................................................................124
9.4. Petroleum Systems and Basin Modeling..........................................................125
9.5. Prospects and Leads ........................................................................................126
10.0. SELECTED REFERENCES.............................................................................128
FIGURES
Figure 1. Location Map. NW Coastal Basins with location of the Talara and Tumbes
Basins................................................................................................................. 13
Figure 2. Stratigraphic Column of the Talara Basin. Figure modified from old IPC
files..................................................................................................................... 22
Figure 3. Stratigraphic Column of the Tumbes Basin. Figure modified from OXY
(2000)................................................................................................................. 23
Figure 4: Location Map of Cross Sections in The Talara and Tumbes Basins.
Enclosures 2....................................................................................................... 25
Figure 5. Paleozoic and Cretaceous in well EA 1875 in the Laguna Oil Field.......... 27
Figure 6. Paleozoic and Cretaceous in well EA 2114-P in the Laguna Oil Field...... 28
Figure 9. Paleozoic and Cretaceous in well EA 2323-E in the Laguna Oil Field...... 31
Figure 10. Stratigraphic relationship in formations of early Tertiary age in the Talara
Basin. ................................................................................................................. 37
Figure 11: Morphological and structural configuration in the Andean Cordillera,
showing the Talara and Tumbes forearc basins. ............................................... 40
Figure 12. Geological and structural map of the onshore portions of the Tumbes and
Talara basins and adjacent areas, showing the location of interpreted seismic
lines in red and regional cross sections, referred to in this chapter. .................. 41
Figure 13. Structural map of the Tumbes basin and northern part of the Talara
basin. For more details see Appendix 3 and Enclosure 3m................................ 42
Figure 14. Seismic interpretation of the line PC 99-01, showing the gravitational
structures associated with the Corvina and Barracuda structures. In the Corvina
structure note, the importance of the rock units subcropping the base of the
Cardalitos unconformity with respect to hydrocarbon exploration. More details
can be found in Appendix 3 and Enclosure 3a. ................................................. 42
Figure 15. Seismic interpretation of the line AIP 92-49, showing the Delfin structure
with its deeper Lead and the Lenguado lead. More details can be found in
Appendix 3 and Enclosure 3c. ........................................................................... 43
Figure 16. Seismic interpretation of the regional seismic line RIB 93-01, showing the
main tectonic elements of the Tumbes Basin. The Banco Peru is on the left and
the Tumbes Basin on the right. This seismic interpretation shows two potential
prospective structures, the Chita and Paleozoic Banco Peru leads. More details
can be found in Appendix 3 and Enclosure 3c................................................... 43
Figure 17. Seismic interpretation of the line AIP 92-30, showing the Zorritos Piedra
Redonda High to the right, the Deep Piedra Redonda Lead associated with the
Eocene series and the Perico and Raya leads to the left. According to the
structural and seismic interpretation, the Zorritos – Piedra Redonda High is part
3
of a present-day SW- NE horst structure. The western flank (offshore) of this
feature is defined by the SW-NE trending Tumbes and Piedra Redonda normal
listric faults. The eastern flank (onshore) of this structure is defined by the SWNE trending Tronco Mocho, Cardalitos and Carpitas normal fault system, which
dips to the SE. This fault system is related to the ancient structural configuration
of the Paleogene Talara basin that was reactivated during the Neogene........... 43
Figure 18. Seismic interpretation of the line AIP 92-12, shows the western boundary
of the Zorritos Piedra Redonda High and the Jurel and Perico leads. These
structures appear to have considerable potential as exploration targets. More
information can be found in Appendix 3 and Enclosure 3e............................... 44
Figure 19. Seismic interpretation of the line RIB 93-01. This section shows the
shallow and deep platforms, where the Merluza and Mero rollover structures
developed with high potential for exploration. More details can be found in
Appendix 3 and Enclosure 3g. ........................................................................... 45
Figure 20. Seismic interpretation of the line RIB 93-08, showing the potential of the
offshore tectonic structures in the shallow and deep marine platforms. The
Deeper Lobitos lead is defined to target the Paleozoic series in direct contact with
potential Cretaceous and Lower Tertiary source rocks. The Tiburon lead
corresponds to new structural leads in ultra deep waters. More details can be
found in Appendix 3 and Enclosure 3h.............................................................. 45
Figure 21. Seismic interpretation of the regional line RIB 93-16, showing the tectonic
elements of the Talara basin. On the left, the subduction trench is seen where the
oceanic crust pass under the continental crust. On the right, the shallow
platform shows the Calamar rollover structure and the Paleozoic lead. Potential
exploration targets in interpreted kitchen areas. More details can be found in
Appendix 3 and Enclosure 3i. ............................................................................ 45
Figure 22. Seismic interpretation of the line RIB 93-21, showing the Bayovar Bay
bounded by the Illescas and Paita Highs. The Bayovar Bay illustrates the many
structures associated to rollover anticline structures. According to seismic and
structural interpretations, these structures show high potential for exploration.
More details can be found in Appendix 3 and Enclosure 3j............................... 46
Figure 23. Seismic interpretation of the line PTP 99-23, located in an area where the
Talara to Sechura Basin merge. It shows the San Pedro and East San Pedro
structures. More details can be found in Appendix 3 and Enclosure 3k............ 46
Figure 24. Seismic interpretation of the line PTP 99-24, this section is located in an
area where the Talara merges with the Sechura Basin. It also shows the San
Pedro and East San Pedro structures. More details can be found in Appendix 3
and Enclosure 3l. ............................................................................................... 46
Figure 25. Seismic reference map. ............................................................................ 47
Figure 26. High Density Basement Map in NW Peru (Petrotech, 2001). .................. 49
Figure 27. Correlation between GCMS of a representative oil sample from the Talara
Basin and from an extract of a cutting sample of the Heath Formation in the
Piedra Redonda Field (Fildani, 2005)................................................................ 51
Figure 28. Gray shales of the Talara Shale offer good visual source rock character in
the Mancora area in two sites distanced some 20 Km. away.............................. 53
Figure 29. Total Organic Carbon in the Talara Basin, DGSI Data. ......................... 55
Figure 30. Total Organic Carbon in the Talara Basin, Previous Reports. ................ 55
Figure 31. Oil composition in the Talara and Tumbes Basins based on LC.............. 57
Figure 32. Total Organic Carbon in the Tumbes Basin, data from DGSI................. 63
Figure 33. Total Organic Carbon in the Tumbes Basin, data Perupetro Files.......... 64
4
Figure 34. Hydrocarbon occurrences in wells in the offshore Tumbes Basin........... 66
Figure 35. Temperature Gradient.............................................................................. 68
Figure 36. Basin Modeling in the Talara (La Casita 55X. Lomitos 3585 & 3835 wells)
and Tumbes Basins (Barracuda 154X, Corvina 40X & Pseudowell 1). ............. 70
Figure 37. Pre- Cretaceous and post-Cretaceous Maturity burials in the Lomitos
3585 Well. .......................................................................................................... 74
Figure 38. Post-Cretaceous Maturity burial in the Lomitos 3585 Well. .................... 74
Figure 39. Maturity Vs. Depth. 1D Modeling in the Negritos High in the Talara
Basin. ................................................................................................................. 75
Figure 40. Post-Cretaceous Maturity burial in the Lomitos 3835 Well. The Upper
Cretaceous in the Late Mature Window, the early Eocene interval in the midmature oil window and younger Formations in the early-mature oil window.... 77
Figure 41. Maturity versus Time plot in the Barracuda Lomitos 3835 Well.............. 77
Figure 42. Maturity versus Depth plot in the Lomitos 3835 Well. ............................ 78
Figure 43 and Figure 44. Burial history in Well SBX-A shows the base of the
Cretaceous Formation in the Mid Mature Window stage of the oil window and
the overlying section in the early mature window. ............................................. 80
Figure 45. Maturity Vs. Depth in Well La Casita 55X............................................... 81
Figure 46. Maturity Vs. Time in Well La Casita 55X. ............................................... 81
Figure 47. Burial history in Well SBX-A shows the base of the Muerto/Pananga
formations in the early stages of the oil window and the immature overlying
section. ............................................................................................................... 83
Figure 48. Maturity Vs Depth diagram in well SBX-A shows two major burial
histories.............................................................................................................. 83
Figure 49. Maturity burial in the Barracuda 15-4X Well shows the possible early
Eocene interval in the mid-mature oil window and the late Eocene and the
Mancora and Heath Formations in the early-mature oil window...................... 85
Figure 50. Maturity versus Time plot in the Barracuda 15-4X Well.......................... 85
Figure 51. Maturity burial in the Corvina 40X Well shows the bottom possible early
Eocene interval in the mid-mature oil window and the late Eocene and the
Mancora and Lower Heath Formations in the early-mature oil window........... 87
Figure 52. Maturity versus Time plot in the Corvina 40X Well................................. 87
Figure 53. Maturity burial in the Pseudowell 1 shows modeled stratigraphic units
from possible Eocene interval in the Main Gas Generation Window to immature
units from the upper Tumbes Formation to younger units. ............................... 89
Figure 54. Maturity versus Time plot in the Corvina 40X Well................................. 89
Figure 55: Prospects and Leads in Tumbes and North Talara Basin........................ 93
Figure 56: Two-way time structural map on the top Cardalitos Formation, showing
the Atun Prospect............................................................................................... 94
Figure 57: Seismic line OXY98-114 showing the east culmination of the Atun
structure. ............................................................................................................ 95
Figure 58: Seismic line OXY98-115a showing the west culmination of the Atun
structure. ............................................................................................................ 95
Figure 59: Two-way time structural map on the top Zorritos Formation, showing the
Banco Peru Prospective area. ............................................................................ 96
Figure 60: West to East seismic line Rib 93-01 across the Banco Peru Prospective
area .................................................................................................................... 97
Figure 61: Seismic line RIB 93-01 flattened on Zorritos Formation, showing the
Banco Peru structure and Tumbes basin ........................................................... 97
Figure 62: Seismic line RIB 93-02 across the Banco Peru structure ........................ 98
5
Figure 63: NW to SE seismic lines OXY 98-221 across the Banco Peru Structure. .. 98
Figure 64. Chita prospect defined by seismic line RIB 93-01, showing the principal
exploration targets. More details can be found in Appendix 3 and Enclosure 3p.
........................................................................................................................... 99
Chita Prospect...................................................................................................100
Figure 66: NW to SE seismic line PC 99-09 across the Chita Prospect....................100
Figure 67: Seismic line AIP 92-29 showing the Chita Prospect and the Barracuda
structure. ...........................................................................................................101
Figure 68: Structural 2WT on the top Zorritos Formation map, showing the Chita
stratigraphic prospect........................................................................................102
Figure 69: Composite seismic profile A-A1, showing the Chita stratigraphic lead...102
Figure 70: Isopach map of the Corvine Type lead on Zorritos Formation associated to
Chita Prospect...................................................................................................103
Figure 71: Deeper Delfín Lead defined by seismic line AIP 92-49, showing the
potential structural configuration and explorations targets. More detail can be
found in Appendix 3 and Enclosure 3p.............................................................104
Figure 72: Two-way time structural map on top Zorritos Formation showing the
Espada Lead......................................................................................................105
Figure 73: NW to SE seismic lines AIP92-66 showing the Espada Lead. ................105
Figure 74: Jurel Lead defined by seismic line AIP 92-12, showing the potential
structural configuration and explorations targets.............................................106
Figure 75 Lenguado Lead defined by seismic line AIP 92-49, showing the potential
structural configuration and explorations targets.............................................107
Figure 76. Merluza Lead defined by seismic line RIB 93-05, showing the potential
structural configuration and explorations targets. More detail can be found in
Appendix 3 and Enclosure 3p. ..........................................................................108
Paiche Prospect.................................................................................................109
Figure 78: NW to SE seismic lines OXY 98-210 showing the Paiche Structure.......110
Figure 79. Perico Lead defined by seismic line AIP 92-12, showing the potential
the Raya Prospect..............................................................................................112
Figure 81: Seismic line AIP 92-32 across the Raya Structure..................................113
Figure 82: North to South seismic line AIP 92-10 showing the Raya Structure ......113
the Toyo Prospect..............................................................................................114
Figure 84: SW to NE seismic line PC 99-16 across the Toyo Structure. ..................115
Figure 85: Seismic line AIP 92-41 showing the Toyo Prospect. ...............................115
Figure 86. Zorritos-Piedra Redonda Lead................................................................116
Figure 87. Calamar Lead defined by seismic line RIB 93-16, showing the potential
Appendix 3. .......................................................................................................118
Figure 88: Two-way time structural map on top of Paleozoic Basement, showing the
in the east the Tortuga prospect and in the west part, the Caballa structure.....119
Figure 89: West to East seismic line PTP 98-17, showing the Tortuga and Caballa
structure. See location on Figure 34.................................................................119
6
Figure 90. Deeper Lobitos Paleozoic Lead defined by seismic line RIB 93-08, showing
the potential structural configuration and explorations targets. More detail can
be found in Appendix 3 and Enclosure 3p. .......................................................120
Figure 91. Mero Lead defined by seismic line RIB 93-05, showing the potential
Figure 92: Tiburon Lead defined by seismic line RIB 93-08, showing the potential
TABLES
Table 1. Geochemical analyses in the Tumbes Basin. .............................................. 63
Table 2. Porosity and Permeability of Zorritos Formation in the Tumbes Basin. ..... 67
Table 3. Production tests in offshore wells in the Tumbes Basin............................... 67
Table 4. Heat Flow in the Talara.............................................................................. 71
Table 5. Well Sandino 6020 in the Talara Basin. ...................................................... 72
Table 6. Well Lomitos 3585 in the Talara Basin........................................................ 73
Table 7. Well Lomitos 3835 in the Talara Basin........................................................ 76
Table 8. Well La Casita 55X, Bayovar Bay. ............................................................... 79
Table 9. Well SBX-A Formations and Events............................................................ 82
Table 10. Well Barracuda 15-4X in the Tumbes Basin.............................................. 84
Table 11. Well Corvina 40X in the Tumbes Basin. .................................................... 86
Table 12. Pseudowell 1 in the Tumbes Basin............................................................. 88
Table 13: List of Prospect and Leads in Tumbes Basin and South Talara Basins .... 92
ENCLOSURES
Enclosure 1a. Tumbes – Talara Basins Base Map, North.
Enclosure 1b. Tumbes – Talara Basins Base Map, South
Enclosure 1c. Talara Basin Base Map, South
Enclosure 1d. Tumbes – Talara Basins Geological Map
Enclosure 2a. N-S Structural-Stratigraphic Cross Section
Enclosure 2a-1 and 2. N-S Flattened Stratigraphic Cross Sections
Enclosure 2b. E-W Structural-Stratigraphic Cross Section
Enclosure 2b-1, 2, 3 and 4. E-W Flattened Stratigraphic Cross Sections
Enclosure 2c. NW-SE Structural-Stratigraphic Cross Section
Enclosure 2c-1. Flattened NW-SE Stratigraphic Cross Section
Enclosure 2d. NW-SE Structural-Stratigraphic Cross Section
Enclosure 2d-1 and 2. NW-SE Flattened Stratigraphic Cross Sections
Enclosure 2e. NE-SW Structural-Stratigraphic Cross Section and
Enclosure 2e-1 Flattened NE-SW Stratigraphic Cross Section
Enclosure 2f. NE-SW Structural-Stratigraphic Cross Section
Enclosure 2f-1 and 2. NE-SW Cross Sections
Enclosure 2g. NE-SW Structural-Stratigraphic Cross Section
Enclosure 2g-1, 2 and 3. NE-SW Flattened Stratigraphic Cross Sections
Enclosure 2h. NW-SE Structural-Stratigraphic Cross Section
Enclosure 2i. WSW-ESE Structural-Stratigraphic Cross Section
Enclosure 2i-1, 2 and 3. WSW-ESE Flattened Stratigraphic Cross Sections
7
Enclosure 2j. NW-SE Structural Cross Section S1-S1’
Enclosure 2k. NW-SE Structural Cross Section S2-S2’
Enclosure 2l. NW-SE Structural Cross Section S3-S3’
Enclosure 2m. NW-SE Structural Cross Section S4-S4’
Enclosure 2n. N-S Structural Cross Section S5-S5’
Enclosure 2o. W-E Stratigraphic Cross Section S6-S6’
Enclosure 2p. W-E Structural Cross Section S7-S7’
Enclosure 2q. W-E Structural Cross Section S8-S8’
Enclosure 2r. SW-NE Structural Cross Section S9-S9’
Enclosure 2s. W-E Structural Cross Section S10-S10’
Enclosure 2t. SW-NE Regional Cross Section R1-R1’
Enclosure 3a. Seismic interpretation line PC 99-01
Enclosure 3b. Seismic interpretation line AIP 92-49
Enclosure 3c. Seismic interpretation line RIB 93-01
Enclosure 3d. Seismic interpretation line RIB 93-30
Enclosure 3e. Seismic interpretation line AIP 92-12
Enclosure 3f. Seismic interpretation line AIP 92-60
Enclosure 3g. Seismic interpretation line RIB 93-05
Enclosure 3h. Seismic interpretation line RIB 93-08
Enclosure 3i. Seismic interpretation line RIB 93-16
Enclosure 3j. Seismic interpretation line RIB 93-21
Enclosure 3k. Seismic interpretation line PTP 99-23
Enclosure 3l. Seismic interpretation line PTP 99-24
Enclosure 3m. Regional cross section A-A’
Enclosure 3o. Regional cross section B-B’
Enclosure 3p. Regional cross section C-C’
Enclosure 3q. Leads and Structures Map of The Tumbes and North of Talara Basins
Enclosure 4a. Top Middle Eocene (North) Tumbes Basin, TWT Structure Map
Enclosure 4b. Top Middle Eocene (South) Tumbes Basin, TWT Structure Map
Enclosure 4c. Top Middle Eocene (North - South) Tumbes Basin, TWT Structure Map
Enclosure 4d. Top Muerto Fm.(Talara Basin), TWT Structure Map
Enclosure 4e. Top Zorritos Fm., TWT Structure Map Tumbes Basin
Enclosure 4f. Top Cardalitos Fm., TWT Structure Map Tumbes Basin
Enclosure 4g. Cardalitos Fm., TWT Isochrone Map.
Enclosure 4h. Top Middle Eocene (North), Prospects and Leads TWT Map
Enclosure 4i. Top Middle Eocene (South), Prospects and Leads TWT Map.
Enclosure 5a. Digital Elevation Model (DEM to 90m) Peruvian Basins.
Enclosure 5b. Morphological/Structural Configuration in the Andean Cordillera.
Enclosure 5c. Tumbes and Talara Forearc Basin Geometry and Structural Style, I
Enclosure 5d. Tumbes and Talara Forearc Basin Geometry and Structural Style, II
Enclosure 5e. Tumbes and Talara Forearc Basin Geometry and Structural Style, III
Enclosure 6. 1 CD containing Digital Data:
a.
Report: Text and figures in A4 & A3 format
b.
Enclosures 1 through 6 in various formats
c.
Appendices 1 through 5
8
APPENDICES
1. Compilation: Geochemical Database for the Talara and Tumbes Basins and
adjacent Lancones and Sechura Basins.
2. Report: “Reconocimiento Geológico. Área Máncora: Quebrada Seca,
Fernández-Máncora, Cabo Blanco”, Ysabel calderón, May 2005.
3. Report: “Análisis de la Geometría y Estilo de Deformación de las Cuencas
Talara y Tumbes: Nuevos Leads de Exploración”, Wilber Hermoza, December
2005.
4. Summary of Previously Defined Prospects and Leads in the Tumbes Basin, after
“Occidental Petrolera del Perú, Inc., Sucursal del Perú, Departamento de
Exploración, Cuenca Progreso – Tumbes, Perú, Block Z-3, Reporte Final,
Diciembre 2001“.
5. Spread sheet of Wells Logs with LAS format in the Talara and Tumbes Basins.
9
EXECUTIVE SUMMARY
The Talara and Tumbes Basins has been the site of extensive hydrocarbon exploration
and exploitation since the XIX century. The first well in Peru was spudded in Zorritos
in 1863 and by year 1920 nearly 1000 wells had been drilled in the basins. To date,
eighteen wells have been drilled in the offshore Tumbes Basin and some 13,200 wells in
the Talara Basin, including near 1,300 offshore wells.
Cumulative production is about 1.4 BBO and 1.7 TCF, mainly from the Talara Basin.
Published literature establishes a mean estimated recoverable undiscovered
hydrocarbons in the Talara Basin in the range between 2.2 to 1.71 BBO, 5.84 to 4.79
TCFG, and 255 MMB of NGL, of which between 85% to 70% are offshore and
between 15% to 30% onshore. Mean estimated recoverable undiscovered oil, gas and
natural gas liquids in the Tumbes (Peru) and bordering Progreso Basin (Ecuador) is to
237 MMBO, 255 BCFG, and 32 MMB of NGL. Over 90% of the oil produced come
from areas did not count with seismic data.
There is a high hydrocarbon potential in the unexplored shallow and deep water for
Eocene as well as for the pre-Eocene objectives in the Talara Basin and in the numerous
undrilled prospects and leads to target the Oligocene and Miocene objectives in the
largely unexplored Tumbes Basin. All hydrocarbon exploration and development in
both basins have been performed on the onshore and in the offshore portions of the
basins in water depths of less than 120m. The 2005 year San Pedro oil discovery in
Paleozoic metamorphic rocks in the Bayovar Bay testifies the exploration potential for
the undiscovered reserves.
The Tumbes and Talara Basins have excellent potential with a variety of opportunities
that remain as untested prospects and leads to target extensive stratigraphic columns. In
the course of this geophysical and geological evaluation six of them in the Talara Basin
and thirteen in the Tumbes Basin have been documented in Chapter 8, in the Regional
Tectonic Settings in Chapter 5.3 and in Appendix 3. The areas adjacent to some of them
also offer additional exploration opportunities of the pre-Eocene section as the border of
the shallow and deep platforms in the Talara Basin.
The attractiveness for hydrocarbon exploration of potential Cenozoic and Paleozoic
sections in the Banco Peru had never been recognized. This feature has poor seismic
definition and it is larger than the Talara Negritos High, which has a cumulative
production of over 600 MMBO, most of which was produced in areas with no seismic
data. Additionally, oil discovery in the San Pedro 1X well renewed hydrocarbon
exploration of the Paleozoic rocks in the whole NW Peruvian basins.
Although most areas in these basins are under different exploration stages, there exist
prospects and leads of especial interest for future promotion as those defined in open
areas or in areas under PEA’s (Block Z-34) or under negotiations (Blocks Z-37 and Z38) where license contracts will be signed. Previous studies defined other potential
prospects and leads, but with a different untested petroleum system as defined in the
present study (Appendix 4).
The Talara and Tumbes Basins are two fore-arc basins genetically related to plate
tectonics, the action of the South American and the Nazca plates overriding the
10
subduction oceanic crust. Presence of good siliciclastic reservoirs, excellent quality
source rocks, trapping mechanism and abnormal high temperature gradient created
particular conditions to form a unique giant oil basin.
The Talara and Tumbes Basins include thick sedimentary stratigraphic sequences of
sediments of Paleozoic to Tertiary age that extend offshore and onshore along the
Coastal region. Both basins constitute two fore-arc basins each with very thick
sedimentary sections of Paleogene and Neogene ages. Sediment source to the east
deposited up to 9,700 m. of sediments of Paleocene, Eocene and early Oligocene ages
overlying the Cretaceous in 35 my in the Talara Basin. Thickness of the late Oligocene
to Pliocene age in the Tumbes Basin reaches 7100 m., all the sections deposited in
approximately 30 my.
A major petroleum system accounts for most hydrocarbons in the Talara Basin.
Oleanane biomarkers in oils and extracts define source rocks of late Cretaceous to
Tertiary age. Formations of Eocene age constitute the main siliciclastic reservoirs with
shale seals. Basin modeling interprets the presence of hydrocarbon kitchens originally
connected to the area now occupied by the Negritos - Talara High and supposedly
similar kitchens must have been connected to the Lobitos and El Alto - Peña Negra
Structural Highs. Hydrocarbon generation and migration occurred from possibly
offshore kitchens to the west, where source rocks should have better organic contents,
since late Eocene to Oligocene time prior to the major complex block faulting with
sealing faults characterizing these highs. The extension of the petroleum system to the
deep offshore portion of the basins is unknown. Other potential kitchens have been
previously defined in the oil and gas windows in the adjacent deep Lagunitos, Malacas
and Siches grabens bordering the three major structural highs.
A more complex petroleum system, or more than one, is interpreted to be present in the
Tumbes Basin to account for the oil produced, the various oil and gas tests and the
numerous hydrocarbon shows detected in the Oligocene and Miocene stratigraphic
sequences. Source rocks and siliciclastic reservoirs of these ages are documented in the
whole section possible superimposed on older petroleum systems. The geochemical
analyses, hydrocarbon occurrences and basin modeling indicates the presence of active
kitchens in deeper portions of the basin where the various source rocks acquired
maturity enough to generate and expulse hydrocarbons.
The assemblage of 9,814.55 km. of offshore 2D seismic lines in SEG-Y format and a
well database in LAS format of 785 onshore and offshore wildcat and development
wells constitute notable accomplishment of this study. 37 synthetic seismograms were
created for wells in the Talara and Tumbes Basins. An Excel geochemical database
compiled with newly acquired data and all available data of the coastal basins in the
Perupetro files is also included in the report as Appendix 1.
11
1.0. INTRODUCTION
The Talara and Tumbes Basins are located on the NW coast of Peru (Figure 1). Drilling
in these basins started a few years after Colonel Drake drilled its first well in Titusville,
USA in the XIX century. Before oil production from the Marañon Basin reached the
coast in the mid 70’s, all hydrocarbon production was from the Talara Basin.
Primary interest to initiate this study is the acknowledgment of the potentiality of the
undiscovered hydrocarbons reserves in Talara and Tumbes Basins. As an example of
what can be accomplished with very active shallow drilling was provided by the
primary production obtained by the intense infill drilling between 1978 and 1982 with
Helico and Echino Formations as objectives and secondary recovery afterwards in what
is basically the present Block X in the Talara Basin (Organos, Patria, Somatito, Central,
Carrizo, Cruz and Folche fields). Under a contract with Petroperu S.A., OXY drilled
almost 1,000 wells, which represented completion of one well per day. The oil
production for the block increased from 6,500 to 21,000 BOPD.
Additionally, both the Talara and Tumbes Basins offshore have not been drilled in
water depths deeper than 120 m. There is a high potential in the unexplored deep water
in the Talara Basin for Eocene as well as for the pre-Eocene objectives and in the
numerous undrilled prospects and leads in the largely unexplored Tumbes Basin..
According to the USGS (Higley, 2001), Mean estimated recoverable undiscovered oil,
gas and natural gas liquids in the Talara Basin amounts to 1.71 BBO, 4.79 TCFG, and
255 MMB of NGL. These values represent the mean confidence level, mainly from
Eocene-age sandstones and turbidites. Eighty-five percent of the undiscovered resources
are in the offshore portion of the basin. “Oil production is dominant, but excellent
potential is indicated for offshore gas discoveries. Gas resources are mostly untapped
because of the limited markets and gas infrastructure”. Cumulative Production in the
basin to 2003 is 1.416 BBO and 1.7 TCFG. Offshore operator Petrotech numbers are
even higher placing the proven undeveloped and undiscoverable recoverable reserves in
2.2 BBO and 5.84 TCFG, of which 70% is offshore and 30% onshore (Gonzales and
Alarcon, 2002).
Mean estimated recoverable undiscovered oil, gas and natural gas liquids in the Tumbes
(Peru) and Progreso (Ecuador) basins amounts to 237 MMBO, 255 BCFG, and 32
MMB of NGL. These are also figures from the USGS (Higley, 2001).
The Peruvian Ministry of Energy and Mines groups hydrocarbon statistics for the
coastal onshore and offshore producing basins, basically the Talara and Tumbes Basins.
MEM total undeveloped, probable and possible reserves amount to 1.35 BBO and 5.3
TCF. Cumulative production for year 2003 in Perupetro S.A. files is set to 1.4 BBO and
1.7 TCF, mainly from the Talara Basin.
The emphasis on the current work has been on well and seismic data gathering, quality
controlling and correcting the data and in presenting the stratigraphic and structural
framework of the basin. The present report is as complete an evaluation of the Talara
and Tumbes Basins as the data permitted to accomplish. This study represents an
excellent starting point to be continued with a more detailed examination of the basin.
Despite receiving additional data sets needed for the interpretation within the last two
12
months of the study to complete the analysis, most of the objectives have been met. The
new data was loaded into the database and quality control of it will be needed in the
future.
Figure 1. Location Map. NW Coastal Basins with location of the Talara and Tumbes Basins.
13
The SEGY seismic and LAS well data utilized in this project was supplied originally by
Perupetro and by the operators of the various licenced blocks involved. The Basin
Evaluations Funtional Group of Perupetro S.A. performed the current report.. The 2D
seismic was interpreted primarily utilizing Schlumberger Geoframe UNIX based
seismic interpretation software. On the geological side, Geographix and DigiRule
software were used extensively for mapping, well log editing and cross-section
construction.
1.1. Regional Basin Description
Peru is divided into four main morphological regions, three onshore and one offshore.
The three onshore regions include the Andes Cordillera Region in the center, the SubAndean Region to the east of the Andean Cordillera and the Coastal Region to the west
bordering the Pacific Ocean. The Offshore Region encompasses the Pacific Ocean.
Nineteen sedimentary basins extend in all these regions with current hydrocarbon
production in all including the Andes Region.
The Coastal Region is a narrow land strip separating the Andes from the Pacific Ocean.
This region incorporates 11 sedimentary basins some of which extend to the Offshore
Region as one single basin and others are separated by inferred regional faults parallel
to the shoreline. This report will concentrate on the northwestern Coastal Region and
NW Offshore Region, which has been the site of extensive hydrocarbon activities for
over 130 years in the known Talara and Tumbes Basins.
The Talara Basin trends NE-SW parallel and to the W and NW of the Amotape
Mountains (Figure 1). The basin is limited to the south at the Paita High by the western
extension of the continental E-W trending Huancabamba deflection fault system at its
Pacific Ocean termination. The Huancabamba Deflection is a mega-shear running
approximately all its way to the east along the Amazon River to the Atlantic Ocean. At
its southern border and to the southeast in the Bayovar Bay, the site of the 2005 San
Pedro oil discovery, the Talara Basin is partially connected with the Sechura Basin.
Further to the north, the basin is bordered by the Amotape Mountains to the east and
northeast; these mountains separate the Talara Basin from the Lancones Basin. The
Talara Basin merges north into the Tumbes Basin in the Punta Sal Beach area, located
some 15 Km. north of the Mancora City.
The onshore Talara Basin extends offshore with a topographic character defined below
in the Bathymetry section of this report. The bathymetry defines a shallow and a deep
platform caused by the listric Talara Fault, a regional mostly NS fault that creates the
major rollover anticlinal lead with Cenozoic, Mesozoic and possibly Paleozoic
sediments (Enclosure 3p). The Talara Fault extends north to the south end of the Banco
Peru Fault.
The bulk of drilling and production is focused in the three major structural highs Peña
Negra, Lobitos and Talara/Negritos in the Talara Basin. Some 14,000 wells established
a cumulative production and the additional proved, probable and possible reserves
mentioned above, mostly from Tertiary lower Eocene reservoirs.
14
The Tumbes Basin is a tectonic depression with a similar NE-SW trend as the Talara
Basin. The basin continues north into Ecuador as the Progreso Basin. The east and NE
onshore border approximately coincides with the Zorritos-Piedra Redonda High
(Enclosure 3p). This high is limited to the west by a fault system formed by the Piedra
Redonda and Tumbes Faults and to the east by a listric fault system that includes the
Carpitas and Tronco Mocho faults. The NW border of the Tumbes Basin includes the
Banco Peru Structure. This feature is described as a sea mound or tectonic high with a
remarkable topographic expression with shallowest expression of some 50 km2 in water
depths less than 100 m. and whose composition and origin remains to be established.
The Banco Peru Structure is larger than the Talara Negritos High, the largest tectonic
high in the Talara Basin. A chaotic sedimentary section of possible Cenozoic and
Paleozoic age is present in deep waters west of the Banco Peru Structure (Enclosure 3c).
1.2. Bathymetry
The sea bottom was mapped from topographic data acquired from the seismic
campaigns (Enclosures 1a, 1b, 1c and 1d). In the Tumbes Basin at the Peru/Ecuador
border the 500 m. isobaths extends 100 km. from the coastline west past the western
slope of the Banco Peru (Enclosure 1a). Some 50 km2 of the shallow Banco Peru lies
above the 100 m. isobaths. The deepest portion of the Tumbes Basin is located to the SE
and S of the Banco Peru in water depths that increase from 500 to over 1000m. West of
Punta Sal at the southern border of the basin the 500, 1000 m. and 2000 m. isobaths
extend 20, 30 and 50 km. from the coastline. All wells in the offshore Tumbes Basin
were drilled in water depths shallower than 120 m.
Most of the offshore Talara Basin shows two major platforms (Enclosures 1b and 1d).
The first platform with water depths shallower than 200 m. extends 8 to 12 km. from the
coastline in front of the three main structural highs El Alto/Peña Negra, Lobitos and
Talara/Negritos. All wells drilled in the offshore Talara Basin are located on this
platform. The second platform is 40 km long by 15 km. wide in water depths in the
range between 2200 m. and 3000 m. The eastern border of this platform is located some
20 km. west of the El Alto/Lobitos/Talara coastline. An elongated N-S slope separates
the two platforms where the sea bottom drops rapidly from 200 to 2200 m.
In the southern Talara Basin, the sea bottom widens conspicuously in front of the
Lagunitos, Paita High, Chira Bay and Bayovar Bay (Enclosure 1c). On these bays the
500 m. isobaths extends 20, 30 and 35 km offshore. from the coastline and drops more
rapidly beyond this water depth. The same 500 m. isobaths is narrow in front of the
offshore extension of the onshore Paita and Illescas Highs.
15
2.0. PREVIOUS WORK IN THE STUDY AREA
The onshore Talara and Tumbes Basins has been the site of extensive hydrocarbon
exploration and exploitation since the XIX century by several companies. Fabrica de
Gas de Lima spudded the first well in Peru in Zorritos in the Tumbes Basin on
November 2, 1863. The first cable well was drilled in Negritos in the Talara Basin in
1874 and by year 1920 nearly 1000 wells had been drilled (Travis, 1953).
2.1. Talara Basin
Drilling in the Talara Basin started in the late XIX century. In the late half of the XX
century active oil companies were Compañia Petrolera Lobitos, the state oil company
Empresa Petrolera Fiscal and Exxon’s International Petroleum Company until 1970.
IPC acquired the “Concesiones Lima” from the Compañia Petrolera Lobitos in the
1950’s. The state oil company Petroleos del Peru S.A., Petroperu S.A. took over all
onshore upstream and downstream operations in NW Peru in the late 60’s. Petroperu
abandoned the upstream hydrocarbon business in the 90´s. OXY also operated several
onshore oil fields between 1978 and 1996 as a secondary recovery project.
Production in NW Peru comes mainly from the offshore and onshore Talara basin fields
and minor production from small onshore Tumbes Basin fields. Old onshore fields were
compartmentalized as smaller production units from the 80´s and are currently operated
by several oil companies. These companies include the following (Enclosures 1a, 1b, 1c
and 1d):
1.
2.
3.
4.
5.
6.
7.
8.
9.
Petrobras Energia Peru S.A. in Block X,
Sapet Development Peru Inc., Sucursal Del Peru in Blocks VI and VII,
Graña y Montero Petrolera S.A. in Blocks I, and V,
Petrolera Monterrico S.A. in Blocks II, XV and XX,
Empresa Petrolera Unipetro ABC S.A.C. in Block IX,
Cia. Petrolera Rio Bravo S.A. in Block IV,
Mercantile Peru Oil & Gas in Block III,
Petrotech Peruana S.A. in offshore Block Z-2B
Graña y Montero Petrolera in Block XIV, onshore Tumbes Basin,
The offshore extension of the Talara Basin has been in exploration and production since
the 1970´s as the first offshore operation in South America. Belco Petroleum
Corporation originally operated the Talara Basin offshore; Petromar S.A. followed it
from the late 1980’s and by Petrotech Peruana S.A from the mid 1990’s. Total 2D
seismic amounts to 12,004 Km. and 1584 Km. of 3D seismic. Petrotech currently has
the only offshore hydrocarbon producing operation in Peru in Block Z-2B and holds an
exploration license with no production in Block Z-6 in the south Talara Basin.
2.2. Tumbes Basin
The state oil company Empresa Petrolera Fiscal (Empresa Petrolera Fiscal) carried out
extensive field geology work and exploratory and development drilling in the border
with the Talara Basin until the late 1960’s. In the early 1960’s there was gravity and
aeromagnetic data acquisition by Empresa Petrolera Fiscal in the Los Organos area in
the Talara and Tumbes Basins. Graña y Montero Petrolera S.A. also acquired 2D
16
seismic and conducted wildcat and development drilling since the early 1990’s in old
Block V in this area.
The offshore Tumbes Basin has been covered by several 2D seismic campaigns. In the
early 1970’s Petroperú and the Joint Venture Petroperú & Tenneco-Unión- Champlin
acquired 2300 and 1612 Km of 2D seismic. The Joint Venture drilled 9 wells in 4
structures. Belco Petroleum Corporation joined the group, acquired 600 Km of 2D
seismic in 1976 and drilled 10 wells (one was a deepening). Belco established oil
production in the Albacora field in the early 1980’s. Of the eighteen wells drilled in this
period, gas was discovered in the Piedra Redonda and Corvina structures and oil in the
Albacora field near the Ecuadorian border. A small oil production was established in the
Albacora field and was later abandoned by Belco. All drilling was carried out in
maximum water depths of 120m. Gas was also discovered north of Albacora in the
Amistad field across the border in Ecuador.
Interest in the offshore Tumbes Basin was resumed in the 1990’s. American
International Petroleum Company acquired 1850 Km of 2d seismic in 1991. Occidental
Petrolera del Peru Inc., Sucursal Del Peru acquired 1759 km of 2D Seismic in 1998 in
modern Block Z-3 . OXY made a Geological/Geophysical evaluation of the ex-Block Z3 in 1998 based on new and reprocessed 2D seismic all tied to existing well data in
Block Z-1. The 1759 Km. of new 2D seismic covers the westernmost extension of the
Tumbes Basin including the Banco Peru; the seismic was spaced 2 Km apart for both
the dip lines and the perpendicular tie lines. Additionally, OXY reprocessed 387.55 and
680.1 Km. of seismic acquired by Belco Petroleum Corp. in 1982 km and by AIP
between 1992-93, respectively. Good correlation of seismic events tied to stratigraphic
units was established in the most of the Z-3 block. Time to Depth conversion was not
attempted and was recommended to perform with the future 3D seismic. OXY’s
evaluation defined a series of Prospects and Leads, which with additional data gathered
in the present study are included in Appendix 4. Perez Companc S.A. acquired 1014
Km and reprocessed 1044 km of 2d seismic in modern Block Z-1 in 1999. BPZ holds
current exploration licensees in onshore Block XIX and offshore Block Z-1.
Most of the remaining areas in the Talara and Tumbes Basins are under either
exploration licensees, negotiations for license contracts, TEA’s or PEA’s. BPZ Energy
Inc., Sucursal Peru has currently Block Z-1 under an exploration license in the offshore
Tumbes Basin. Present operations in Block Z-1 is to develop existing certified proven
gas reserves in the old Corvina and Piedra Redonda gas discoveries to build an
electrical plant to generate 160 MW and to export gas to Ecuador. BPZ also holds Area
XIV in the Tumbes Basin under a TEA, Gold Oil PLC holds a PEA in Area Z-34 in the
offshore Talara Basin. Blocks Z-38 in the main body of the Tumbes Basin and Block
Z-37 in front of and to the south of the Bayovar Bay are under negotiations for
exploration license contracts.
The Sechura and Lancones basins adjacent to the present study have been the subject of
exploration and/or TEA’s requests in the past 10 years. Most notably are the
commercial operations developing dry gas by Olympic Peru Inc., Sucursal del Peru, in
Block XIII in the Sechura Basin. Petrotech’s oil discovery in the Bayovar bay has
renewed interest to target the Paleozoic metamorphic rocks in the area and its landward
continuation in the Sechura Basin.
17
3.0. DATA GATHERING
3.1. Database
A digital database was prepared using available data from various seismic campaigns
and wells. A wide range of appropriate seismic coverage of the Talara and Tumbes
Basins was thus obtained with all these campaigns. Seismic used in this evaluation
includes 9,814.550 Km of digital data in SEG-Y format from the following eight 2D
seismic campaigns:
1.
2.
3.
4.
5.
6.
7.
8.
AIPGCP92LZ1 (American International Petroleum Corp.)
RIBDGC93LZ1 (Ribiana)
OXYWG98LZ3 (Occidental Sucursal del Perú).
PETPMS98LZ2B (Petro-Tech Peruana)
PCOWG99LZI (Perez Companc)
PETPET99LZ2B (Petro-Tech Peruana)
Digital wire-line well logs in LAS format were very limited in the Perupetro files.
Numerous wells were not available in digital format for the present evaluation. The
Perupetro S.A. Geological and Geophysical Evaluation Group (GFEGG) obtained
additional data throughout several requests to the local companies and loaded a total of
785 onshore and offshore wildcat and development wells in its database. In fact, some
companies still lack digitized wire-line logs and work only with hard copies and others
have 5-6 digitized logs in blocks with several hundred wells. Additionally, only some
50% of the obtained digitized wire-line logs were QC’d in time to incorporate them to
the project. Some wells lacked several curves completely and others were partially
digitized, so that mainly the GFEC completed digitizing them with some Schlumberger
support. Perupetro S.A. obtained very good support from the operating companies in
both basins.
The geological map presented in the northern base maps is a compilation of BPZ data,
currently active in the NW Coastal Region (Enclosures 1a and 1b). Some discrepancies
are present on the topographic compilations of the seismic and surface geology with
mismatch of different sets of data increasing from north to south. We can attribute these
discrepancies to the coordinate systems used and possibly to the scanning procedure of
the geological map.
18
4.0. SCOPE OF PROJECT
This project was intended to be a regional geological and geophysical evaluation of the
Talara and Tumbes Basins focusing on the identification of new deep pre-Eocene play
types supported by seismic data. The focus was to examine the basins through the
interpretation of digital seismic and well data sets, with each being tied to one another,
using previously completed well datasets. However, reliable well data availability
restricted our analysis to newly acquired and newly quality controlled datasets by the
group in the offshore region, tied in as many places as possible with onshore well data.
A more complete tie was obtained in the Tumbes Basin with seismic data of good
quality and all wells completed in LAS format.
Based on our past experience with the PARSEP Projects, the more time consuming
aspects of this evaluation was the standardization and quality control of the data. Digital
curve data was compiled and edited for the available digital wells especially wildcats in
the Basin (Enclosures 1a, 1b and 1c). A composite log for each well was constructed,
which if available included a Caliper, SP, Gamma Ray, Deep and Shallow Resistivity,
Density, Neutron and Sonic curves. These composite logs are available as a LAS file as
part of this report.
A series of 20 stratigraphic and structural cross-sections shown in Figure 4 were
constructed across the basins to standardize and reveal the stratigraphic relationships in
the southern and northern Talara Basin and the Tumbes Basin (Enclosures 2a through
2t). Several flattened X-sections were prepared from these stratigraphic-structural cross
sections in the Talara Basin and presented as part of these Enclosures. A standardized
well database in Access was developed with standardized well tops, well data and other
information when available, but it has not been completed on this stage of the project.
Regional and detailed geological and geophysical analyses that defined prospects and
leads in the Talara and Tumbes Basins were prepared as part of the report. The Regional
Tectonic settings in chapter 5.3 of this report is a summary of a more complete and
detailed analysis of the tectonics presented in Spanish as Appendix 3. This regional
context is a geometric and structural analysis of the two fore-arc basins based on the
interpretation of 13 offshore seismic lines, three of which are tied to onshore seismic,
well and surface geological data in the area north of the Mancora city (Enclosures 3a
through 3p). The detailed seismic interpretation mapped five seismic horizons
(Enclosures 4a through 4g) to define the Prospects and Leads Chapter 8.0 in
conjunction with the prospects and leads also defined by the regional tectonics
mentioned above. A total of 13 and 6 Prospects and Leads are documented with either
the appropriate regional geological interpretations of seismic lines and/or seismic
structural maps in the Tumbes and Talara Basins, respectively (Figures 55 to 92).
In the Petroleum Geology in Chapter 7.0 the report includes a general discussion of
available Geochemical data sets used also for burial modeling and attempting to define
the petroleum systems. Hydrocarbon occurrences, maturity and analyses of potential
source rocks in the different Cretaceous, Paleogene and Neogene formations are
described. Reservoir, seals and traps and potential kitchen areas are also discussed.
Thermal maturity and hydrocarbon generation modeling were conducted on four wells
in the Talara Basin and two wells and a Pseudowell in the offshore Tumbes Basin
19
(Figure 36). Appendix 1 includes a Geochemical database for the Talara and Tumbes
Basins and the adjacent Lancones and Sechura Basins.
The assemblage of these entire seismic, well, Geochemical data sets is one of the more
notable accomplishments of this study. The geophysical analysis counted with good
quality modern seismic. The eight surveys of 2D SEG-Y Digital Seismic Data represent
coverage throughout most of the Basins (Figure 25 and Enclosures 1a, 1b and 1c).
Additionally, the group edited 37 synthetic seismograms for wells in Talara and Tumbes
Basins (1 onshore only). The 3D seismic analysis was not performed on the present
evaluation.
20
5.0. GEOLOGY OF THE TALARA AND TUMBES BASINS
5.1. Regional Geology
The Talara and Tumbes Basins include thick sedimentary stratigraphic sequences of
sediments of Paleozoic to Tertiary ages that extend offshore and onshore along the
Coastal region far beyond the present basins. They merge and are part of the regional
sedimentary succession characterizing all the Peruvian territory that eventually pinch
out onto the Brazilian and Guyana Shields. The complex geological evolution of all
these sequences is controlled by two regional tectonic systems recognized in the basins
of Peru. The first, the pre-Andean System, encompasses three cycles of Ordovician,
Devonian and Permo-Carboniferous ages overlying the Precambrian basement of the
Guyana and Brazilian Shields. The second, the Andean System, was initiated with the
beginning of subduction along the western margin of Peru. It encompasses several
mega-stratigraphic sequences and numerous minor sedimentary cycles, ranging from
Late Permian to the Present.
The stratigraphic columns that have been used in the present report are representative of
all NW Peru and are presented in Figure 2 and Figure 3. They show distinctive imprint
of the tectonics and/or sedimentation history that dominated the NW coastal area greatly
influenced by various pulses dominating the plate tectonics in this region.
The base map presented as Enclosure 1d includes a surface geological map of the Talara
and Tumbes Basins, north of the Chira River. This map has been provided by BPZ a
current exploration company with licensees in the onshore north Talara Basin, onshore
and offshore Tumbes Basin and negotiating a license contract for the whole Lancones
Basin.
5.1.1. Pre-Andean System
The pre-Andean tectonic cycle includes Ordovician, Silurian, Devonian and the PermoCarboniferous cycles all overlying crystalline/metamorphic Basement. This tectonic
system preserved discontinuous successions of Ambo/Cabanillas/Contaya and a more
continuous Tarma/Copacabana/ and Ene/Red Bed Groups, which reveal complex
tectonics. This tectonism includes a possible pre-Cabanillas rifting and peneplanation
and a late Permian uplift and erosional episode (PARSEP, 2002). Of all these
successions only a portion of the Paleozoic represented by the Tarma Group consisting
of 1,500 m. of quartzite, quartzitic sandstones, argillites and slate is preserved in NW
Peru, possibly overlying a crystalline Basement.
The Permo-Carboniferous cycle overlies unconformable the Devonian and/or
Ordovician Cycles and Basement in the uplifted areas. This cycle has a widespread
distribution throughout most of the Peruvian basins and neighboring basins bordering
the Guyana and Brazilian shields. In the Peruvian basins, the earliest Carboniferous
sedimentation is represented by the Ambo Group, which was deposited as continental to
shallow marine, fine-grained sandstones, interbedded siltstones, gray shales, and
occasional thin coal beds. These sediments are followed vertically by the thin
transgressive, clastic-rich Tarma Formation, which is usually conformably overlain by
the normally thick, massive dark gray, fossiliferous, shelf carbonates of the Copacabana
Formation. The thick sequence of Copacabana limestones (wackestones, packstones and
21
grainstones), and thin interbeds of dark gray shales and anhydrites are not recognized in
the Talara and Tumbes Basins.
Figure 2. Stratigraphic Column of the Talara Basin. Figure modified from old IPC files.
22
Figure 3. Stratigraphic Column of the Tumbes Basin. Figure modified from OXY (2000).
23
5.1.2. Andean System
“The Andean System was initiated simultaneously with the beginning of subduction
along the Pacific margin. A major change in the tectonic regime along the northwestern
border of the South-American plate promoted isostatic rearrangements. In a global
scale, the initial phase of the Andean System developed during the Pangea break up …
The development of the Andean subduction zone during late Permian to early Triassic
times is supported by geological information gathered … along the Peruvian Eastern
Range, where they recognized a Permo-Triassic continental volcanic arc.” (PARSEP,
2002).
The Late Permian, Triassic to Jurassic tectono-stratigraphic sequence (equivalent
Mitu/Ene, Pucara and Sarayaquillo of the sub-Andean basins) is absent due to nondeposition and/or erosion in the Talara and Tumbes Basins. Tectonic accommodation
processes followed the late pre-Andean Tectonics coinciding and merging with a long
time episode related to the regional Nevadan unconformity over which lies sediments of
Cretaceous age, a generally well recognized regional first order sequence boundary. The
Talara fore-arc Basin originated first as an individual basin during late Cretaceous and
extended in time throughout Eocene time followed by the Tumbes Basin whose origin
as a fore-arc Basin began in early Oligocene time. Inversion processes uplifted the
western Marginal High (Amotape Mountains, Paita High, etc.) that restricted early
Cretaceous deposition to the west of the Coastal Region.
Oldest Cretaceous deposition in the Talara Basin records rocks of Aptian age and was
characterized by a westerly wedge of marine to fluvial and marginal clastics. The
Cretaceous deposition was again interrupted by non-deposition/erosion between
Cenomanian and Santonian. Deposition resumed continuously during late Cretaceous
Campanian and Maastrichtian, Paleocene, Eocene and early Oligocene, a long time
episode represented by a continuous stratigraphic succession. This succession includes
short time breaks marking the arrival of the first pulses of the Andean Orogeny
(Peruvian and Incaic Phases) at which time through Eocene and early Oligocene time,
siliciclastic-styled deposition dominated the Basin extending. This late sedimentation
episode is represented in the Talara and Tumbes Basins from its current borders, which
originally extended to the north to the Santa Elena area in Ecuador.
Activation of oceanic crust some 26-27 my in the early late Oligocene time created
several regional conditions of which we can mention: a) separation of the oceanic crust
into the Cocos and Nazca plates, b) activation of the Banco Peru/Guayaquil/Dolores
mega shear, c) this later faulting created conditions for the formation of the fore-arc
Tumbes Basin in its present location with beginning of sedimentation since late
Oligocene, and c) complete erosion of the early Oligocene sequences in the Talara
Basin and final uplift to its current location. The continuous deposition since lateOligocene time was punctuated in the Tumbes Basin with similar thick siliciclastic
deposition during a time equivalent duration as in the Talara Basin. Locally, this plate
tectonics migrated the fore-arc basin and sediments provenance northwards to originate
the tectonic depression where the Tumbes Basin was emplaced.
5.2. Geology of the Talara and Tumbes Basins Project Area
Detailed descriptions of the stratigraphy of the Talara and Tumbes Basins will be given
to the reader. This stratigraphy is dominium of staff mostly working in these localized
basins, which extend only into Ecuador and are not like the best-known sub-Andean
24
450000
500000
550000
2J
2K
Z-1
600000
XIX
2T'
9600000
9
2L
Z-38
2N
2M
9550000
9
2O
Z-34
2P
2Q
2H
9
AREA VI
III
2C
2G
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9500000
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Z-6
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9450000
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Z-2B
TUMBE S-T AL ARA BA SINS
GE OLOGI C
AL MA P
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550000
600000
Figure 4: Location Map of Cross Sections in The Talara and Tumbes Basins. Enclosures 2
basins with continental distribution. Enclosures 2a through 2i and Enclosures 2p
through 2s show the stratigraphic sections drilled in the Talara Basin, Enclosures 2j
through 2o does so in the Tumbes Basin and Enclosure 2t is a regional section for the
Talara and Tumbes Basins. The Enclosures in the Talara Basin also includes flattening
in various levels to indicate the basin evolution at various ages. Figure 2 and Figure 3
show the stratigraphic columns in both basins.
25
Sediments of Paleozoic, Mesozoic and Cenozoic age must rest over crystalline
Basement. Since Paleozoic produce oil in two fields in the Talara Basin, we cannot
define Paleozoic as economic Basement in the basin. Locally, it may be considered an
effective Basement.
5.2.1. Basement
Granites drilled by wells PL-X-2 and PL-X-3 in the Carpitas area in the border of the
Talara and Tumbes Basins and in the La Casita 55X in the Bayovar Bay in the south
Talara Basin are assumed to correspond to the crystalline Basement.
5.2.2. Paleozoic
Paleozoic metamorphic rocks and sediments are exposed in the Amotape Mountains and
are known by drilling in the subsurface of the Talara Basin in as far locations as the
Chira sub-basin and Bayovar Bay to the south and the Carpitas area to the north. The
Paleozoic is locally named the Amotape Formation of Pennsylvanian age, possibly
correlating with the Tarma Group of other Peruvian localities. The Paleozoic Sequence
is made up of quartzite, slates and argillites intruded by granite in the Amotape
Mountains.
Prolific reservoirs were found in the Paleozoic section. Production from Paleozoic
mainly fractured reservoirs was established on far extreme onshore locations on the
north Laguna oil field in the Peña Negra High and south on the Portachuelo oil field and
in the recent offshore San Pedro discovery. Detailed descriptions of the Paleozoic
drilled in the Laguna Norte oil field were made since early field development in the 70’s
due to the excellent producing capacity of the metamorphosed Paleozoic sediments.
Paleozoic is covered by shales of Cretaceous age in both onshore Paleozoic fields.
Figure 5, Figure 6, Figure 7, Figure 8, and Figure 9 record the detailed Cretaceous and
Paleozoic sediments drilled in the Laguna Norte oil field. Quartzites are light gray to
white, very coarse to fine grained, sub rounded to subangular grains, fair sorting, with
common quartz overgrowths and quartz veins, locally sugary with primary porosity,
common micro fractures. Oil shows are observed in micro fractures, geodes and pores.
Locally presence of metamorphosed poorly sorted greywacke, dark gray, coarse grained
with silicified detrital matrix. Argillite is black to dark gray, normally with slickensides.
Slate is gray to dark gray, dark gray green with fair to well developed cleavage.
Paleozoic thickness is over 1,500 m. of which 280 m. were drilled in well 2294 the
Laguna Norte oil field (Figure 8).
5.2.3. Cretaceous
Sediments of Cretaceous age are known from outcrops and subsurface. They outcrop on
lapping Paleozoic on the flanks of the Amotape Mountains, bordering the Lancones
Basin and are known in subsurface from drilling in all the Talara Basin. Sediments of
Cretaceous age have been drilled in the Talara Basin since several decades ago, onshore
and offshore. Figure 5, Figure 6, Figure 7, Figure 8, and Figure 9 record the detailed
Cretaceous and Paleozoic sediments drilled in the Laguna Norte oil field. In the
Carpitas area to the north Cretaceous has not been found, since sediments of early
Eocene rest unconformable over sediments of Paleozoic age.
26
Figure 5. Paleozoic and Cretaceous in well EA 1875 in the Laguna Oil Field
27
Figure 6. Paleozoic and Cretaceous in well EA 2114-P in the Laguna Oil Field
28
Figure 7 Paleozoic and Cretaceous in well EA 1885 in the Laguna Oil Field
The sediments of Cretaceous age were deposited in five stratigraphic sequences widely
distributed in most of the Peruvian territory. In the Coastal Region, marine to
continental and volcanic sequences separated from the eastern Cretaceous sub-Andean
sequences by the Marañon Geanticline represent the Cretaceous succession. It is
interpreted that the western extension of the Cretaceous sediments in the Coastal Region
was partially controlled by a Paleozoic and pre-Cambrian? Marginal high, presently
exposed or known as the La Brea/Amotape Mountains, Paita High, Illescas Mountains
and several offshore islands. An incomplete organic rich carbonaceous and siliciclastic
Cretaceous succession with a composite thickness of some 2500 m. extends west of the
Marginal High in the area now occupied by the Talara Basin. The sediments of
Cretaceous age are best known from outcrops in the Amotape Mountains Pazul Creek
(Enclosure 1b), from drilling in the south offshore Chira sub-Basin (Enclosures 2a and
2b), in the offshore Bayovar Bay (Enclosure 2s) and from scattered drilling in the
remaining onshore and offshore Talara Basin (Enclosure 2i). A mainly shale Cretaceous
unit with calcareous imprint constitutes the seal for Paleozoic reservoirs in the Laguna
oil field. Maximum drilled thickness amounts to 283 m. in this field. Similar dark brown
shale with carbonates and conglomerates attributed to the Redondo Formation covers
the Paleozoic Amotape Formation in the Portachuelo oil field.
Three stratigraphic cycles are recognized in the Talara Basin or the NW Coastal Region
west of the Marginal high. Each sequence starts with a basal conglomerate and shallows
upward. The earliest Cretaceous sequence is absent. The oldest sequence in the basin is
Sequence II represented by a regional transgression that deposited the Muerto Pananga
Formations of Albian age. The Pananga Formation onlaps sediments of Paleozoic age,
as observed in the Amotape Mountains. It is made of a basal calcareous sandstone and
conglomerate unit with quartzite and slate boulders changing to reef-type fossiliferous
and neritic crystalline limestones. The sequence culminates with development of
widespread anoxic euxinic conditions characterizing the carbonate Muerto Formation.
The Muerto Formation is characterized by deposition of black, argillaceous,
fossiliferous limestones with strong petroleum odor on fractures and also with pelagic
forams. Total thickness for this sequence amounts to 250 m. representing some 15 my.
of Albian time deposition. Similar organic rich limestones are also observed in the
southern Coastal Region (Pariatambo Formation). It should be mentioned here that the
Raya Formation in the sub-Andean basins correlates regionally in age with the
sediments of the Muerto Pananga Formations.
Black shales, sandstones, occasional black limestones and volcanic rocks of the Copa
Sombrero Formation represent sequence III of late Albian/Cenomanian/Turonian/
Coniacian age. This sequence is restricted to the Lancones and Sechura Basins in
northwestern Peru, east of the Marginal High. A condensed section could represent
sequence III in the Talara Basin.
The Muerto Pananga Formations are separated by an unconformity and overlain by
Sequence IV and V of Campanian/Maastrichtian age representing a transgression that
marks the end of Cretaceous deposition in NW Peru. This upper Cretaceous section is
made up of a siliciclastic interval that starts with the basal conglomerate Sandino
Formation with round shale pebbles in a red to dark brown sandstone matrix underlying
the black to gray and dark brown fossiliferous shales of the Redondo Formation.
Sequence IV ends with deposition of sandstones and shales of the Monte Grande
Formation. Some thicker sandstone and conglomerate units are interbedded with this
32
formation especially in the Chira sub-basin (south Talara Basin) and in the Sechura
Basin where sediment source was close. Maximum thickness for Sandino, Redondo and
Monte Grande Formations are 150, 950 and 300 m. deposited possibly in over 10 my.
Sands, quartz and chert pebbles make up the conglomerates of the Ancha Formation
representing the base of Sequence V of Maastrichtian age. This basal unit rests
unconformable on the Monte Grande Formation and is overlain by shales of the Petacas
Formation. Thickness for Ancha and Petacas is 250 and 750 m. representing some 5 my.
of deposition during Maastrichtian time. In turn, Paleogene sediments superimpose the
Cretaceous section in the Talara Basin and a thick stratigraphic column of Neogene
sediments overlies the Paleogene and Cretaceous, if present, sediments in the Tumbes
Basin.
Sediments possibly from the Redondo and/or Muerto Pananga Formations overly meta
sediments of Paleozoic age in the onshore Laguna Norte and Portachuelo oil fields,
located on the northernmost and southernmost portion of the onshore Talara Basin,
respectively (Figure 5, Figure 6, Figure 7, Figure 8, Figure 9). In the Laguna Norte oil
field, the Cretaceous section consists of a sequence of dark brown shales, marls and
calcareous sandstone. The Cretaceous section provides an excellent seal for the
underlying producing Paleozoic quartzite reservoirs. Maximum thickness drilled is
283m in well 1885 (Figure 7).
South from Portachuelo in the offshore Chira sub-Basin and bordering the Paita High,
Petro-Tech Peruana S.A. is actively exploring the offshore Chira sub-Basin. Drilling in
the 70’s and 80’s discovered a productive Cretaceous siliciclastic and carbonaceous
column in a thick Cretaceous section. Seismic acquired in the late 90’s by Petro-Tech
Peruana S.A. defined over 1200m. of Cretaceous sediments. In all these occurrences the
carbonates of the Muerto and Pananga Formations overly the Paleozoic sediments,
possibly preserved from erosion in original grabens, and now representing inverted
sections. This Cretaceous section overlying the Muerto Pananga Formations consists of
the Sandino conglomerate made of volcanic boulders. Overlying Sandino there is a
thick shale and conglomerate sequence made up of quartzite and volcanics attributed to
the Redondo Formation. Provenance for the Cretaceous succession is very likely to be
the Marginal High described above and represented locally by the Paita High. This
structural high has been active or it has been exposed during the basin history. Well
PHX-A on the flank of this high has Paleozoic with normal poor oil shows underlying
the Salina Formation with all cretaceous section absent and in turn overlain by Verdun
Formation.
Further south in the Bayovar Bay, the La Casita 55X well drilled the following
stratigraphic section underlying a Tertiary Oligocene and Eocene sequence (Enclosure
2s):
? ? Balcones Formation of Paleocene age (top at 2426 m. thickness: 198 m.).
? ? Monte Grande of Maastrichtian age (top at 2621m., thickness: 372m.).
? ? Redondo Fm. of Campanian age (top at 2993m., thickness: 335m.).
? ? All above section overlies what has been described as white quartzites of the
Amotape Formation (top at 3322m., thickness: 6m.) and a Plutonic Igneous
Basement (top at 3328, thickness: 27 m.)
The Monte Grande Formation consists of shales, dark gray, micaceous, carbonaceous
with sandstone streaks white, fine to medium grained, sub rounded, well sorted, quartz,
33
feldspars and quartzite grains. Identified by long ranging Cretaceous-Paleocene forams,
dominated by arenaceous forams found in the overlying Balcones Formation. Some
Cretaceous Redondo Formation micro fauna assemblages occur at the base of the Monte
Grande Formation. Palynilogical determinations of Cretaceous assemblage are also
found in this formation. Mega fauna represents a shallow marine environment probably
deposited in the outer neritic zone. The Redondo Formation is a monotonous thick
sequence of shales dark gray, black and dark brown, micaceous, with calcite grains in
shales, bedded limestones is not present. Abundant suite of arenaceous and calcareous
of the Siphogenerinoides genus predominates in this formation. Campanian-lower
Maastrichtian age is given by the joint occurrence of S. bramletti and S. parva and the
planktonic glumbelina globulosa. The highly foraminiferal contents and assemblages
suggest a single sequence of transgression and regression in a mostly outer neritic
environment.
The end of Cretaceous deposition marks the initiation of the major uplift episode of the
Andean Orogeny. Detailed stratigraphic studies are limited to clearly define the known
Cretaceous succession in the Talara Basin.
5.2.4. Cenozoic
5.2.4.1. Tertiary
The Talara and Tumbes Basins constitute two fore-arc basins each with a very thick
sedimentary section, mostly of different Tertiary ages. The stratigraphy of both basins
described in this report will cover only the portions present in Peru, up to Eocene age in
the Talara Basin and from late Oligocene to present time in the Tumbes Basin. Basin
modeling indicates that an early Oligocene section has been completed eroded in the
Talara Basin.
Sediment source for the Talara Basin to the east deposited from 9,700 to 7,900 m. of
sediments of Paleocene and Eocene ages above the Cretaceous in 30 my. Major tectonic
episodes created accommodations of the Cocos and Nazca Plates and in the South
American Plate overriding the subduction oceanic crust. The primary result was the
changes of sea level and/or uplift of the Talara Basin and the formation of the Tumbes
depression that migrated the geographical basin or sediment source for the Post-Eocene
sediments northwards to a depression that created the Tumbes Basin. The Tumbes Basin
was also the site of very rapid sedimentation of 6,600 m. offshore to 7,200 m. onshore
of Oligocene, Miocene and Pliocene sediments in 35 my. The Tumbes and Zarumilla
Rivers in the Tumbes Basin have currently very active delta fronts near the Ecuadorian
border and also smaller creeks carry enormous amounts of sediments into the offshore
Talara and Tumbes Basins. Similar proto Tumbes- and Zarumilla-like Rivers possibly
were also very active carrying sediments to the Talara Basin during Eocene time before
they migrated to their actual location. The stratigraphic descriptions for the sequences of
each basin will be treated separately, since age of sediments vary notably from one
basin to another.
5.2.4.2. TALARA BASIN
In the Talara Basin, the Tertiary Paleocene and Eocene stratigraphic sequences includes
sediments from Cone Hill to Mesa Formations (Figure 2). The composite overall
thickness of 9,700 m. decreases to 7,900 m. from the south Talara/Portachuelo area to
the Peña Negra area to the north. A very thin section, 500 m. between Oligocene and
34
Basement observed in seismic can be attributed to a section of comparable age in the
southern offshore Tumbes Basin. The Tertiary section in the Talara Basin was deposited
in four major sequences of third order comprising one of Paleocene and three of Eocene
ages.
? ? Paleocene Sequence
Early Tertiary sedimentation began with deposition of the Mal Paso Group of Paleocene
Danian age unconformable overlying the Cretaceous Petacas Formation. The Paleocene
Mesa and Balcones constitutes the basal and oldest Tertiary sequence. Previous
literature extend down in time the Mal Paso Group to include Cretaceous Sequence V
Ancha and Petacas Formations, but in this report the group will only refer to the
Paleocene Mesa and Balcones Formations. It should be noted, however, that in some
portions of the Talara Basin there existed a rather continuous deposition and transition
with relative short time breaks during deposition of the late Cretaceous and early
Tertiary Paleocene sequences containing the Redondo, Petacas and Balcones
Formations, all of them with similar lithology.
The Mal Paso Group partially outcrops in the Paita High area, although is best known in
subsurface. The group is made up of the basal sandy Mesa Formation underlying the
Balcones Formation black shales rich in foraminifer micro fauna. Thickness of the Mal
Paso Sequence is 2,000 m. deposited in some 9 my in the south Talara Basin, where is
best known.
? ? Eocene Sequences
By far the Eocene section constitutes the most important producing interval in the whole
Talara Basin. It consists of three stratigraphic sequences totaling some 7,700 m. to
6,000+ m. from south to north where the upper Eocene is mostly absent. Each sequence
consists of a basal conglomerate followed by a succession of interbedded silty clays and
shales and feldspatic sandstones.
The basal Sequence I is of early Eocene age, the 2nd. Sequence II includes the middle
and early upper Eocene and the 3rd sequence III is of middle to upper Eocene age. All
these stratigraphic successions outcrop almost completely in the Negritos area. Notable
thickness and stratigraphic variations and lower order sequences are interpreted in the
Eocene sediments. To complicate even further the regional and local distribution of the
many stratigraphic units is the contemporaneous deposition and deformation causing
hundreds of normal faults with few to hundreds of meters of stratigraphic throws that
make the absence of units to be interpreted as stratigraphic variations.
o Eocene Sequence I
The general stratigraphic relationship between the different formations of the Early
Tertiary Sequence I in the Talara Basin is shown in Figure 10. This figure comes from
internal International Petroleum Companies files from the 60’s. and has been the basis
for many reports published in the last decades. Deposition of Tertiary sediments starts
with a basal conglomerate or Salina Basal (Trigal Formation in the Carpitas area)
discontinuously over a locally conformable surface of the Paleocene Balcones
Formation, to whom it resembles lithologically. A shale facies or San Cristobal
Formation overlies the Salina Basal Formation. The whole lower portion of the
sequence is also seen to overlap upper Cretaceous sediments to the east of the basin. In
general, this lower portion of the sequence has a more marine shale facies followed by
35
the sandier upper facies of the Salina Formation. The Salina Formation with sandy and
shale character in the south Talara Basin becomes the coarse and conglomerate
Mogollon Formation of the north Talara Basin. Conformable overlying the Salina
Formation is the Palegreda Formation, a thick dark, soft, weathering to pink color,
fossiliferous shales and few sandstone interbeds, which also changes to a more
sandstone character to the north as the Ostrea Formation (Figure 10).
Terminating deposition of Sequence I are the Pariñas and Chacra Formations overlying
the Palegreda Formation. The Pariñas Formation extends south down to the offshore
Chira sub-Basin (well NPXB-24X, Enclosure 2a), where the Pariñas wedge is fault
controlled by the post-Cretaceous North Paita Fault (Petro-Tech, 1999). This is a NW
dipping fault trending SW-NE offshore; the Pariñas wedge extends onshore and crosses
the NW portion Portachuelo Field. The Pariñas sands are fine to conglomeratic,
quartzose, with good sorting, with few shales interbeds; petrified fossil logs 0.5m. in
diameter and 6 m. long were found in this formation. This unit may be subdivided into
two units. The main difference is the shale character of the lower unit with poorer
reservoir quality. In the northern Talara Basin the Pariñas Formation is time equivalent
to the Clavel and Cabo Blanco Formations. This latter formation is characterized by a
fluvial-deltaic facies of coarse sandstone and conglomerates deposited in channels
caved on the Clavel Formation. The end of Sequence I is marked by deposition of the
Chacra Formation conformably overlying the Pariñas Formation. The Chacra Formation
consists of dark green gray shales wit a fossiliferous lower section capping conformably
the Pariñas Formation. The formation changes to a sandy facies to the north, where the
Echinocyamus Formation was deposited as the end of Sequence I. Total composite
thickness for sequence I amounts to 2,700 m. in the south increasing considerably to
4,500 m. to the north Talara Basin. This considerable thickness defines a period of rapid
sedimentation in 5 my during early Eocene time.
o Eocene Sequence II
Sequence II of Middle Eocene and early upper Eocene age is made of the Talara Group
unconformable overlying the Chacra Formation and on lapping all the lower Eocene
units in different parts of the basin. The group has the basal Lomitos Conglomerate/
Terebratula Sandstone Member discontinuously distributed over the basin and overlain
by the thick Talara Shale, a fossiliferous unit with characteristic rubble zone produced
by contemporaneous deformation. The Talara Shale carries the imprint of gravity
sliding of enormous blocks, episodes that created zones with common repetition of
various formations. The Talara Shale grades upwards into the sand and shale unit of the
Talara Sandstone and finally the light gray shales Pozo Shale ends the sequence. The
turbidite sandstone and conglomerate Helico Member develops as a prolific oil producer
in some areas as the Carrizo pool in current Block X. Thickness of Sequence II reaches
2000 m. deposited in 12 my in the south Talara Basin; this thickness decreases to 600 to
the north, where the Talara Sandstone and the Pozo Shale are absent after a period of
considerable erosion at the end of the middle Eocene.
o Eocene Sequence III
Sequence III consisting of the basal Verdun Formation overlain by the Chira Group
characterizes the end of Eocene deposition. The coarse quartzose sandstones of the
Verdun Formation was deposited unconformable and on lapping the Talara Group and it
is overlain by the basal unit of the Chira Group or Chira Formation, with good exposure
in the Chira River valley to the south of the Talara Basin. The lower section of
36
MIDDLEEOCENE
LOWEREOCENE
PA
L
EO
CE
NE
LOBITOS
OSTREA
CLAVEL
CABO BLANCO
............................................
.......................................................................................
ECHINOCYAMUS
................................................................
TEREBRATULA
HELICO
BALCONES
NOTTO SCALE
FACIESBOUNDARY
UNCONFORMITY
STRATIGRAPHIC RELATIONSHIPS OF THELOWER& MIDDLEEOCENEROCKSIN NORTHWESTERN PERU
DOMINANTLYSANDSTONE
SHALE
BASALSALINA
LOWERSALINA
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UPPERSALINA
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MOGOLLON
MANTA
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PALEGREDA
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PARIÑAS
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CHACRA
Lomitos Conglomerate
Quemada Zone
HELICO
MONTE
HELICO
PA
L
EO
CE
NE
Tala
r
a
Sha
le
SALINA
MIDDLEEOCENE
LOWEREOCENE
Prieta Rica Zone
Sequence III has a more regional distribution than the overlain shale, sandstone and
conglomerates of the Mirador Formation and the shales of the Cone Hill or Carpitas
Formation. The Verdun Formation extends to the Sechura Basin to the southeast, where
IPCo discovered dry-gas accumulations in the 50’s. This old discovery is being
developed commercially by Olympic in Block XIII since the early 2,000’s. Composite
thickness for Sequence III deposited in 4 my. is nearly 3,000 m. in the southern area,
whereas it only reaches some 1,300m in the Carpitas area to the north.
Figure 10. Stratigraphic relationship in formations of early Tertiary age in the Talara Basin.
37
? ? Pleistocene
The Tablazo Formation caps the Tertiary sediments west of the Amotape Mountains in
the whole Talara Basin. This formation consists of marine calcareous, coquina and very
fossiliferous sands overlying sediments of Paleozoic, Cretaceous and Tertiary age. It
represents the last stages of sea level changes that left marked erosion surfaces. The
Tablazo forms the Talara and Mancora Tablazos, two main distinctive flat to almost
horizontally lying topographic units bordering the southern Amotape Mountains east
and northeast of the Lagunitos Graben and east of the Negritos Talara High, as seen on
the geologic map (Enclosure 1d). The Tablazos are interpreted to absorb most sound
waves that causes poor seismic response in the basin.
5.2.4.3. TUMBES BASIN
The Tumbes Basin extends onshore and offshore to the north and adjacent to the Talara
Basin and continues past the country border as the Progreso Basin in Ecuador.
Sediments of late Oligocene, Miocene and Pliocene age are more representative of the
Tumbes Basin, where a thick stratigraphic column outcrops completely and it is known
by drilling and seismic data to extend offshore (Figure 3). Sediments were deposited in
at least five stratigraphic sequences resting unconformable over Eocene sediments. The
oldest sequence is observed to outcrop onlapping progressively older formations of late
and middle Eocene age and Amotape Formation from the Mancora area to the northeast.
The Higueron Intrusive intrudes the Tertiary sediments and the Paleozoic Amotape
Formation in the NE border of the basin. Thickness of the Oligocene to Pliocene
column varies from 7100 m. onshore to 6200 m. offshore, all the section deposited in
approximately 30 my.
The Banco Peru is seen as a high-density sea mound based on gravity anomaly analysis
with dolomite on its margins and evidence of seismic stratification (Shepherd and
Moberly, 1981). Presences of a Cenozoic section and possibly a Paleozoic section have
been interpreted on Seismic on the current report (Figure 16). Commercial oil
occurrence in metamorphic Paleozoic reservoirs in extreme localities in the south and
north Talara Basin makes this tectonic feature larger than the Talara Negritos High
(over 600 MMBO produced) extremely important for hydrocarbons exploration.
? ? Oligocene and Miocene
The basal Sequence I represents a major transgression episode that deposited littoral,
near shore and deltaic sediments. This sequence is characterized by great basin
subsidence or high sea level rise on the current onshore portion of the basin; thickness
onshore greatly exceeds thickness offshore. It starts with deposition of the Mancora
Formation of late Oligocene to early Miocene age followed by the Heath Formation of
early Miocene age. The Mancora Formation consists of sandstones and shales with a
basal unit or Plateritos Member made up of a 40-m. thick quartzose and quartzitic
sandstone and conglomerate unit with medium to coarse friable sand matrix and
varicolored shales. Sequence I ends with deposition of the organic-rich dark brown to
light gray shales, siltstones and some limestones and marls in the upper part of the
Heath Formation overlying the Mancora Formation in transitional contact. Sequence I
thickens considerably onshore and is considered one of the main objectives in the
Tumbes Basin.
38
The Zorritos Formation of early Miocene age constitutes Sequence II that ends a period
of rapid thick deposition with minor time breaks. The unit is characterized by deposition
of coarse fluvial, deltaic and near shore sandstones and conglomerates with
subordinated varicolored shales. This unit is the main reservoir in the basin and also in
the offshore Amistad field across the border in Ecuador.
The end of deposition of Sequence II during late early Miocene time is followed by a
period of sea level fall and erosion of the exposed Zorritos Formation. Deep incised
valleys and channel fill sediments are readily distinguished by seismic to correspond to
shales of the overlying Cardalitos Formation, or Sequence III deposited unconformable
over the Zorritos Formation. Shales of Sequence III were deposited over a very
distinctive erosional unconformity, readily distinguished in the basin by proliferation of
numerous deep channels. Deltaic and littoral sediments make up the Tumbes and Mal
Pelo Formations overlying unconformable the Cardalitos Formation. Each of these
formations shows certain degree of erosion or unconformable contact with each other
making up individual sequences IV and V. The Tumbes Formation or Sequence IV
makes, a marine shallow water coarse clastic deposits onshore grading to fine sands and
shales offshore. The late Miocene Sequence VI or Mal Pelo Formation is characterized
by deposition of a thick coarse clastic section.
The Tumbes Basin is capped by deposition of shale of the Pliocene La Cruz Formation
or Sequence VII. This sequence shows local erosion over structurally high areas of the
underlying Sequence VI at the base of this formation and the development of sintectonic
deposition over growth faults.
5.3. Regional Tectonics Settings
This chapter summarizes a more detailed geological and geophysical analysis of the
Talara and Tumbes Basins included in Spanish as Appendix 3 (Análisis de la Geometría
y Estilo de Deformación de las Cuencas de Antepais Talara y Tumbes).
The Talara and Tumbes basins correspond to a forearc basin system developed along
the northern coastal Peruvian Andes during Paleogene and Neogene times. The modern
structural configuration is related to a complex geodynamic history associated with the
interaction of the tectonics, eustatic and sedimentary processes that is controlled by the
direction and velocity of the relative subduction of the oceanic crust, the aseismic
subduction ridge and principally by the Andes Mountain building.
The Tumbes basin is bounded on its ocean ward side by a subduction complex wedge
and on its landward side by the Amotape Mountains (Figure 11). The main tectonic
elements that control the tectono-sedimentary evolution of the Tumbes basins are as
follows: i) the western regions of the Tumbes basin is controlled by the Banco Peru
structure, whose eastern border is limited by the Banco Peru fault, a southern projection
of the Dolores Guayaquil - Puna Pallantanga megashear. ii) the eastern region of the
Tumbes Basin is controlled by the Zorritos – Piedra Redonda High and the Amotapes
Mountains (Figure 11).
The eastern limit of the Paleogene Talara Basin is given by the La Brea Hill and
Amotape Mountains, which separates the basin from the Lancones basin. The southeast
boundary corresponds to the transition of the Neogene Sechura Basin. In the offshore,
the western portion of the Talara Basin is comprised of two marine platforms (deep and
shallow platforms), controlled by listric normal faults and ends in an accretionary
wedge adjacent to the oceanic trench.
39
The Talara and Tumbes forearc basins are deformed by extensional fault-bend fold and
gravitational tectonics, forming the curved and planar rollover structures and gravity
slides associated with listric normal faults (Figure 11).
The fill of the Talara and Tumbes basins is characterized by different stratigraphic
sequences associated with significant tectonic events, which generated erosional
surfaces, changes in the depositional environment, rate of sedimentation and depocenter
migration. The stratigraphic architecture reflects shifts in basin accommodation space,
which derives from the interplay of extensional tectonics, sediment supply, and eustatic
sea level acting upon the arc-trench gap. The internal sequence architecture shows the
retrogradational, progradational and agradational stacking pattern (Figure 11).
Figure 11: Morphological and structural configuration in the Andean Cordillera, showing
the Talara and Tumbes forearc basins.
5.3.1. Geometric and structural analyses of the Talara and Tumbes forearc
basins
The geometric and structural analysis of the Talara and Tumbes basin is based on
seismic interpretation, well correlation and regional tectonic setting (Figure 12). The
seismic lines in two way time (TWT) have been calibrated by synthetic seismograms
generated by Log Edit software. The synthetic seismograms correspond to acoustic
impedance and coefficient reflection calculated from the sonic and density log.
The seismic interpretation, regional mapping, and well data have been integrated in
twelve offshore seismic sections and three offshore to onshore regional cross sections in
the Talara and Tumbes basins (Appendix 3 and Enclosures 3a to 3p). A detailed
analysis of the seismic data allows the identification and characterization of the tectonic
structures with their associated fault geometries, the erosional surfaces, channel
geometries, lateral changes of sedimentary facies, such as growth strata, onlaps,
downlap, toplap geometries and truncations. The integration of this data can be used to
predict the geometry and style of deformation of the tectonic structures and the potential
for significant hydrocarbon accumulations in the Talara and Tumbes basins.
40
Figure 12. Geological and structural map of the onshore portions of the Tumbes and Talara
basins and adjacent areas, showing the location of interpreted seismic lines in red and
regional cross sections, referred to in this chapter.
The geometry and style of the deformation of the Talara -Tumbes Basins and their
structural and stratigraphic components relative to hydrocarbon exploration are
explained in Appendix 3 and Enclosures 3a to 3p.
5.3.1.1. Tumbes Basin
The structural style of the Neogene Tumbes basin is largely a result of a NW regional
tilt associated with the Banco Peru Fault, which is the southern edge of the DoloresGuayaquil megashear zone (Figure 13). It has resulted in gravitational tectonic
structures, which have generated curved rollover and planar rollover anticline structures
and some rotated fault blocks. These structures are associated to listric normal faults
dipping to the NW with detachment level located in the base of the Heath Formation
and Pre Mancora series (Figure 14, Figure 15, Figure 16, Figure 17 and Figure 18).
The major period of development for these gravitational structures occurred during the
deposition of the Mal Pelo and La Cruz formations (Pliocene Pleistocene times). In the
present time, the Tumbes basin corresponds to a major half graben controlled by the
41
Banco Peru Fault. Many of the structures in the Tumbes basin are currently active as
indicated by the recent deformation of the younger sedimentary deposits.
The Tumbes Basin has numerous excellent leads and tectonic structures that represent
excellent opportunities for hydrocarbon exploration. This potential is related to the
combination of the rollover anticline structures and subcropping plays at the base of the
Cardalitos Formation (Chita, Lenguado, Perico, Raya, Jurel, Merluza and Corvina type
leads). The classic primary reservoir target in the basin corresponds to the Zorritos
Formation. In this study, we propose a deeper target in the Mancora, pre -Mancora and
Eocene formations. This objective has been identified within the Deeper Delfin lead and
the Zorritos Piedra Redonda High (Figure 14, Figure 15, Figure 16, Figure 17, Figure
18, Figure 19).
Figure 13. Structural map of the Tumbes basin and northern part of the Talara basin. For
more details see Appendix 3 and Enclosure 3m.
Figure 14. Seismic interpretation of the line PC 99-01, showing the gravitational structures
associated with the Corvina and Barracuda structures. In the Corvina structure note, the
importance of the rock units subcropping the base of the Cardalitos unconformity with
respect to hydrocarbon exploration. More details can be found in Appendix 3 and Enclosure
3a.
42
Figure 15. Seismic interpretation of the line AIP 92-49, showing the Delfin structure with its
deeper Lead and the Lenguado lead. More details can be found in Appendix 3 and Enclosure
3c.
Figure 16. Seismic interpretation of the regional seismic line RIB 93-01, showing the main
tectonic elements of the Tumbes Basin. The Banco Peru is on the left and the Tumbes Basin
on the right. This seismic interpretation shows two potential prospective structures, the Chita
and Paleozoic Banco Peru leads. More details can be found in Appendix 3 and Enclosure 3c.
Figure 17. Seismic interpretation of the line AIP 92-30, showing the Zorritos Piedra Redonda
High to the right, the Deep Piedra Redonda Lead associated with the Eocene series and the
Perico and Raya leads to the left. According to the structural and seismic interpretation, the
Zorritos – Piedra Redonda High is part of a present-day SW- NE horst structure. The western
flank (offshore) of this feature is defined by the SW-NE trending Tumbes and Piedra
Redonda normal listric faults. The eastern flank (onshore) of this structure is defined by the
SW- NE trending Tronco Mocho, Cardalitos and Carpitas normal fault system, which dips to
the SE. This fault system is related to the ancient structural configuration of the Paleogene
Talara basin that was reactivated during the Neogene.
43
Figure 18. Seismic interpretation of the line AIP 92-12, shows the western boundary of the
Zorritos Piedra Redonda High and the Jurel and Perico leads. These structures appear to
have considerable potential as exploration targets. More information can be found in
Appendix 3 and Enclosure 3e.
5.3.1.2. Talara Basin
The present-day structural configuration of the Talara Basin is the result of complex
extensional and gravitational tectonics that occurred during Paleocene and mainly
during middle Eocene times, with reactivation in Neogene time. The Talara Basin
overlies a larger morphological configuration of Cretaceous and Paleozoic tectonic
events.
The structural style of the Paleogene Talara Basin is characterized by normal faulting,
as well as low-angle gravitational faults and large vertical transcurrent faults. This
tectonic style has resulted in a number of rollover anticline structures, rotated fault
blocks and growth faulting associated with deep listric normal faults. The detachment
level is located within the Paleozoic and Basement (Figure 19, Figure 20, Figure 21,
Figure 22, Figure 23 and Figure 24).
According to regional mapping and seismic interpretation, faulting is more intense in
the onshore portion and shallow offshore platform of the Talara Basin. A regional crosssection in the northern part of the Talara and Tumbes Basins indicates a regional tilting
to the west (Enclosure 3o).
The sedimentary fill of the Talara Basin is controlled by structural deformation that has
produced a complex clastic sedimentary sequence with a wide variation of formation
thicknesses throughout the basin. The synsedimentary extensional tectonics is
represented by rollover anticline structures associated with high and low-angle listric
normal faults. The relative movement of the listric normal faults is directly related to the
configuration of Paleozoic and Basement rocks (Figure 19, Figure 20, Figure 21, Figure
22, Figure 23 and Figure 24).
Structural, stratigraphic traps and combined structures with high potential for the
hydrocarbon exploration have been identified in the Talara Basin (Figure 19; Figure 20,
Figure 21, Figure 22, Figure 23 and Figure 24; Enclosures 3g to 3l). On the deep
offshore platform, we have interpreted the new Mero and Tiburon leads related to
rollover anticline structures. On the shallow platform of the Talara Basin we find many
structural and stratigraphic features, essentials for the hydrocarbon exploration as the
Calamar, Caballa rollover anticline leads, the Deeper Paleozoic Lobitos lead and the
Paleozoic lead.
44
The geometry and style of the deformation of the Talara Basin and structural and
stratigraphic potential for hydrocarbon exploration are explained in Appendix 3 and
Enclosures 3a to 3p.
Figure 19. Seismic interpretation of the line RIB 93-01. This section shows the shallow and
deep platforms, where the Merluza and Mero rollover structures developed with high
potential for exploration. More details can be found in Appendix 3 and Enclosure 3g.
Figure 20. Seismic interpretation of the line RIB 93-08, showing the potential of the offshore
tectonic structures in the shallow and deep marine platforms. The Deeper Lobitos lead is
defined to target the Paleozoic series in direct contact with potential Cretaceous and Lower
Tertiary source rocks. The Tiburon lead corresponds to new structural leads in ultra deep
waters. More details can be found in Appendix 3 and Enclosure 3h.
Figure 21. Seismic interpretation of the regional line RIB 93-16, showing the tectonic
elements of the Talara basin. On the left, the subduction trench is seen where the oceanic
crust pass under the continental crust. On the right, the shallow platform shows the Calamar
rollover structure and the Paleozoic lead. Potential exploration targets in interpreted kitchen
areas. More details can be found in Appendix 3 and Enclosure 3i.
45
1.26
1.66
LA CRUZ Z5205
1.55 1.73
DELF B 5X
DELF B 11CD
1.35
1.44
CORRAL EPRCX1
1.35
RT 59
ZORRITOS RT 48
1.87 2.05
RT 50
2.20
RX67
1.84
PIEDRA RED 14X
PIEDRA RED 13X
1.74
1.17
T RIGAL T RX1
0.79
PLAT ER PL X2
1.37
PLAT ER PL X3
CARPIT AS C115
2.23
BARRANCO BAX1
CAPILLA CX 2
T X 35
1.42
1555
ORXA 13X
CAPILLA CX 1
2239
1.85
1.33
5630
2010
1.85
1875
XX 11X
T 17
5380
1.41
1.53 1.67
1910
5655
1.30
1.53
1.80
0.55
PN1 12X
1540
5665 5680
AA 18X
LL 115 0.99 1.89 1.32
PN8 17X
1860 1865 1.57
1545
1.52 1.34
1.62 1570 1740 1.46
DD
12X
PN3 11X PN2 8X
56681.741.40
1.34
SICH 61X
CEREZAL CEX1
AT ASCADERO 1X
1.19
1.18
1.68
1.87 1.44 1.10 1.53
2.06
1725
1.49
5080
CARRIZO 1980
2.51 1.43
LO6 13X
5505
1.36
4690
5340
1.30 1.35
1.25
T 14 1
1.64
2.46
OLLOCOS OX- 2
1855 AX25
MISC SAL 5135
1.20
1.24
1.64
H5S X10
A3 22X
1.07 1.67
1.84
1.48
LO5 13X
LO1 9X
LO3 22X
6035
6060
1940
131
CC X15
1.53
FONDO 4800
H7 X3
1.07
LO10-7X
LO10 20A
1.28 A1 6X
5X
1.11 A1
A1 8X
1.51
1.70
H9A X1
0.78 0.91
1.55 1.74
4875
ALV OVE 4835
1.66
ALV OVE 3885
1.22
2.26
MLX9 15X
1.08
8A X1
0.64
7B X1 1.59
1.46 PV15 10
7B X2
1.63
A4 19X 1.08 6B X1 PVX13 6
PVX8 13X
1.45 1.461.57 1.99
1.53
P26B X1
4120
2.64
4000
3835
1.67
1.64
4015
2.13
2.81
NHX1 7X
NHX1 19X
1.25
NHX 6
.67 NHX 4 1.32
0.61 NHX 2B 3 X4 EE X3
0.78 1.54 LT 8 11X
NHX 7
A5 9X
NHX 5
1.84 1.57
0.54 1.28
EX6 6X
EX6 2X
1.77EX6 8X
1.79
5325
1.49
5565
1.72
EX4 15X
1.52
NPXB-24X
1.25
10
0
10
20
30 km
Figure 22. Seismic interpretation of the line RIB 93-21, showing the Bayovar Bay bounded
by the Illescas and Paita Highs. The Bayovar Bay illustrates the many structures associated
to rollover anticline structures. According to seismic and structural interpretations, these
structures show high potential for exploration. More details can be found in Appendix 3 and
Enclosure 3j.
Figure 23. Seismic interpretation of the line PTP 99-23, located in an area where the Talara
to Sechura Basin merge. It shows the San Pedro and East San Pedro structures. More details
can be found in Appendix 3 and Enclosure 3k.
Figure 24. Seismic interpretation of the line PTP 99-24, this section is located in an area
where the Talara merges with the Sechura Basin. It also shows the San Pedro and East San
Pedro structures. More details can be found in Appendix 3 and Enclosure 3l.
5.3.1.3. Posters
During preparation of this study the Basin Evaluations Group prepared a series of five
technical posters to support Perupetro S.A. promotion overseas (Enclosures 5a to 5e).
Enclosure 5a is a Digital Elevation Model DEM to a resolution of 90 m that includes the
sedimentary basins and the various current hydrocarbon exploration licensees, TEA’s
and PEA’s. Enclosure 5b is a morphological/structural configuration of the Andean
Mountains showing the oceanic Nazca Plate, subduction trench and the south Talara
forearc Basin at the Bayovar Bay to the west. To the east the cross section shows the
retroforeland basin system (Huallaga and Marañon Basins) with the eastern fore bulge
represented by the Iquitos Arch. The forearc and retroforeland basins are the sites of
current intensive hydrocarbon exploration, with the interpreted hydrocarbon kitchen for
the 2005 oil discovery San Pedro in the former. Enclosures 5c to 5e show geologicalwell-seismic interpretations defining the structural style of the Talara and Tumbes
Basins and the various prospects and leads in different portions of the basins.
46
6.0. GEOPHYSICS
6.1. Seismic Data
The seismic interpretation is based on 9,814.55 km. of offshore 2D seismic in SEG-Y
format from six seismic campaigns listed in Enclosure 6 in Digital Form and shown in
Figure 25. Thirty seven (37) synthetic seismograms from selected wells, only one
onshore in the Talara Basin, were prepared to tie the seismic interpretation in both
basins.
TUMBES BASIN
TALARA
BASIN
Figure 25. Seismic reference map.
The digital seismic data utilized in the study was provided by of Perupetro Data Bank.
Usually the data as given to GFEC, was as received by Perupetro from the operating
company that acquired it. The data quality in the Talara and Tumbes study area is very
good. Time shifts between surveys and lines of the same survey are also of very good
quality with no big miss ties problems.
The type of seismic processing differs from survey to survey. There is one survey
reprocessed using AVO (Amplitud Vs Offset) process of American International
47
Petroleum Corporation survey (AIP-1992) and the other surveys correspond to normal
reprocessed seismic by Petrotech (1999-2000).
The selected seismic events used in the stratigraphic and structural interpretation
include the following:
1. Top Mal Pelo Formation Upper Miocene, Tumbes Basin.
2. Top Zorritos Formation Lower Miocene, Tumbes Basin.
3. Top Middle Eocene in the Talara and Tumbes Basins used for regional
correlation.
4. Top Cretaceous in the southern Talara Basin.
5. Top Muerto Formation Middle Cretaceous in the Talara Basin.
6. Basement.
The following structural maps were prepared on this stage of the project (Enclosures 3a,
3b, 3c, 3d and 3e):
1. Top Middle Eocene in the Talara and Tumbes Basins.
2. Top Muerto Formation with presentation of selected seismic lines in the
southern Talara Basin.
3. Top Zorritos Formation in the Tumbes Basin.
Final presentation will define prospects and leads within and outside current production
blocks.
6.2. Airmagnetometry and Air gravity
Petro-Tech Peruana S.A. (2001) acquired 5,400 KM Airmagnetometry and Air gravity
and 18,500 km of high-resolution Airmagnetometry in 1997 to integrate the information
between known productive areas and prospective undeveloped areas in the license
contract Block Z-2B. A Petro-Tech Depth to Basement based on the Airmagnetometry
and Air gravity interpretation is presented in Figure 26.
A correlation between productive structural highs and structural noses and potential
adjacent deep areas considered as kitchens is established suggesting short distance
hydrocarbons migration. The known deep onshore grabens with thick sediments of
Tertiary and Cretaceous age in between the three major structural highs in the Talara
Basin are clearly seen to extend offshore in the High Density or Depth to Basement
Maps. The delineation and position of these potential kitchens also suggest potential
larger distance hydrocarbons migration to the three major structural highs from not only
one but from all surrounding deep areas.
The extension of the three major structural highs of the Talara Basin and of the Paita
High from onshore to offshore past the western border of the Block Z-2B is evident on
above maps. A high-density anomaly runs NE-SW off the eastern border of the block
west of the Peña Negra High. Two N-S anomalies are also seen west of the Negritos
Talara High and to the SW of Negritos. The latter anomaly is mostly across the northern
Lagunitos Graben. Two more anomalies are defined WNW and to the WSW of the Paita
High.
48
Figure 26. High Density Basement Map in NW Peru (Petrotech, 2001).
49
7.0. PETROLEUM GEOLOGY
7.1.Geochemistry
7.1.1. General Discussion
Few modern Geochemical studies have been conducted in the Talara and Tumbes
Basins and in the neighboring Trujillo, Sechura and Lancones Basins in an attempt to
define the petroleum systems present in the northern Peruvian coastal basins. The effort
so far is incomplete to clearly recognize all the elements responsible for the giant oil
accumulation in the Talara Basin and the different hydrocarbon occurrences in the
Tumbes Basin. Presence of multiple reservoirs in the stratigraphic column mainly in the
Eocene sediments of the Talara Basin, the main producing interval in the coastal basin,
made the studies to be considered of less importance until the 90’s. Several companies,
among them Perupetro (1999), Perez Companc (2000), Repsol (1996), UPPPL (1993),
Mobil (1993), Petro-Tech Peruana S.A., and more recently a group of researchers of
Stanford University with logistic support from Petrobras (operator of Block X in the
onshore Talara Basin) have performed Geochemical analyses on oil samples and
outcrops in northwestern Peru (Fildani, A. et.al. 2005). The Perupetro study made a
good attempt to fill a major gap conducting its modern Geochemical evaluation that
included all coastal and offshore basins.
The studies cover geochemistry analyses to evaluate potential source rocks and oil
characterization to make oil-oil and oil-source rock correlations and some basin
modeling to establish maturity levels and timing of hydrocarbons generation and
migration. For a more comprehensive understanding and for detailed information of
these reports the reader is referred to the Geochemical reports and database in the
Perupetro technical archives. This technical archive contains listing of the Geochemical
reports in its files produced by the several oil companies that were active in exploration
and development in these various basins in the last decades. Detailed results of all these
Geochemical studies are incorporated below, since the present study has not performed
any of these analyses.
Among the several uncertainties drawn from the major conclusions from these reports
are:
1) There is no general agreement as to the identification of the active source rocks
for the oils in both basins; oil-source rock correlation with samples from wells
and their outcrops in the basins and with outcrops from neighboring basins have
provided good and in some cases disappointing results. An exceptional good
match is found for the correlation between a Gas Chromatograms from a
representative oil sample of the Talara Basin and from a bitumen extract of the
Heath Formation of the Piedra Redonda C-13X well interpreted as part of the
Tumbes Basin (Figure 27).
2) There is also no well-defined knowledge of the location of hydrocarbons
kitchens and timing and migration routes for the known hydrocarbon
occurrences in both basins. Maturity levels and organic matter distribution imply
a medium to long-range migration routes from the source rock kitchen areas to
reservoirs for the accumulations found to date. The geological events placed in
assumed local kitchens as in the Lagunitos and Siches grabens do not fully
account for the hydrocarbons found in the three major tectonic highs in the
50
Talara Basin, which are complexly faulted with sealing faults. Age of and the
tectonism itself may have also prevented postulated migration from kitchens of
post-Eocene source rocks in the deep Tumbes Basin to the Talara Basin
reservoirs.
3) All oils analyzed apparently correspond to a common origin, possibly pointing
to a single oil family, especially in the Talara Basin. It is recommended for
future studies that oil sampling must state production level to clearly indicate
which reservoir the oils come from, since most wells have multiple reservoirs.
Lack of oil or gas samples from the offshore wells in the Tumbes Basin prevents
to conduct Geochemical analyses in the Tumbes Basin, as it was the case faced
by Perez Companc S.A. (now Petrobras Energía del Perú S.A.) in the Evaluation
of Block Z-1 in year 2,000.
Talara oil
Intensity
Oleanane
Time
Intensity
Piedra Redonda C-13X
Formación Heath
10,600-10,700’
Time
Figure 27. Correlation
between GCMS of a
representative oil sample
from the Talara Basin
and from an extract of a
cutting sample of the
Heath Formation in the
Piedra Redonda Field
(Fildani, 2005).
The Perupetro S.A.
report includes an Excel
Geochemical database
compiled with newly
acquired data and all
available data of the
coastal basins in the
Perupetro files. The
portion of this database
for the Talara and
Tumbes Basins are
included as Appendix 1
on the present report;
and it also includes the
geochemical data from
the adjacent Lancones
and Sechura Basins,
since some formations are strongly genetically related.
A summary of geochemical data categorized by age of the potential hydrocarbon source
rock is given in the following sections.
7.1.2. Source Rocks and Maturity
There are numerous analyses of the quality of organic matter and less analyses of
vitrinite reflectance, Ro indicator, to identify the source rocks and maturity levels in
several formations in both basins. Descriptions of samples analyzed are included below
under the previous studies and a tabulation of them is presented in Appendix 1.
51
Based on available geochemical information the following formations from Cretaceous
to Tertiary age can be identified as main potential source rocks in the Talara and
Tumbes Basins.
Tertiary
? ? Miocene Cardalitos Formation in the Tumbes Basin.
? ? Miocene Zorritos Formation in the Tumbes Basin
? ? Oligocene/Miocene Heath Formation in the Tumbes Basin
? ? Oligocene Mancora Formation in the Tumbes Basin
? ? Eocene Formations in the Talara and Tumbes (?) Basins.
? ? Paleocene Formations in the Talara Basin
Cretaceous
? ? Redondo Formation of Campanian-Maastrichtian age in the Talara Basin
? ? Muerto Formation of Albian age in the Talara Basin and Lancones Basin.
? ? The extension of the Cretaceous section into the Tumbes Basin is unknown.
Paleozoic
? ? The Paleozoic sedimentary section consists mainly of a metamorphosed with
clear indication of post-maturity conditions.
7.1.2.1. Tertiary
Potential source rocks of Tertiary age are limited to the Paleocene and Eocene
sequences in the Talara Basin and from the Eocene (?) to Miocene sequences in the
Tumbes Basin. Oligocene sequences are likely to constitute the final sedimentation
episodes in the Talara Basin before major sediment provenance shifted north into the
Tumbes Basin, possibly due to sea level retreat and/or major uplift of the basin. The
Oligocene sequences have been completed eroded off in most of the Talara Basin.
Vitrinite reflectance data in the Eocene section, however, indicates a maturity degree
reached with this post-Eocene overburden.
Source rocks from formations of Early Tertiary age, i.e. Eocene and Paleocene, may
have contributed to the hydrocarbon accumulation in the Talara Basin from still
undrilled deep areas to the west where they may have both better organic contents and
best maturity conditions than in the known drilled portions of the basin. Presence of
Oleanane in oil samples is indicative of late Cretaceous and/or Tertiary source rocks.
Presence of other biomarkers may tend to identify a post-Eocene age for the source
rocks in the basin; however, the post-Eocene sequences could have hardly achieved
sufficient maturity to generate hydrocarbons in the Talara Basin.
Geochemical Analyses of other unknown potential source rocks in the area are in
progress. In a recent field trip Perupetro geologist Y. Calderon, a member of our team,
visited a 100+ meter-thick dark gray shale outcrop with source rock potential attributed
to the Talara Formation in the Mancora Town area (Figure 28 A). This area is some 30
Km to the south of the site modeled by offshore Pseudowell 1; this shale unit also
outcrops 20 Km to the east of the Mancora Town preserving its lithological character
(Figure 28 B). The geological reconnaissance work is described in Appendix 3 of this
report (Y. Calderon, 2005). Geochemical analysis of this unit is in progress by Mr. P.
Baby’s Perupetro-IRD Group (personal communication).
52
The potential source rocks in the Tumbes Basin are also recognized based on the
Geochemical studies from offshore
and onshore well cuttings and
outcrop samples of the Oligocene
and Miocene sequences. Most of
the analyses performed on these
samples indicate the presence of
good quality organic contents in
the Mancora, Heath, Zorritos and
Cardalitos Formations, but all with
poor maturity. They are indicative
of the presence of potential source
rocks capable of hydrocarbons
generation with better maturity
conditions, a situation that is
present in deeper portions of the
basin. It is not known the
contribution of the Eocene and
pre-Eocene sequences in the
petroleum system scenario in the
Tumbes Basin. These sequences
must be present in deeper intervals
as
recognized
in
seismic,
especially in the south portion of
the basin. No offshore wells have
drilled these deep sequences.
Figure 28. Gray shales of the Talara Shale offer good visual source rock character in the
Mancora area in two sites distanced some 20 Km. away.
7.1.2.2. Cretaceous
The Cretaceous Muerto and Redondo Formations are excellent candidates to have
sourced significant amounts of hydrocarbons. The Redondo Formation contains Type II
and Type II-III Kerogen with TOC values typically over 1 wt%. The Muerto Formation
also contains excellent organic contents mainly Type II and II-III Kerogen in the Talara
Basin and adjacent Lancones Basin with TOC values typically in the 1-4.5 wt% range,
Tmax: 445 to 460 ºC and Equivalent Ro between 1 to 1.35 %. It is known that these
formations are present in a great portion of the Talara Basin. It is established that Type
II Kerogen of Muerto Formation generates much greater quantities of oil than does the
Type II/III Kerogen of the other source rocks. As a general statement it can be said that
the abundant presence of the biomarker Oleanane points towards a late Cretaceous
and/or Tertiary age source rocks.
Some Geochemical analyses have been conducted on samples from Cretaceous age in
the south portion of the Talara Basin. In the offshore Paita Sub-Basin, samples from
undifferentiated Cretaceous in the Paita PHX-O well have TOC between 0.76 and 0.56
and corresponding Tmax between 427 and 423ºC. Wells Sandino 6020, Mirador 5975
and Lomitos 3835 located on the onshore Negritos High have numerous Geochemical
analyses. Well Sandino shows consistent analyses with average TOC of 0.5 wt%, Tmax
of 436ºC (max 446ºC) and Ro of 0.74 % (six Ro analyses) down to 7500 ft in a section
comprising Paleocene and Upper Cretaceous above the Redondo Formation. Three
53
samples from the Redondo Formation in this well have an average TOC of 0.54 wt%,
maximum Tmax of 444ºC and Ro of 0.90%. Fifteen samples from the Redondo
Formation in well 5975 have TOC average of 1.02 wt% and average Tmax of 437ºC.
The Muerto Formation in the Sandino well has TOC average of 2.27 wt%, Tmax of
445ºC and Ro of 0.95%; whereas in the Lomitos 3835 well averages for the TOC
analyses are 2.98 wt%, Tmax of 450ºC and Ro of 0.88%. The Lomitos well has an
average TOC of 2.98-wt% and Tmax of 450ºC in six samples and Ro of 0.88 in one
sample from the Muerto Formation. Further south in La Casita 1X well in the Bayovar
Bay.
7.1.2.3. Paleozoic
The Paleozoic sediments are widely distributed in subsurface and on the eastern borders
of the Talara and Tumbes Basins. The Paleozoic sequence is typically made of
metamorphic rocks and other rocks with less degree of metamorphism. The Amotape
Formation of Paleozoic ages, as well as the pre-Cretaceous formations of Mesozoic age
contain an unknown series of geological events, which have been grouped as to
represent one (or more than one) major burial episode on this report. Post mature Ro
wt% of over 3.0 is described in the Lomitos field in Paleozoic sediments. The
commercial production established in Laguna, Portachuelo and San Pedro fields comes
from mainly quartzite and argillite reservoirs sealed by shales of Cretaceous or Tertiary
age and very likely sourced by same distal source rocks as in the Talara Basin proper.
Thus, it defines a late-Cretaceous/Paleozoic petroleum system.
7.1.3. Talara Basin
7.1.3.1. Sample Analyses
Perupetro (1999) performed geochemical analyses on samples from 16 wells in the
Talara Basin in the following stratigraphic units.
? ? Salina-Negritos
Early Eocene
? ? Balcones
Late Paleocene
? ? Mesa
Early Paleocene
? ? Mal Paso
Maastrichtian-Paleocene
? ? Petacas
Late Maastrichtian
? ? Monte Grande
Early Maastrichtian
? ? Redondo
Campanian
? ? Sandino
Basal Campanian
? ? Tablones
Early Campanian
? ? Pananga-Muerto
Middle Albian
A distribution of TOC wt% of samples from the Talara Basin is presented on Figure 29
and Figure 30 for DGSI (Perupetro, 1999) and existing data, respectively. One major
conclusion drawn from available studies is the recognition of the Cretaceous sediments
as the most likely source rock that has generated the hydrocarbons in the Talara Basin.
Future studies and analyses should define biomarkers to establish a positive
hydrocarbons/source rock correlation.
54
Talara Basin
Pariñas
Gr. Salina
Paleozoico
Gr. Mal Paso
Monte Grande
Redondo
Tablones
Muerto
Pananga
35
31
30
Frequency
25
23
20
17
14
15
9
10
3
1 1
0
1
7
6
5
5
5
3
2
3
0
0
0
0 0
1
1 1
0 0
0
0 0 0 0 0
1
0
0
0 0 0 0 0 0 0 0 0
0
0-0.5
0.5-1
1-2
PERUPETRO S.A.
DGSI Data
más>
de 5
2-5
TOC (wt%)
Figure 29. Total Organic Carbon in the Talara Basin, DGSI Data.
Talara Basin
50
45
43
40
Frequency
35
30
26
25
21
20
20
15
13
14
12
10
10
5
3
2
00 00
5
4
0
0
9
9
7
6 6
4
1
00
1
1
22
0
3
1 11
Heath
Carpitas
Chira
Gr. Talara
Chacra
Clavel
Palegreda
Gr. Salina
Pre-Cretáceo
Gr. Mal Paso
Monte Grande
Redondo
Muerto
Cretáceo Indif.
Amotape
7
4
00 00
5
0 00
1
2
2
1
0 000000 0 00
1
1
0000000 0000 00
0
0-0.5
PERUPETRO S.A.
PREVIOUS REPORTS
0.5-1
1-2
2-5
TOC (w%)
más de 5
>
Figure 30. Total Organic Carbon in the Talara Basin, Previous Reports.
The Geochemical evaluation conducted by Perupetro S.A. was performed on rock
samples and some oils from all onshore and offshore coastal basins. In general, the first
stage of the study considered the determination of TOC on selected well and surface
samples (with a cut-off of TOC > 0.4-0.5 wt%) distributed along the whole stratigraphic
column for additional Geochemical studies. Analyses run on the selected samples were
Rock-Eval Pyrolysis, Kerogen, soxhlet extracts, Liquid and Gas Chromatography (LC
and GC), Isotope Analysis, Gas Chromatography-Mass Spectrometry (GC-MS) of
Saturate (Biomarkers) and Aromatic hydrocarbons. Same analyses were performed on
oil samples and additionally API, Sulphur contents and High Resolution
55
Chromatography on the C7 range were analyzed. A 1D Geochemical modeling was
performed on the Talara Basin. DGSI, INC, from Woodlands, Texas, USA performed
the analytical analyses and the final integration and interpretation were performed by
LCV in Argentine.
In the adjacent Lancones Basin, the Muerto Formation has been defined as the best
source rock for predominantly oil generation and secondary gas generation. TOC from 1
to 4.5 wt%, excellent RockEval character, Type II and II/III Kerogen, Tmax of 445 to
460 ºC, equivalent Ro is 1 to 1.35 % in the last stages of the oil window and beginning
of the gas generation window. Extract analysis shows them to correspond to saturate
hydrocarbons, deposited in a marine environment with algal with carbonaceous and
poor terrigeneous contribution. Presence of what appears to be the Oleanane biomarker
implies an Upper Cretaceous to Tertiary age creating same discussion and observations
discussed in samples from the Negritos Talara High. The Redondo Formation
constitutes a second Cretaceous source rock with TOC of 1 wt%, Type II/III Kerogen,
oil and gas generator with high thermal maturity corresponding to the last stage of the
oil window. Extract analyses also show consistent presence of the Oleanane biomarker
as in the Muerto Formation and with high saturate hydrocarbons content. The samples
also correspond to deposition in a marine environment with common terrigeneous
contribution. Well drilling and regional correlation have confirmed the extension of
these Cretaceous Muerto and Redondo formations to the onshore and offshore Talara
Basin.
Source rocks in the Muerto and Redondo Formations are rich enough to have generated
the commercial amounts of hydrocarbons already produced in the oil fields of the Talara
Basin in addition to a sizeable amount of undeveloped reserves and as of yet,
undiscovered reserves onshore and offshore.
Regional Geochemical studies were conducted by Repsol attempting to establish an oilsource correlation between the South Talara and Sechura Basins with its hydrocarbon
findings while exploring Block Z-29 in the Trujillo Basin. These studies included
Geochemical analyses on:
1) Selected cutting samples from wells SBX-1 (SBXA) and La Casita 55X in the
Bayovar Bay,
2) Oil samples from the Portachuelo and Lagunitos wells in the South Talara Basin
and
3) Extracted oils from water samples from 10 offshore oil seeps in the Trujillo
Basin (Repsol, 1996).
The study did not conclusively identify the source rocks that generated the oil seeps and
the crude oils. Fifteen cutting samples from Maastrichtian 1841-2210 m. (6040-7250
Ft.) in well SBX-1 (should be SBXA) are organic poor with a TOC less than 0.69 wt%
and considered to be non-source rocks with immature 0.47% Ro. Three samples from
the Cretaceous Monte Grande Formation with TOC greater than 0.5 wt% had very low
HI and high OI values and plot as Type IV Kerogen with no hydrocarbon generation
potential. Some of the samples show oxidized mixed organic matter. In La Casita 55X
well, Geochemical analyses were carried out in eighteen shale samples from Cretaceous
Redondo (4 samples), Cretaceous Monte Grande (5 samples), Paleocene Balcones (6
samples) and Eocene Salina (3 samples) Formations. TOC from the Cretaceous and
Paleocene formations range from 0.81 to 3.74 wt% with HI of 17-61 mgHC/gTOC that
56
plot in the Type III/IV Kerogen. Visual Kerogen analyses indicate presence of 85%
vitrinite with mainly non-fluorescent amorphous organic matter up to 35% and minor
amounts of liptinite and inertinite. Vitrinite reflectance shows the Cretaceous, Paleocene
and Eocene Formations in the early stages of the mature window with Ro from 0.71 to
0.55 %. Samples analyzed appear to have marginal potential to generate gas. Cretaceous
Muerto/Pananga Formation samples analyzed in the Muerto Creek indicate a mean Ro
of 0.51 % (Repsol, 1996). The complete analyses show consistently increasing Ro
single less valuable counts in a range between 0.65 to 1.23 % and one single value of
1.82 %. The Quebrada Muerto is located in the Pazul area (basin) where the Lancones
Basin joins the Talara Basin.
7.1.3.2. Hydrocarbon Analyses
Most recent oil analyses refer to onshore and offshore Talara Basin samples, since
hydrocarbon samples from the Tumbes Basin are not available. As discussed below
several authors have attempted to identify appropriate biomarkers to establish
correlation with the hydrocarbons produced.
Perupetro (1999) had six oil samples and two oil seep samples analyzed. One seep
sample is from the Tumbes Basin, the remaining samples from the Talara Basin.
Analyses show the oils lying on the saturate side (Figure 31).
Oil sample analyses show slight to moderate biodegradation, API from 29.5 to 40.7°,
rich in saturate hydrocarbons, low sulphur content, equivalent Ro of 0.75 to 0.80 %, mix
of marine and terrigeneous organic material deposited under marine conditions with
high carbonaceous, algal and less terrigeneous input. All oils have moderate to high
Oleanane biomarker contents given a very definitive oil-source rock correlation with
source rocks of late Cretaceous to Tertiary age.
OIL COMPOSITION
100%
NSO+RES+ASPH
PERUPETRO S.A.
DGSI Data
Cca.
TalaraBASIN
TALARA
50
SAT 100%
TUMBES
BASIN
Cca.
Progreso
50
50
ARO 100%
From
the
analyses
performed
on
the
Perupetro S.A. study there
is no clear or definitive
oil/source rock correlation.
This may imply that oils
were
generated
from
distant source rocks of
Tertiary or late Cretaceous
age that were not sampled
in the study. An alternate
conclusion could be the
acknowledgment of a late
Cretaceous age to the
Muerto Formation, instead
of its recognized Albian
age.
Figure 31. Oil composition in the Talara and Tumbes Basins based on LC.
57
Crude oils from the Portachuelo field (five samples from wells 4352, 4912, 5237, 5558
and 5942), from the Inca 5-1 well (Sechura Basin, 1 sample) and from the Lagunitos
well 6120 have a common organic source with similar thermal maturities (Repsol,
1996). Biomarker analyses and high concentrations of Oleanane suggest a source with
mixed organic algal-bacterial-terrigeneous facies of Tertiary age, likely different than
oils from offshore seeps in the Trujillo Basin interpreted as derived from source rocks
of mixed organic facies rich in marine algal organic matter possibly of late Cretaceous
age. Although these statements differentiate Trujillo and Talara oils, it is clearly
indicated a potential correlation with a late Cretaceous origin for the Talara oils, since
Oleanane biomarkers are also indicative of this age.
Geochemical analyses of three oil samples from the Talara Basin wells and one oil seep
from Lobos de Afuera Island further south were carried out by UPPPL (1993). The light
crude, low sulfur oil samples correlate to a single oil family genetically related to a
source rock with strikingly similar Kerogen composition. Differences between them in
API gravity and wax paraffin contents reflect post generation history of alterations
caused by slight to moderate biodegradation, water washing and weathering. The oil
samples are from the Eocene Pariñas Formation in well 3927 in the Llano Field, the
Eocene Salina-Mogollon Formation in well 7496 in the Mirador Field and the Paleozoic
Amotape Formation in well 5166 in the Portachuelo Field. Oil sample analyses show
API from 29.5 to 40.7°, rich in saturate hydrocarbons and low sulphur content.
Kerogen contains predominant Type II oil prone marine organic matter deposited under
anoxic conditions with terrestrial contribution. Source rocks were in the main phase of
oil generation with thermal maturities equivalents to Ro of 0.7 to 0.8-wt%. A scale can
be set up with increasing maturity from least maturity observed in the Llano well, more
maturity in the Pariñas and Portachuelo oils and most maturity in the Mirador well. A
major conclusion is that all three oil samples belong to one oil family with low sulfur
content and a well-defined Kerogen Type. Biomarker contents point to a shale source
rock with influence of carbonates, a marine deltaic slightly reducing environment
superimposed over a marine carbonate platform. This Cretaceous or Paleocene
carbonate platform would not be the effective source rocks. Similar basin character has
been reported in the Santa Elena Eocene Basin in Ecuador, the Niger Delta in Nigeria,
the Indonesian Mahakan delta and in the Angola Congo Delta. The light 36-38º API oils
are capable of long distance lateral or vertical migration, a migration supported by their
low resin and asphalthene contents. All oils have moderate to high Oleanane biomarker
contents given a very definitive oil-source rock correlation with source rocks of late
Cretaceous to Tertiary age.
7.1.3.3. Oil Families
Current data does not permit to group the different oils into major genetic oil families
produced and or tested in the Talara and Tumbes Basins. However, there appears to be a
consensus to group all Talara Basin oils into one single oil group possibly one family
generated from one single source rock. It is difficult to visualize this single source rock
to be present outside the proper Talara Basin, although an oil-source rock correlation
from Talara oils to Tumbes Basin source rocks is mentioned and recent Geochemical
analyses suggest a Tertiary age, possibly the Heath Formation, as source rocks for the
Talara oils.
58
7.1.3.4. Oil-Oil and Oil-Source Rock Correlations
Various authors have attempted to establish positive correlation to potential source
rocks of the giant oil accumulation in the Talara Basin and of the hydrocarbon
occurrences in the Tumbes Basin. These analyses and discussions are also described
with some detail above.
From the analyses performed on the Perupetro S.A. study there is no clear or definitive
oil/source rock correlation. The potential source rocks of Cretaceous to Tertiary age
analyzed have not identified them as source rocks to definitely establish a genetic link to
the oils analyzed. The biomarker Oleanane is present in all oils analyzed, however,
absence of complete similar analyses on most well and surface samples does not allow
establishing a definitive oil-source rock correlation. A sample from the Muerto
Formation in well Lomitos 3835 in the Talara Basin had a TOC of 3.78 w% Tmax from
pyrolysis of 442 ºC, Type II mature Kerogen. LC, GC, isotopes and biomarker analyses
on extracts confirm good oil mostly algal marine source rock presently in the oil
window with equivalent estimated 0.9-1.0 Ro. The sample shows a very likely Oleanane
peak suggesting a source rock/oil correlation with most of the analyzed oils. The
Muerto Formation then is the effective source rock in this part of the basin; however,
the Albian age of this unit does not correlate with the abundance of the peak identified
as Oleanane that suggests a younger age for the unit. Additional similar analyses are
still needed to identify biomarkers to confirm positively the regional oil/source rock
correlation established locally in the above well.
The Oleanane discussion suggests the existence of source rocks of late Cretaceous
and/or Tertiary age in distant kitchens implying distant migration routes. The oil
discovered in rocks of Paleozoic age in the San Pedro 1X well in the Bayovar Bay this
year testifies this case. This may imply that oils were generated from distant source
rocks of Tertiary or late Cretaceous age that were not sampled in the study. An alternate
conclusion could be the acknowledgment of a late Cretaceous age to the Muerto
Formation, instead of its recognized Albian age.
The Oleanane age creates a discussion between some of the authors of Geochemical
studies in the Talara and Tumbes Basins. Gonzáles and Alarcón (2002) attributes a late
Cretaceous age to the abundant presence of Oleanane, supported by “ high resolution
Biostratigraphy”, to define the main source rocks as the Redondo Formation. Fildani, et
al. (2005) correlates the abundance of this biomarker to only Tertiary age and it goes
even further to suggest a correlation to the Heath Formation as the main source rock.
More details of these studies are presented in other portions of this report. Mobil (1993)
correlates the abundance of this biomarker to a late Cretaceous to Tertiary age and the
high heavy isotope composition d13 C derived to mid-Oligocene to younger source
rocks.
There is also no agreement as to the indications of biomarkers to establish a correlation
to a source rock with carbonate contents. Fildani (2005) again rules out the carbonate
contents in the source rocks, whereas UPPPL (1993) finds correlation to a source rock
with carbonate contents. The potential source rocks with carbonate contents includes the
Muerto Formation of Albian age.
59
7.1.3.5. Migration and Remigration of Hydrocarbons
Modeling in the Lomitos Field and the distribution of the oil accumulations and
potential source rocks in the Talara Basin suggest that the hydrocarbons have followed a
local and a regional eastward migration pathway from kitchens in the western offshore
portions of the basin to the onshore/offshore Talara Negritos High. The regional
implication is that the kitchen areas extend offshore to unexplored areas in deeper water
depths than has historically been drilled. Short-range gas and oil migration from deep
adjacent depocenters or kitchens known onshore offshore (Lagunitos, Malacas and
Siches Grabens) to the north and south of the three major structural highs (TalaraNegritos, Lobitos and El Alto-Peña Negra Highs) is also implied.
The recent offshore San Pedro oil discovery announced by PetroTech in the South
Talara Basin gives a sound understanding of migration routes. Based on old tests in the
offshore Belco’s La Casita 55X well, the area is dry-gas prone in the Cretaceous and
Tertiary reservoirs and in the extension of this basin to the onshore Sechura Basin
where commercial dry-gas production has been established by Olympic in Block XIIIB. Dry-gas tests in Cretaceous and Tertiary reservoirs and dry-gas prone source rocks in
La Casita well also point to a different distant source rock for the San Pedro oil, a
source rock that has not been drilled in the area. The other Belco well in the Bayovar
Bay SBXA TD’d in the Cretaceous Redondo Formation and was short of drilling a
prominent Paleozoic structure some 2Km. to the south with a culmination at 2500 m.
subsea. Wells La Casita and SBXA were abandoned in 1975 and 1985, respectively.
Remigration is also acknowledged in the Talara Basin caused during extensional
faulting and also possibly due to gravity sliding. The tectonism that created the
extremely complex normal block faulting occurred after primary migration. Detailed
structural work in the basin defines numerous major blocks bounded by sealing normal
faults. These major blocks are additionally faulted into smaller blocks where faults are
not seals, a condition known for the common oil-water contact affecting all the smaller
blocks. Hydrocarbons remigrated within these minor blocks to establish this condition.
Adjacent blocks tend to have their own oil-water contacts at different depths. Repetition
of large scale wedges caused by gravity sliding is also common, especially on the
northern portion of the basin where the Echino Formation and adjacent formations are
repeated even three times in some wells. Original hydrocarbon entrapment suffered
remigration during this younger gravity phenomenon and it is seen that blocks in
shallower wedges have lost original reservoir pressures and very likely have also lost
hydrocarbons.
As stated on the PARSEP reports “HC remigration is not adequately addressed for the
Peruvian oil fields”. At this stage, it is very early in the exploration history of the
Tumbes Basin to address the issue of young or old hydrocarbon recharge or migration
patterns caused by remigration. It is a fact that with more than one petroleum system
and the several tectonic episodes affecting the basin the presence of mixed petroleum
systems cannot be ruled out.
7.1.3.6. Hydrocarbon Kitchens
The interpreted tectonic, geologic history, geohistory modeling, oil occurrences and
production data point towards the presence of more than one hydrocarbon kitchen, very
likely representing major separate kitchens for the Talara and Tumbes Basins and
60
possibly a commingled kitchen where the two basins join and share common geologic
events.
The hydrocarbon kitchen(s) is (are) interpreted to be more likely present along the
western deep and/or offshore portions of the whole Talara Basin or local depocenters
where source rocks with adequate organic contents have reached best maturity
conditions. Measured vitrinite maturities in the Cretaceous and Tertiary sections mostly
do not exceed the late maturity oil window. Source rocks of early Tertiary or Upper
Cretaceous age reached a late maturity stage and generated hydrocarbons from late
Eocene to early Oligocene time in the Talara Basin. Hydrocarbons were expelled to the
east into offshore/onshore traps possibly former anticlines? during Oligocene time
before major tectonics faulted the original traps into smaller blocks with sealing faults.
Younger age tectonics faulted larger individual blocks into even smaller blocks many of
which were downthrown keeping their original oil-water levels at deeper depths. It is
emphasized here the nature of the numerous major faulted blocks bounded by normal
faults with sealing capacity, all these faulted blocks remained in a virgin state with
sealed pressures. A scenario with post-Oligocene source rocks that sourced the
hydrocarbons accumulation in the Talara Basin was hard to visualize since 1) they could
have hardly reached the oil window stage for lack of appropriate burial depth and 2) a
long distance hydrocarbons migration from source rocks in the deep Tumbes Basin
must have encountered numerous sealing fault barriers.
Oil discovery in Block Z-2B announced recently by Petrotech contrasts with
Geochemical data and Basin Modeling in the Bayovar Bay, an area where the South
Talara Basin merges with the Sechura Basin. Integration of available data from La
Casita 55X and SBXA wells and the San Pedro discovery establishes a long
hydrocarbon migration route from pre-Tertiary source rocks possibly of Cretaceous age
in hydrocarbon kitchens very likely located to the westernmost portions of the Bayovar
Bay. This same condition is the rule in the proper Talara Basin to the north and other
Peruvian basins.
7.1.3.7. Hydrocarbon Occurrences and Petroleum Systems
The late Cretaceous to early Eocene stratigraphic section includes the most likely source
rock of the major petroleum system that accounts for the giant oil accumulation in the
onshore and offshore Talara Basin. There are questions that remain to be answered as
the correct identification of the main source rock and kitchens in the basin. This main
Talara Petroleum System extends from the South Talara Basin in the Bayovar Bay (with
the recent oil discovery in well San Pedro 1X) to the North Talara Basin possibly up to
the Piedra Redonda-Zorritos Horst area. This petroleum system includes secondary
and/or combined petroleum systems with multiple reservoirs present in the whole
Cretaceous and Eocene sandstones and in the Paleozoic metamorphic sediments. The
most prolific oil accumulations in the numerous oil fields are found in reservoirs of
Eocene age. This common source rock that generated the oil accumulated in the
Cretaceous-Eocene reservoirs is also responsible for feeding the petroleum system
defined with reservoirs in Paleozoic reservoirs. Three prolific oil accumulations of this
petroleum system are widely distributed in the Talara Basin from Laguna in the north,
Portachuelo in the south both sealed by Cretaceous shales and further to the south in the
recent San Pedro oil discovery.
61
The potential source rocks of possible Talara Shale age in the Mancora town area in the
north Talara Basin will be investigated with more detail. Presence of coarse-grained
sandstones and conglomerates within this shale unit are attributed to some still undated
deep-sea turbidite deposits. Under favorable conditions the Talara Shale may proved to
be a self-contained petroleum system in this portion of the basin. In the Talara Basin to
the south, the Talara Shale unit is brown colored and it includes some turbidite units
with good reservoir character, as the Helico Member in the Carrizo Field. However,
most of the Eocene sequence lacks source rock potential onshore and in the shallow
offshore platform.
7.1.3.8. Reservoirs, Seals and Traps
The main oil and gas reservoirs are sandstones interbedded with shale seals in the
complete Eocene sequence. The Salina, Negritos, Lobitos and Lagunitos Groups consist
of fluvial, deltaic to nearshore marine sandstones. Main producing formations include
the Basal Salina, Mogollon, Pariñas Formation, Cabo Blanco and Echinocyamus
Formations of Early Eocene age. The Middle and Late Eocene Talara Group include
sandstone reservoirs in the Terebratula, Helico, Talara and Verdun Formations.
Few fields (Laguna, Portachuelo among others) produce oil and gas from fractured
quartzites of the Amotape Formation. Cretaceous production is found in four fields in
sandstones and conglomerates of the Redondo, Ancha and the Petacas Formations. Two
fields produce from shallow-marine sandstones of the Mesa and Balcones Formations of
Paleocene age.
It should be noted that slight oil shows were recorded in untested Paleozoic intervals in
the offshore Chira sub-basin bordering the Paita High in the South Talara Basin. The
short Paleozoic interval drilled between 1965 and 2040 ft in well PHX A consists of
70% gray sandstone and quartzite, with fine to medium grains: 20% white sandstone,
occasional green gray, medium to coarse grains, 10% metamorphic rocks. This section
had traces of fluorescence bright yellow. The RCX3-15X well had occasional oil shows
in cuttings from the Amotape with some fast streaming fluorescence and cut.
Primary seals are interbedded and overlying marine shales. Hydrocarbons fields are
normally found as numerous block-faulted traps caused mainly by extensional structural
normal faulting in the onshore and offshore Talara Basin. Other faulting includes lowangle gravitational slide faults and large vertical transcurrent faults.
7.1.4. Tumbes Basin
7.1.4.1. Sample Analyses
Geochemical analyses were performed on surface samples from the following units in
the Tumbes Basin (Perupetro, 1999).
? ? Cardalitos
Middle Miocene
? ? Mancora
Late Oligocene-Early Miocene
? ? Heath
Early Miocene
Outcrops samples from some levels of the Heath Formation are the only rocks found
with good potential hydrocarbons generative capability under more mature conditions.
These samples have TOC of 2.61 and 1.78 wt% with good S2 pyrolysis peaks,
immature Tmax 415 and 412 ºC derived from pyrolysis, amorphous organic material
62
with fluorescence deposited in anoxic marine conditions with terrigeneous contribution
based on chromatography of extracts.
Organic rich sediments are more common in the Heath, Zorritos and Cardalitos
Formations with good to excellent hydrocarbon generation attributes from Type II and
III Kerogen and subordinated Type I. Perez Companc S.A. (2000) conducted some
detailed investigations in 22, out of 72 cutting samples from offshore wells in an
Argentinean laboratory. Their results are summarized in Table 1.
Table 1. Geochemical analyses in the Tumbes Basin.
TOC (wt%)
Range Avg.
FM.
Kerogen
Comments
Corvina wells: Beginning early
generation window
Albacora and Delfin wells: good
Zorritos 0.78-3.45 2.00 Type I, II and I to very good generation
potential. Low maturity
Cardalitos 0.84-2.55 2.36
Delfin and Barracuda wells
Heath
1.31-1.93 1.72
Oil $ Gas
TUMBES BASIN
7
Cardalitos
Heath
Mancora
6
6
Frequency
5
4
3
2
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0-0.5
PERUPETRO S.A.
DGSI Data
0.5-1
1-2
2-5
más>
de 5
TOC (wt%)
Figure 32. Total Organic Carbon in the Tumbes Basin, data from DGSI.
Rock-Eval indicates predominant Kerogen Type III to III/IV with poor to fair potential
for gas generation in the offshore Tumbes Basin (Perez Companc, 2000). Exceptions
were found in wells Delfin 39X-1 in the Cardalitos Fm. interval 1372-1463 m. (45004800 Ft) and in the Zorritos Fm. interval 1774-1856 m. (5820-6090 Ft.) with mixed
potential to generate oil and gas. Thermal maturity shows Tmax of less than 430º C.
The Barracuda 15X-1 well interval 2469-2569 m. (8100-8430Ft) in the Cardalitos
Formation shows predominant amorphous organic matter with fair golden brown
fluorescence, with marine and continental palinomorphs and apparent gas potential
based on Rock-Eval. Interval 4151-4179m. (13620-13710 Ft.) in the Zorritos Fm. is
more terrigeneous with abundant presence of higher plant remains. Well Corvina 4010X has also low/moderate potential for gas generation.
63
TUMBES BASIN
Plio-Pleist.
Plioceno
Cardalitos
Cardalitos-Zorritos
Zorritos
Heath
Heath-Mancora
Mancora
Chira
Verdún
Gr. Talara
Chacra
Palegreda
Gr. Salina
3
30
25
25
22
20
Frequency
20
14
15
9
9
10
5
4
5
1
2
1
2
3
2
11
00
0
5
5
4
3
1
2
0
4
11
2
1
2
0
2
0
0
1
0
1
2
00
22
0000
0
1
000000
0000
000000000
0
0-0.5
PERUPETRO S.A.
PREVIOUS REPORTS
0.5-1
1-2
2-5
más >
de 5
TOC (wt%)
Figure 33. Total Organic Carbon in the Tumbes Basin, data Perupetro Files.
Shallow formations in the offshore Tumbes Basin also show high organic content as in
well Albacora 8X-1 (Sunmark, 1978). TOC’s from 12 shale and clay samples from the
Pliocene La Cruz and from 14 samples from the upper Miocene Mal Pelo average 2.81
and 0.81 wt%, respectively. Although organically rich and with excellent oil potential
these formations were found thermally marginally immature for the generation and
migration of liquid hydrocarbons.
Previous analyses by Graña y Montero Petrolera S.A. and American International
Company also found TOC highest average of 2.78 wt% in Zorritos from samples in the
entire section of the Tumbes Basin.
Other older reports as in the onshore well RT-65 indicate that the dark fine-grained
shales of the Heath Formation from 3990 to 4320 m (13,090-14,180 Ft) may be source
for oil and associated gas. TOC varies from 1 to 2wt%. This same interval may be
considered a better source potential for oil and associated gas and/or gas alone in a
deeper portion of the basin (ESSO, 1967).
In summary, the Mancora and Heath Formations in the Tumbes Basin have potential to
generate hydrocarbons. Data analyses from these source rocks from the sampled sites of
both formations indicate that they are not mature enough. Hydrocarbons occurrences
and thermal maturity, however, suggests existence of adjacent effective source rocks in
kitchen areas with deep depocenters.
7.1.4.2. Hydrocarbon Analyses
The Tumbes Basin lacks gas analyses to determine its origin, generation and correlation
with potential source rocks. Previous reported analyses show gas composition with near
98% methane and 2% of ethane, propane and CO2 in the Piedra Redonda and Corvina
gas wells.
64
7.1.4.3. Oil Families
Current data does not permit to group the different oils into major genetic oil families
produced and or tested in the Talara and Tumbes Basins.
7.1.4.4. Migration and Remigration of Hydrocarbons
A more complex migration pattern is interpreted in the Tumbes Basin due the presence
of more complex petroleum systems to account for all the hydrocarbons in the basin.
Basin modeling emphasizes the presence of the hydrocarbons kitchens in the deepest
undrilled portions of the Tumbes Basin bordering to the southeast and south of the
Banco Peru. At depths of 4.5 sec. the three or four main potential source rocks have
generated oil and gas. Hydrocarbons migration then occurred from these kitchens into
the shallow offshore platform and to the onshore basin to the east and northeast where
drilling has proved the hydrocarbons presence. Lateral migration distances of less than
50 km from the main kitchen areas or even shorter distances from local kitchens
controlled by the complex fault systems is established. This HC migration pathway
takes into account the lack of maturity conditions observed in all potential organic reach
source rocks defined in the offshore and onshore well cuttings and outcrops.
Vertical migration from pre-Mancora sequences, possibly of Eocene age, is also an
additional source for some of the hydrocarbons tested in the offshore Tumbes Basin.
Well Delfin 39-1X drilled to a TD of 2500 m. encountered the Zorritos and Heath
Formations at 1550 and 2200 m., respectively, and tested pure oil from both formations
and gas in the Zorritos Formation. Similarly, some oil was also tested in addition to the
gas in Piedra Redonda. These two structures have potential to have received some of
their hydrocarbons through vertical migration pathways.
A recent paper defined the dry gas occurrence in the Amistad Gas Field in Ecuador just
across the Peru-Ecuador border and north of the Albacora Oil Field as being biogenic in
origin (Deckelman, et.al., 2005).
As stated on the PARSEP reports “HC remigration is not adequately addressed for the
Peruvian oil fields”. At this stage, it is very early in the exploration history of the
Tumbes Basin to address the issue of young or old hydrocarbon recharge or migration
patterns caused by remigration. It is a fact that with more than one petroleum system
and the several tectonic episodes affecting the basin the presence of mixed petroleum
systems cannot be ruled out.
7.1.4.5. Hydrocarbon Kitchens
The interpreted tectonic, geologic history, geohistory modeling, oil occurrences and
production data point towards the presence of more than one hydrocarbon kitchen, very
likely representing major separate kitchens for the Talara and Tumbes Basins and
possibly a commingled kitchen where the two basins join and share common geologic
events.
A more complex scenario is present for the hydrocarbon kitchens in the offshore
Tumbes Basin. Source rocks and reservoirs are present in most of the stratigraphic
column in the onshore and the shallow offshore wells drilled in the Tumbes Basin. Oil
and gas were produced and tested in the Zorritos Formation in the Albacora field, pure
oil was also produced and tested in the Heath and Zorritos Formations in the Delfin
well, oil was tested in the Cardalitos Formation in the Barracuda well and pure gas was
65
produced in long duration tests in the Mancora and Zorritos Formations in the Piedra
Redonda and Corvina fields, respectively. However, all these known hydrocarbon
occurrences are present where potential source rocks from Eocene to Miocene age lack
adequate maturity conditions to have generated hydrocarbons. Basin modeling points
towards the presence of best maturity conditions in these various source rocks in deeper
portions of the basin bordering the eastern and southern limits of the Banco Peru. A
recent paper presented in INGEPET 2005 described the commercial dry-gas
accumulation in the Amistad Field in the Progreso Basin north of the Albacora Field in
Ecuador (Deckelman, J., 2005).
7.1.4.6. Hydrocarbon Occurrences and Petroleum Systems
Hydrocarbon occurrences and maturity values for the different source rocks analyzed in
the Oligocene to present stratigraphic section also define a second major complex postEocene petroleum system in the offshore Tumbes Basin. It is suspected that the Talara
Petroleum System also extends to some portions of the Tumbes Basin. Presence of oil in
reservoirs of the Zorritos Formation (Albacora field and Delfin well 39X), the Heath
Formation (Delfin well 39X) and gas and condensates in reservoirs of the Zorritos
Formation (Corvina field) and in the Mancora Formation (Piedra Redonda well 18X)
correlate to a petroleum system different than the one present in the Talara Basin
(Figure 1). The good source rocks identified in various post-Eocene formations point
towards a complex timing for the hydrocarbon generation, migration and trapping
mechanisms for the postulated post-Eocene petroleum system. However, absence of
reliable and consistent Geochemical analyses of oils and the unreliable identification
and definition of the pre-Oligocene stratigraphic sequences puts some questioning in the
definition of a unique petroleum system in this basin. Available reports indicate
unsuccessful attempts to locate oil samples for analyses from the Tumbes Basin to
establish oil to source rock correlations.
Figure 34. Hydrocarbon occurrences in wells in the offshore Tumbes Basin.
7.1.4.7. Reservoirs, Seals and Traps
Main reservoirs in the Tumbes Basin are included in the Oligocene and Miocene
Mancora, Zorritos and Tumbes Formations. All these formations have considerable
66
thick sequences of coarse clastics at various levels, even though they exhibit great
thickness variations.
Sandstones of the Mancora Formation with porosity of near 13% have been drilled
onshore and offshore in the basin. Over 1000 m. of this formation thins offshore with
potential to develop seafloor fans and/or turbidite deposits. Production tests in the
offshore Piedra Redonda structure were between 2.2 to 6.8 MMCFD, with estimated
Open Flow Rate of 21 MMCFD. Gas analysis yield 95% methane.
Following in the stratigraphic succession are conglomerates and quartzose sandstones of
the Zorritos Formation. It is considered the main reservoir in the basin based on
petrophysical character and measured permeability as observed in Table 2. Common
porosity between 16% and 25% and permeability up to 172 Md are measured and
interpreted in the offshore wells. Drilled thickness varies between 700 m. in Corvina to
1700m. in Barracuda. Well Corvina 40-15X tested 16 MMCFG from an interval at
1900m. with 23% porosity.
Table 2. Porosity and Permeability of Zorritos Formation in the Tumbes Basin.
POROSITY
PERMEABILITY
SWC
LOGS
(Md)
WELLS
Oil was produced and tested
from Zorritos reservoirs as
shown in Table 3. Oil
7.9
production was established
15.7
from the Albacora field with
production rates varying from
22.9
120 to 5250 BOPD from
various intervals at depths 3,600 to 4,500 m. The field cumulative production was
nearly 100 MBO in its short production history. The Delfin 39-5X well tested 269
BOPD of 37º API.
Albacora 8-X-2
Albacora 8-X-3
Barracuda 15-X-1
Delfin 39-5X
Delfin 39-11X
Corvina CX-12
Corvina 40-15-X
25.00
24.75
18.46
24.50
11.08
25.90
18.3
40
72
6.9
51.2
1.17
172
Table 3. Production tests in offshore wells in the Tumbes Basin.
Some reservoirs of Eocene
age may extend in the border
WET
with the Talara Basin in the
37 BPD 50% OIL 37 °API
southern portion of the
1,440 BOPD
basin, where seismic data
TIGHT
269 BOPD 36 API
indicates
presence
of
16.6 MMCFD (5/8"")
sediments of Eocene age.
8 MMCFD (1/2")
Some
indications
of
hydrocarbons were found in sandstones with porosity up to 13% in the Chira Formation
in the Piedra Redonda structure.
FM
TUMBES
CARDALITOS
ZORRITOS
ZORRITOS
ZORRITOS
ZORRITOS
MANCORA
WELL
Albacora 8-X-2
Barracuda 15-X-1
Albacora 8-X-2
Barracuda 15-X-1
Delfín 39-5-X
Corvina 40-15-X
Piedra Redonda C18-X
TESTS
7.1.5. Temperature Gradient
A Temperature Gradient Map was prepared in the Talara and Tumbes Basins using
digital data from selected wells (Figure 35). In general, the Talara Basin has higher
temperature gradient than the Tumbes Basin. The temperature gradient increases from
offshore to the onshore areas as expected. Highest temperature gradient is present in the
Talara Negritos High.
67
560000
520000
480000
ALBACO 8CD
ALBACO 12CD
ALBACO 9CD
ALBACO 7CD
1.14 0.89
1.23
ALBACO 8 3C
1.13 1.17
BARR 15 4X
1.55
ZORRITOS RT65
CX12 16X
CORV 41 6X
1.66
1.35
1.27
1.03
LA CRUZ Z5215
LA CRUZ Z5205
1.26
1.55 1.73
DELF B 5X
DELF B 11CD
9600000
ZORRITOS 5200
1.29
CORV CX13 18X
1.36
CORV 40 10X
9600000
1.44
CORRAL EPRCX1
1.35
RT59
ZORRITOS RT48
1.87
2.05
RT50
2.20
RX67
1.84
PIEDRA RED 14X
PIEDRA RED 13X
1.74
1.17
TRIGAL TRX1
0.79
PLATER PL X2
1.37
PLATER PL X3
9560000
9560000
CARPITAS C115
2.23
BARRANCO BAX1
CAPILLA CX 2
TX 35
1.42
1.85
1.33
1875
1.68
1.87 1.44 1.10 1.53
2.06
1.53
1725
6035
6060
1940
131
CARRIZO 1980
LO1 9X
LO3 22X
5505
4690
2.51 1.43
5340
1.36 T14 1
1.64
1.30 1.35
1.25
2.46
9520000
OLLOCOS OX- 2
1855 AX25
MISC SAL 5135
1.20
1.24
1.64
H5S X10
A3 22X
1.07 1.67
LO6 13X
1.84
1.41
ATASCADERO 1X
1.19
1.49
1.48
5380
5655
1.30
5080
LO5 13X
T 17
1.53 1.67
1910
1.80
0.55
9520000
5630
2010
1.85
XX 11X
PN1 12X
1540
5665 5680
1.18
AA 18X
LL 115 0.99 1.89 1.32
PN8 17X
1860 1865 1.57
1545
1.52 1.34
1.46
DD 12X 1.62 1570 1740
PN3 11X PN2 8X
5668 1.741.40
SICH 61X
1.34
CEREZAL CEX1
CAPILLA CX 1
2239
1555
ORXA 13X
CC X15
1.53
FONDO 4800
H7 X3
1.07
LO10-7X
LO10 20A
1.28 A1 6X
A1 5X
1.11 A1
8X
1.51
1.70
H9A X1
0.78 0.91
1.55 1.74
4875
ALV OVE 4835
1.66
ALV OVE 3885
1.22
2.26
MLX9 15X
1.08
8A X1
0.64
7B X1 1.59
1.46 PV15 10
7B X2
1.63
PVX13 6
1.08 6B X1 PVX8
13X
A4 19X
1.45 1.461.57 1.99
1.53
P26B X1
4120
2.64
4000
3835
1.67
1.64
4015
2.13
2.81
NHX1 7X
NHX1 19X
1.25
NHX 6
9480000
0.67 NHX 4 1.32
0.61 NHX 2B 3 X4 EE X3
0.78 1.54 LT8 11X
NHX 7
A5 9X
NHX 5
1.84 1.57
0.54 1.28
EX6 6X
EX6 2X
1.77EX6 8X
1.79
9480000
5325
1.49
5565
1.72
EX4 15X
1.52
NPXB-24X
1.25
10
0
10
9440000
20
30 km
9440000
CASITA 55X
1.53
9400000
SBX A
9400000
560000
520000
480000
1.54
Figure 35. Temperature gradient in the Talara and Tumbes basins
7.1.6. Geochemical Analysis. Sea Bottom Microbial Geochemical Analysis
Petrotech in Block Z-2B conducted Sea Bottom Microbial Geochemical Analysis.
Information gathered by this method was rated as successful as it confirmed
prospectivity previously detected in the area by seismic and Airmagnetometry and Air
gravity studies. Two hundred and seven samples (out of 311 attempts) were recovered
in a program run in the offshore Paita High area in the southern half of Block Z-2B in
1999. Samples consisted of 3-6’ taken at distances between 1 and 2 km. in water depths
of 50 to 500’.
69
7.2. Thermal Maturity And HC Generation Modeling.
7.2.1. Introduction
The present study completed basin modeling in the onshore-offshore Talara and
offshore
Tumbes
Basins
using
interpretation of the regional geology
and limited geochemical analytical data
from geochemical reports. Basin
modeling was conducted using software
BasinMod 1D Version 7.81 from Platte
River Associates. Inc., Denver, USA
licensed to Perupetro S.A.
Basin modeling was conducted on four
wells in the Talara Basin and two wells
and a pseudowell in the offshore
Tumbes Basin. Modeling was aimed to
determine the regional geothermal
history in the basin and the timing of
hydrocarbon migration. Burial history
diagrams, maturity versus depth
and/or time charts are presented for
modeled wells.
The four wells in the Talara Basin
include two onshore wells in the
Talara-Negritos High (Lomitos 3585
and Lomitos 3835 wells) and two
offshore wells in the South Talara
Basin (La Casita 55X well) where it
merges with the Sechura Basin (Figure
36). The Corvina 40X and Barracuda
15-4X wells and Pseudowell 1 were
modeled in the Tumbes Basin.
Figure 36. Basin Modeling in the Talara (La Casita 55X. Lomitos 3585 & 3835 wells) and
Tumbes Basins (Barracuda 154X, Corvina 40X & Pseudowell 1).
7.2.2. Data Input and Modeling
Data input for modeling were collected from studies filed in the Perupetro Technical
Archive and dated mainly from the 90’s, as those mentioned above. The status of each
parameter used as data input in the modeling, arranged in tables for each well, is
discussed below.
Vitrinite Reflectance Ro wt% data is still scarce and more analyses and data estimates
are needed to refine basin modeling in both basins. Selected wells in the Talara Basin
had a good collection of vitrinite reflectance data which was used to fit maturity
models, whereas the Tumbes Basin wells had scarce vitrinite analysis. Ro
information and trends were used to fit thermal modeling where available. Consistent
Ro data in the Paleozoic and in the Cretaceous to Tertiary intervals were found in very
few wells in northwestern Peru. Among them are in three Talara Basin wells used for
modeling, whereas all the offshore Tumbes Basin wells had insufficient Ro data. Early
Mature to Main Gas Generation Window characterize the Cretaceous and post70
Cretaceous sequences, whereas High post-mature values of Ro characterize the
Paleozoic metamorphosed sediments in the Lomitos oil field in the Talara Basin. This
same high Ro character in Paleozoic sediments is projected to Paleozoic sections in all
other Talara Basin localities, since Paleozoic sediments exhibit similar degree of
metamorphism where present. Metamorphosed Paleozoic sediments were drilled in
subsurface, as in Laguna and Portachuelo fields located on both north and south basin
extreme locations and it outcrops in the Amotape Mountains. A Paleozoic section is
suspected to be present in the core of the Banco Peru High in the Tumbes Basin.
Cretaceous and lower Tertiary (mainly Eocene) Formations and their geological events
are recognized and defined from detailed stratigraphic and biostratigraphic studies
produced during intense development and exploration of the numerous oil fields mainly
in the last 50 years in the Talara Basin. Additionally, extensive field geological work
and onshore/offshore drilling also have provided valuable biostratigraphic data to date
the post-Eocene thick stratigraphic column in the Tumbes Basin. The pre-Oligocene
sequences are not well recognized in the offshore Tumbes Basin. Although a clear break
should be present between Eocene and Oligocene, there is not enough data to determine
clearly the Eocene, Cretaceous and Paleozoic stratigraphic units that form the core
within shallow structural highs or the deep depocenters below the Mancora Formation.
Erosion depths of the different formations in the whole sedimentary section are good
estimates to better-fit regional thickness and sedimentation and erosion rates.
Table 4. Heat Flow in the Talara and Tumbes Basins.
Talara Basin
Time Heat Flow
(my) (mW/m²)
24
30-40
28
35-48
51
30-40
52
35-48
57
30-45
90
30-40
150
50-60
240
90
280
60-70
Tumbes Basin
Time
Heat Flow
(my)
(mW/m²)
3
40-28
9.5
25-20
10
40-25
14
28-25
15
40-28
30
30-20
57
40
90
50
The
Present
Day
Surface
Temperature used for the
modeling varies from 20 to 22º C
in the Talara Basin and a
consistent 22º C is used in the
Tumbes Basin. Heat Flow used in
the modeling varies considerably
in various portions of both basins.
Present Day Heat Flow ranges
from 32 to 37 and from 32 to 39
mW/m² in the Talara and Tumbes
Basins, respectively. Table 4
presents the estimated historical
Heat Flow used for modeling in
both basins. These estimated values lie consistently within ranges assumed for the
various geological episodes that characterized the basins in its geological development.
Areas to the south in the Bayovar Bay have a thin sedimentary section of Tertiary age
onlapping the local Basement made of intrusive and/or Paleozoic sediments. This
sedimentary cover thickens considerably westward and northward as additional Tertiary
and Cretaceous sediments onlaps the Paleozoic Basement, which in turn overlies what
has been interpreted as a deep Crystalline Basement. See both Basements on interpreted
seismic line RIB 93-08 in the Lobitos area on Enclosure 3h. Kerogen composition or
Kerogen kinetics are not used in the modeling.
Modeling results in the offshore portion of the Tumbes Basin completes the definition
of three main burial histories to account for the known hydrocarbon accumulations and
71
occurrences in the North western coastal basins in Peru. The oldest burial history of preCretaceous age is recognised in the Talara Basin where it is masked by metamorphism
of the Paleozoic sequences and by the unknown both geological history and of the
complete stratigraphic column and geological events of lower Mesozoic and Paleozoic
ages. Post-maturation of the pre-Cretaceous section accounts for the high vitrinite
reflectance Ro ranging from 3.8 to 5.0 wt% found in Paleozoic sediments in the onshore
South Talara Basin. Paleozoic sediments are known to present different degrees of
metamorphism in north western Peru. No hydrocarbons of Paleozoic age are recognized
nor interpreted to be present in the study area of the Talara and Tumbes Basins. A
second major burial episode is reflected in the existing Cretaceous to Eocene sequences
in the Talara Basin.
7.2.3. Talara Basin
The burial modeling performed in the Talara Basin outlines the regional maturity
conditions of the source rock sequences of Paleozoic, Mesozoic and Cenozoic ages.
Lack of sufficient data does not allow preparing of regional maps of the modeled
maturities in the Basin. Most of the stratigraphic section in the Talara Basin was
subjected to continuous burial and subsequent maturation during Cretaceous to
Oligocene time. This maturation history is superimposed on an old pre-Cretaceous
maturation burial of a thick Paleozoic section and an unknown Lower Mesozoic section
regionally identified underlying the Cenozoic section of the Basin.
Table 5. Well Sandino 6020 in the Talara Basin.
Well Sandino 6020
FM.
TOP M. Ro%
Gr. Mal Paso
151
0.74
Gr. Mal Paso
167
0.75
Gr. Mal Paso
1036
0.62
Gr. Mal Paso
1311
0.71
1692
0.74
Gr. Mal Paso
Gr. Mal Paso
1783
0.74
1859
0.80
Monte Grande
Monte Grande
2073
0.80
2286
0.89
Redondo
Redondo
2362
0.90
2545
0.90
Redondo
Muerto
2609
0.93
Muerto
2621
0.97
Muerto
2637
0.96
TD
2763
Modeling was performed in four wells including
the onshore Lomitos 3585 and Lomitos 3835
wells located on the Talara Negritos High within
current Block VII and the offshore La Casita 55X
and SBX-A wells located on current Block Z2AB operated by SAPET and PetroTech,
respectively, all in the south Talara Basin. The
Lomitos wells are located on the onshore TalaraNegritos High, whereas offshore wildcats La
Casita 55X and SBX-A were drilled in the
Bayovar Bay in the South Talara Basin where it
merges with the Sechura Basin. These two wells
are located 25 Km north and 20 Km NW of well
San Pedro 1X, the recent 35° API oil discovery
by PetroTech.
Vitrinite reflectance data reveals the original
presence of an important post-Eocene overburden
to account for the extrapolated maturity values
encountered in the Talara Negritos High. In
addition to the Lomitos well, the Sandino 6020 well has similar Ro data to place the
Paleocene and Cretaceous sections within the oil window as shown in Table 5.
The San Pedro 1X oil discovery in Block Z-2B by PetroTech contrasts with
Geochemical results and Basin Modeling conducted in wells SBX-A and La Casita
72
55X. This discovery and burial modeling interpretation establish a long hydrocarbon
migration path in this part of the basin as in other Peruvian basins. Well SBXA found
dry gas (Methane) on top of both the Eocene Salina Formation and on the top of
Cretaceous Monte Grande Formation sealed by shales of the Talara and Mal Paso
(Balcones?) Formations respectively.
The La Casita 55X well with its dry-gas tests is more likely located in a hydrocarbon
kitchen related to the onshore Sechura Basin, where dry-gas accumulations were
discovered in the 50’s by IPC. This discovery was followed by additional dry-gas
discoveries in the exploration campaign in the 90’s by Olympic in current Block XIII-B,
where a commercial gas project is under development.
7.2.3.1. Well Lomitos 3585, Negritos Talara High
The Lomitos 3585 well was drilled to a total depth of 2595m. in the Amotape
Formation. The stratigraphic section penetrated and geological events are presented in
Table 6.
Table 6. Well Lomitos 3585 in the Talara Basin.
Current modeling in the
Lomitos 3585 well on the
FM OR EVENT NAME
Negritos Talara High adds
TABLAZO
additional value to the
EROSION8
HEATH/MANCORA ERODED
previous modeling performed
EROSION7
by Perupetro S.A (Perupetro,
C.HILL/MIRADOR/CHIRA/VERD
1999) in this well. The burial
EROSION6
TALARA SHALE ERODED
history Time Vs. Depth
TALARA SHALE
24
500
diagram on Figure 37 shows
EROSION5
CHACRA/PAR ERODED
two major burial episodes of
PALEGREDA/SALINA
524
223
pre-Cretaceous and postEROSION4
Cretaceous ages. The former
BALCONES ERODED
BALCONES
747
379
burial is less known, whereas
MESA
1126
252
a continuous deposition marks
EROSION3
the post-Cretaceous burial
PETACAS/ANCHA ERODED
PETACAS/ANCHA
1378
795
episode from late Cretaceous,
REDONDO
2173
281
Paleocene to early Eocene
EROSION2
MUERTO ERODED
time. An erosion event took
MUERTO/PANANGA
2454
114
place during middle Eocene
HIATUS
followed by thick deposition
EROSION1
AMOTAPE ERODED
until late Eocene and an
AMOTAPE
2568
300
erosive event in the late
Eocene to mid-Oligocene. The maturity data show most of the pre-Mesa section frozen
in the “oil window”. The Cretaceous source rocks entered the Early Mature Window
during Paleocene and the Mid and Late Mature Windows since late Eocene, where they
are at present time. Potential source rocks of early Tertiary age entered the Early Mature
Window since late Paleocene time, where they are also at present time. The Talara
Group reached the Early Mature Window. The Maturity vs. Depth diagram on Figure 38
supports this model, as seen by the agreement with the measured vitrinite reflectance in
the pre- and post Cretaceous burials. The calculated curve is a best fit with the measured
vitrinite reflectance data.
WELL LOMITOS 3585
EVENT BEGIN
TYPE AGE (my)
F
1.6
E
10
D
25
E
32
D
40
E
41
D
42
F
52
E
53
D
55
F
57
E
58
D
59
F
62
F
65
E
66.4
D
68
F
74
F
83
E
90
D
95
F
112
H
245
E
256
D
308
F
322.8
TOP THICKNESS
(m)
(m)
5
19
73
Figure 37. Pre- Cretaceous and post-Cretaceous Maturity burials in the Lomitos 3585 Well.
Figure 38. Post-Cretaceous Maturity burial in the Lomitos 3585 Well.
74
The Lagunitos Graben to the south of the Talara Negritos High is considered one of the
onshore kitchens for the Talara Basin. Basin modeling in this deep through must
consider preservation of a complete Eocene section in excess of 7,500 m. in addition to
the sediments of Paleocene and Cretaceous age. Presence of rich gas is known to occur
in the north and south borders of the graben.
Based on the Time Vs. Depth burial chart of Figure 38 the source rocks at well Lomitos
at the Negritos Talara High were already in the main phase of the oil window and were
generating and expulsing oil before uplift and major block faulting. This area acted as
an oil kitchen since the late Eocene and this stage was frozen after the uplift that
stripped off most of the post-Talara sediments.
Figure 39. Maturity Vs. Depth. 1D Modeling in the Negritos High in the Talara Basin.
75
7.2.3.2. Well Lomitos 3835, Negritos Talara High
The Lomitos 3835 well was drilled to a total depth of 2726m. in the Amotape
Formation. The stratigraphic section penetrated and geological events are presented in
Table 7.
Table 7. Well Lomitos 3835 in the Talara Basin.
WELL LOMITOS 3835
FM OR EVENT NAME
EROSION8
EROSION7
C.HILL/MIRADOR/CHIRA/VERD
EROSION6
TALARA SHALE ERODED
TALARA SHALE
EROSION5
CHACRA ERODED
CHACRA
PARINAS
PALEGREDA/SALINA
EROSION4
BALCONES ERODED
BALCONES
MESA
EROSION3
PETACAS/ANCHA
REDONDO
EROSION2
MUERTO ERODED
MUERTO/PANANGA
HIATUS
EROSION1
AMOTAPE ERODED
AMOTAPE
EVENT BEGIN
TYPE AGE (my)
E
10
D
25
E
32
D
40
E
44
D
50
F
52
E
53
D
53.5
F
54
F
55
F
57
E
58
D
59
F
62
F
65
E
66.4
D
68
F
74
F
83
E
90
D
95
F
112
H
245
E
256
D
308
F
322.8
TOP THICKNESS
(m)
(m)
5
75
80
203
488
123
285
272
760
1356
596
38
1394
2313
919
258
2571
127
2698
200
Modeling in the Lomitos
3835 well on the Negritos
Talara High confirms the
previous modeling performed
in well Lomitos 3585 shown
above. The main conclusion
is the interpretation of earlier
generation and migration as
expressed
in
previous
interpretations in the Talara
Basin.
The burial history Time Vs.
Depth diagram on Figure 40
shows
a
continuous
deposition
between
late
Cretaceous and early Eocene
time. An erosion event took
place during middle Eocene
followed by thick deposition
until late Eocene and an
erosive events in the late
Eocene, mid-Oligocene and
Pliocene times.
The maturity vs. time model shows most of the Muerto-Pananga and Redondo
Formations section frozen in the “oil window”, in the Late Mature Window since
Oligocene time, before uplift, where they are at present time Figure 41. The potential
source rocks in this Cretaceous interval entered the Early Mature Window during
Paleocene and the Mid Mature Windows since early Eocene. Potential source rocks of
early Tertiary age entered and remained in the Early Mature Window during Eocene
time and the Mid Mature Window since Oligocene time, where they are also at present
time. The younger formations reached only the Early Mature Window.
Based on this modeling, the source rocks at well Lomitos at the Negritos Talara High
were already in the main phases of the oil window and were generating and expulsing
oil before uplift. This area acted as an oil kitchen since Eocene time and this condition
was frozen after the uplift that stripped off most of the post-Talara sediments.
The Maturity vs. Depth diagram on Figure 42 supports this model, as seen by the
agreement with the measured vitrinite reflectance. The calculated curve is a best fit with
the measured vitrinite reflectance data that clearly shows the two main burial episodes
in the Talara Negritos High.
76
Figure 40. Post-Cretaceous Maturity burial in the Lomitos 3835 Well. The Upper Cretaceous
in the Late Mature Window, the early Eocene interval in the mid-mature oil window and
younger Formations in the early-mature oil window.
Age (my)
Figure 41. Maturity versus Time plot in the Barracuda Lomitos 3835 Well.
77
Figure 42. Maturity versus Depth plot in the Lomitos 3835 Well.
7.2.3.3. Well La Casita 55X, Bayovar Bay
La Casita 55X well was drilled in 1974-1975 to a total depth of 3356.5 m. in a Granite
Crystalline? Basement. The well drilled 6 m. of Paleozoic quartzites underlying the
Cretaceous section and 28 m. of Granite rocks below the quartzites at TD. The MuertoPananga Formations are absent possible due to non-deposition, although they are
interpreted to be present in the westernmost portion of the Bayovar Bay where they
should overly the Paleozoic sediments. The stratigraphic section penetrated and
geological events are presented in Table 8.
Burial History, Maturity Vs. Depth and Maturity versus Time plots are presented in
Figure 43, Figure 45, and Figure 46. Modelling in the Bayovar Bay includes a regional
post-mature pre-Cretaceous burial history, a condition found in the Paleozoic
metasediments. The modelling in La Casita well indicates that the bottom of the
Redondo Formation entered the mid mature generation window in late Neogene time
(last 5my) and the early-mature oil windows in late Paleogene time, in Oligocene time
36my.
The upper Cretaceous Formations, upper Redondo and Monte Grande remained in the
early-mature window during Oligocene and Miocene time; the Salina interval only
reached the early-mature window in the last 5my.
78
There is also a good correlation of the model with Ro wt% as shown in Figure 45. As in
other wells in this area, predominantly Kerogen III and III/IV were analysed in the
Cretaceous section. Any of the liquid hydrocarbons found in the area must have
migrated long distances and have been generated from source rocks with different
organic contents than those found in the well. The regional modeling in the Bayovar
Bay indicates that the major synclinal area where the La Casita well is located may
correspond to a dry gas kitchen that generated the dry gas tested in this well in the
Cretaceous a Tertiary sandstone reservoirs and in the onshore Sechura Basin in Verdun
(see location map in Figure 36).
Table 8. Well La Casita 55X, Bayovar Bay.
WELL LA CASITA 55X
FM. OR EVENT NAME
TYPE
BEGIN AGE TOP (m)
(my)
EROSION8
HEATH
EROSION7
CONEHILLMIRADOR ERODED
CHIRA
VERDUN
EROSION6
TALARA SHALE ERODED
TALARA SHALE
EROSION5
CHA-PARI-PG ERODED
SALINA
EROSION4
BALCONES/MESA ERODED
EROSION3
PETACAS
MONTEGRANDE K
REDONDO
HIATUS
EROSION1
AMOTAPE ERODED
E
D
F
E
D
F
F
E
D
F
E
D
F
E
D
E
D
F
F
F
H
E
D
5
12
20
33
36
39
40
41
42
52
53
55.5
57
58
65
66.4
67
68
74
83
245
256
308
AMOTAPE
GRANITE
TD
F
F
322.8
THICKNESS
(m)
116
384
500
1195
695
131
1326
265
1591
584
2175
2623
2993
448
370
329
3322
3328
3356.5
100
79
Figure 43 and Figure 44. Burial history in Well SBX-A shows the base of the Cretaceous
Formation in the Mid Mature Window stage of the oil window and the overlying section in
the early mature window.
80
Figure 45. Maturity Vs. Depth in Well La Casita 55X.
Figure 46. Maturity Vs. Time in Well La Casita 55X.
81
7.2.3.4. Well SBXA, Bayovar Bay
The well SBX-A was drilled in 1974-1975 to a total depth of 2242 m. in the Redondo
Formation. The stratigraphic section penetrated, the deep projected stratigraphic section
and events are presented in Table 9. The well is located 20 kilometers northwest of the
recent Petro-Tech oil discovery well San Pedro 1X.
Table 9. Well SBX-A Formations and Events.
WELL SBXA
FM OR EVENT NAME
EROSION8
HEATH
EROSION7
CONEHILLMIRADOR ERODED
CHIRA
VERDUN
EROSION6
TALARA SHALE ERODED
TALARA SHALE
EROSION5
CHA-PARI-PG ERODED
SALINA
EROSION4
BALCONES ERODED
BALCONES
MESA
EROSION3
MONTEGRANDE K
REDONDO
SANDINO
EROSION2
MUERTO ERODED
MUERTO/PANANGA
EVENT BEGIN
TYPE AGE (my)
E
5
D
12
F
20
E
33
D
36
F
39
F
40
E
41
D
42
F
52
E
53
D
55.5
F
57
E
58
D
59
F
62
F
65
E
66.4
D
68
F
74
F
78
F
83
E
90
D
95
F
112
TOP THICKNESS
(m)
(m)
87.2
312.8
400
743
343
166
909
450
1359
280
1639
1725
86
80
1805
2112
2242
307
130
29
2271
300
The burial history diagram
and Maturity versus Time
plots are presented in Figure
47 and Figure 48. This well
did not penetrate the bottom
of the Cretaceous section.
Regional interpretation shows
the presence of a thick
Cretaceous interval in the
westernmost portion of the
Bayovar Bay where the
Muerto/Pananga Formations
overly
the
Paleozoic
sediments. A pre-Cretaceous
burial history is interpreted
based on the regional presence
of the Paleozoic metamorphic
rocks where a post-mature
condition has been reached. A
good fit of vitrinite reflectance
Vs Depth supports current
modelling as observed on Figure 48.
Modelling in the well SBX-A indicates that the bottom of the undrilled Muerto/Pananga
Formations entered the early-mature oil window in late Neogene time (last 5my). The
bottom of the Redondo Formation reached only a projected Ro of 0.45 wt% during the
same time. All the other younger post-Cretaceous Formations are immature. As in other
wells in this area, predominantly Kerogen III and III/IV were found in the Cretaceous
section. Any of the hydrocarbons found in the area must have been generated from still
undrilled source rocks very likely located further to the west and they have migrated
long distances.
82
Figure 47. Burial history in Well SBX-A shows the base of the Muerto/Pananga formations
in the early stages of the oil window and the immature overlying section.
Figure 48. Maturity Vs Depth diagram in well SBX-A shows two major burial histories.
83
7.2.4. Tumbes Basin
Basin modeling has limitations in the offshore Tumbes Basin. The basin lacks of
adequate complete Geochemical analyses and of a reliable recognition of the mostly
undrilled pre-Oligocene stratigraphic column and its geological events. An important
thick sedimentary section of pre-Oligocene age is recognized in seismic in the Piedra
Redonda and Delfin structures and it is very likely that it is also present in the deep
Tumbes Basin adjacent to the Talara Basin. This pre-Oligocene section is interpreted in
this report as of possible Eocene and pre-Eocene age. For modeling purposes only an
Eocene interval has been incorporated in the general stratigraphic sequence. Basin
modeling was conducted on three sites, including two wells Barracuda and Corvina
wells and a Pseudowell located in the deep portion of the basin. Modeling is limited due
to availability of reliable Geochemical data, especially due to limited Geochemical
analyses of hydrocarbons and the current absence of hydrocarbon samples from wells
for additional analyses.
7.2.4.1. Barracuda 15-4X Well
The Barracuda 15-4X well was drilled in 1973 to a depth of 4392m. in the Heath
Formation. The stratigraphic section penetrated, interpreted deeper stratigraphy and
geological events are presented in Table 10.
Table 10. Well Barracuda 15-4X in the Tumbes Basin.
WELL BARRACUDA 15 4X
EVENT BEGIN
FM OR EVENT NAME
TYPE AGE (my)
EROSION12
E
1.6
LA CRUZ ERODED
D
3
LA CRUZ
F
5.3
MAL PELO
F
6.5
TUMBES
F
9.5
EROSION10
E
11.2
CARDALITOS ERODED
D
12
CARDALITOS
F
14
EROSION9
E
16
ZORRITOS ERODED
D
17
ZORRITOS
F
22
HEATH
F
27
MANCORA
F
30
EROSION8
E
33
EOCENE ERODED
D
40
LATE EOCENE
F
48
EARLY EOCENE
F
57
The burial history diagram
and Maturity versus Time
plot are presented in Figure
49
and Figure 50. The
128
562
Oligocene-Miocene
Heath
690
378
and Mancora Formations
1068
1118
and a postulated late
Eocene interval entered
2186
476
only the early oil window
in late Neogene time and
the
younger
Zorritos2662
1100
Cardalitos
Tumbes
3762
1000
4762
238
Formations are shown in a
very immature stage. An
older possible Eocene unit
5000
1000
may have entered the mid6000
700
mature oil window in
Pliocene time. Origin of the small oil presence in the Cardalitos Formation is attributed
to migration from unknown source rocks from deeper portions of the basin.
TOP THICKNESS
(m)
(m)
84
Figure 49. Maturity burial in the Barracuda 15-4X Well shows the possible early Eocene
interval in the mid-mature oil window and the late Eocene and the Mancora and Heath
Formations in the early-mature oil window.
Figure 50. Maturity versus Time plot in the Barracuda 15-4X Well.
85
7.2.4.2. Corvina 40X Well.
The Corvina 40X well was drilled in 1974 to a total depth of 3829m in the Mancora
Formation. The stratigraphic section penetrated by the well, the interpreted deeper
section in the structure and the geological events are presented in Table 11.
Table 11. Well Corvina 40X in the Tumbes Basin.
WELL CORVINA 40X
The burial history diagram and
Maturity versus Time plot are
EROSION12
presented in Figure 51 and Figure
LA CRUZ ERODED
52. The older possibly an early
LA CRUZ
140
369
MAL PELO
509
333
Eocene unit may have entered the
TUMBES
842
758
mid-mature oil window in Pliocene
EROSION10
time. The Oligocene Lower Heath
CARDALITOS ERODED
CARDALITOS
1600
596
and Mancora Formations and a
EROSION9
postulated late Eocene interval
ZORRITOS ERODED
entered only the early oil window in
ZORRITOS
2196
684
HEATH
2880
852
late Neogene time. The younger
MANCORA
3732
168
Zorritos, Cardalitos, and Tumbes
EROSION8
Formations are shown in a very
EOCENE ERODED
LATE EOCENE
3900
1000
immature stage. Origin of the gas
EARLY EOCENE
4900
700
present in the upper Zorritos
Formation in the other Corvina wells is attributed to migration from unknown deeper
source rocks in the structure or from source rocks in deeper portions of the basin.
FM OR EVENT NAME
EVENT BEGIN
TYPE AGE (my)
E
1.5
D
3.5
F
5.3
F
6.5
F
9.5
E
10
D
11
F
14
E
16
D
17
F
22
F
27
F
30
E
34
D
40
F
48
F
57
TOP THICKNESS
(m)
(m)
86
Figure 51. Maturity burial in the Corvina 40X Well shows the bottom possible early Eocene
interval in the mid-mature oil window and the late Eocene and the Mancora and Lower
Heath Formations in the early-mature oil window.
Figure 52. Maturity versus Time plot in the Corvina 40X Well.
87
7.2.4.3. Pseudowell 1
The Pseudowell 1 is located on the deep SW end of seismic line AIP 92-49. The
interpreted stratigraphic section in the Pseudowell and the corresponding geological
events are presented in Table 12. All the Zorritos Formation is absent and the Cardalitos
Formation overlies directly the Heath Formation.
Table 12. Pseudowell 1 in the Tumbes Basin.
PSEUDOWELL 1
The
burial
history
diagram and Maturity
FM OR EVENT NAME
versus Time plot are
EROSION12
presented in Figure 53 and
LA CRUZ ERODED
Figure 54. Maturation of
LA CRUZ
376
1024
the stratigraphic section
MAL PELO
1400
1723
between the Tumbes to
TUMBES
3123
1522
EROSION10
early Eocene formations
CARDALITOS ERODED
from Early, mid and late
CARDALITOS
4645
687
Mature Window to Main
EROSION9
Gas Generation Window
ZORRITOS ERODED
occurred during Neogene
HEATH
5332
2020
time. Present day maturity
MANCORA
7352
500
shows
the Eocene interval
EROSION8
and the lower Mancora
EOCENE ERODED
LATE EOCENE
7852
500
Formation in the Main
EARLY EOCENE
8352
500
Gas Generation Window,
the upper Mancora and lower Heath Formations in the Late Mature Window, the upper
Heath and lower Cardalitos Formations in the Mid Mature Window, the upper
Cardalitos and most of the Tumbes Formations in the Early Mature Window and all the
youngest formations with depths of 3,000m in the immature stage.
EVENT BEGIN
TYPE AGE (my)
E
0.5
D
1.5
F
5.3
F
8
F
10.4
E
12
D
14
F
16.6
E
19
D
23
F
28
F
30
E
32
D
37
F
48
F
57
TOP THICKNESS
(m)
(m)
A detailed account of modeling in Pseudowell 1 will be given attempting to understand
the geological history and timing of passage of potential source rocks from the various
maturation episodes in an area considered one of the potential kitchens of the basin. The
Eocene interval entered the Early Mature Window in early Miocene time, the Mid
Mature Window during the remaining of the Miocene time, the Late Mature Window in
early Pliocene time and it entered the Main Gas Generation Window since late Pliocene
time Figure 54. The Mancora and Heath Formations had a similar early burial history;
they were in the Early Mature Window during all Miocene time and entered the Late
and Mid Mature Windows during Pliocene time. The lower Mancora Formation entered
the Main Gas Generation Window during late Pleistocene, but the upper Mancora and
the lower Heath Formation remained in the Late Mature Window. The upper Heath
Formation stayed in the Mid Mature Window until present time. The Cardalitos
Formation entered the Early Mature Window in early Pliocene time and only the lower
portion of this formation entered the Mid Mature Window. The upper Cardalitos and
most of the Tumbes Formations remained in the Early Mature Window, whereas all the
remaining younger formations are immature.
88
Figure 53. Maturity burial in the Pseudowell 1 shows modeled stratigraphic units from
possible Eocene interval in the Main Gas Generation Window to immature units from the
upper Tumbes Formation to younger units.
Figure 54. Maturity versus Time plot in the Corvina 40X Well.
89
Modeling of Pseudowell 1 places the various potential source rocks in maturity
condition to have generated oil and gas on this particular location, a situation tested by
the hydrocarbons occurrences in the different offshore wells. Modeling places the Upper
Oligocene Lower Mancora Formation and the pre-Oligocene sequence, possibly
Eocene, in the Main Gas Generation Window since Pliocene time. The other two
potential source rocks Heath and Cardalitos Formations contributed to oil generation in
the basin and may be source for some of the tested oils. A portion of the pre-Oligocene
sequence may correlate with a Talara Shale unit that outcrops in the onshore Mancora
area with source rock potential as described above Figure 28.
Hydrocarbons charge contributed by deeper potential source rocks is unknown in the
Tumbes Basin.
90
8.0. PROSPECTS AND LEADS IN THE TALARA AND TUMBES FOREARC
BASINS
that remain as untested prospects and leads to target extensive stratigraphic columns. In
the course of this study six of them in the Talara Basin and thirteen in the Tumbes Basin
have been documented in Chapter 8 (Table 13). The areas adjacent to some of them also
offer additional exploration opportunities as indicated below. Although most areas in
these basins are under different exploration stages, there exist prospects and leads of
especial interest for future promotion as those defined in open areas or in areas under
PEA’s (Block Z-34) or under negotiations (Blocks Z-37 and Z-38) where license
contracts are not yet signed.
Oil discovery in the San Pedro 1X well renewed hydrocarbon exploration of the
Paleozoic rocks in the whole NW Peru. Prospects and leads and areas for additional
exploration of Paleozoic include the Calamar Lead and similar areas to the south, west
of the Bayovar Bay in areas interpreted as potential hydrocarbon kitchens (Block Z-37).
In the very shallow offshore open area west of the Paita High oil shows were found in
Paleozoic rocks but were not tested. All these areas are geologically related to the San
Pedro discovery and need additional seismic data to fully evaluate their hydrocarbon
potential. The Caballa and Tortugas are well-defined structures located near San Pedro
in Block Z-2B.
Similar geological conditions develop further to the north on the western border of the
shallow platform in the border of PEA’s Z-34 and Block Z-2B. This area is highly
attractive for exploration of pre-Eocene sequences of which the Paleozoic is also the
main target. These areas are the offshore western extension of the three main tectonic
highs of the Talara Basin. The Deeper Lobitos Lead is defined as an example of what
can be defined on this platform. The deep platform of the Talara Basin in Area Z-34
offers a sedimentary section attractive for deep-water exploration that needs extensive
additional seismic data. Scarce seismic defines the Tiburon Lead as a large structure.
The Mero, Merluza, Paiche, Atun and Banco Peru structures and partially the Lenguado
and Espada structures are located in Block Z-38 in the Tumbes Basin. The Jurel, Raya,
Perico, Toyo, Chita and Deeper Delfin structures include hydrocarbon prospectivity,
which had not been described as potential plays in Block Z-1.
The Zorritos-Piedra Redonda High or Lead is another attractive exploration site located
in the transition zone between the offshore Tumbes Basin and the onshore Talara and
Tumbes Basins. The ZPR Lead runs for 60 Km as a SW-NE trending horst bounded by
steeply dipping normal listric faults, that place the structure updip of both offshore and
onshore potential kitchens areas. This onshore kitchen also represents a kitchen area for
the onshore fields.
Previous studies defined other potential prospects and leads, but with a different
petroleum system as defined in the present study. This old prospects and leads are
described in Appendix 4. The attractiveness for hydrocarbon exploration of potential
Cenozoic and Paleozoic sections in the Banco Peru, for instance, had never been
recognized. This feature has poor seismic definition and it is larger than the Talara
91
Negritos High, which has cumulative production of over 600 MMBO, most of which
was produced with no seismic data.
8.1. New Prospects and Leads
that remain as untested prospects and leads related to:
i)
gravitational tectonics, which have created planar and curved rollover anticline
structures, some of which have developed a compression component affecting the
Tertiary, Cretaceous and Paleozoic sections,
ii)
a major subaereal unconformity SU that has generated important stratigraphic
traps. In the Neogene Tumbes Basin, this subaereal unconformity is represented at the
base of the Cardalitos Formation (Middle Miocene), while in the Paleogene Talara
Basin it is represented at the base of the Talara and Verdun Formations, and
iii)
the presence of reservoir quality sedimentary sequences that have been produced
in deep-water stratigraphic facies and turbidities channels. These deposits have a large
potential as hydrocarbon traps. The identification of the reservoir properties of these
potential traps requires high-resolution seismic data, extensive seismic reprocessing
and knowledge of the depositional characteristics and their architectural elements. In
the south Talara Basin, the interpreted seismic of turbidities facies in the Verdun
Formation shows up as amplitude anomalies. In the Tumbes Basin, the deep water and
turbidite reservoirs are present in the Cardalitos, Heath and Mancora Formations.
One of the most important exploration concepts when generating prospects in the
Tumbes and Talara Basins is related to a combination and interaction of stratigraphy
and tectonic (Table 13). In the Tumbes Basin, the major period of deformation occurred
in the Pliocene forming the main rollover structures. The prospects and leads within the
pre-Cardalitos section are thus a combination of subcrop edges and structure.
Table 13: List of Prospect and Leads in Tumbes Basin and South Talara Basins
1
2
3
4
5
6
7
8
9
10
11
12
13
PROSPECT AND LEADS
TUMBES BASIN
Atun
TALARA BASIN
Banco Peru Area
Chita Prospect
Deeper Delfin Lead
1 Calamar Lead
Espada Lead
2 Caballa Prospect
Jurel Lead
3 Tortuga Prospect
Lenguado Lead
4 Deeper Lobitos Paleozoic Lead
Merluza Lead
5 Mero Lead
Paiche Prospect
6 Tiburon Lead
Perico Lead
Raya Prospect
Toyo Prospect
Zorritos - Piedra Redonda High
92
Figure 55: Prospects and Leads in Tumbes and North Talara Basin
93
8.1.1. Tumbes Basin
8.1.1.1. Atun Prospect
The Atun structure is located 10 km SE of the Banco Peru structure. This structure
corresponds to an anticline associated to normal listric faulting with a deep pre-Mancora
detachment level (Figure 56, Figure 57, Figure 58). This structure is an elongate E-W
structure with two culminations, closure against normal faulting and with very clear
structural closure. The Atun structure is related to a gravitational tectonics occurred
during the Pliocene times.
The exploration target is the Zorritos Formation sealed by transgressive sequences of
the Cardalitos Formation. A second target corresponds to deep-water reservoirs in the
Heath Formation.
Dimensions:
??Length W-E: 5.5 km.
??Width N-S: 2.5 km.
Structural Highest point: East Culmination 2.570 ms., West Culmination: 2.580 ms.
Structural Closure: +/- 80 ms.
Well defined by seismic Lines: OXY98-114, OXY98-115a, OXY 98-226, OXY98-225,
and API92-12.
Figure 56: Two-way time structural map on the top Cardalitos Formation, showing the Atun
Prospect.
94
Figure 57: Seismic line OXY98-114 showing the east culmination of the Atun structure.
Figure 58: Seismic line OXY98-115a showing the west culmination of the Atun structure.
95
8.1.1.2. Banco Peru Prospective Area
The Banco Peru structure is located on the western edge of the offshore Tumbes Basin.
This structure has a prospective area of over 50 km in length and 20 km in width
partially found in 100 m water depth. The Banco Peru prospective area is defined as a
NE-SW horst structure, limited to the East by the “Banco Peru” normal Fault. This
structure could contain Cenozoic sediments overlying possible Paleozoic metamorphic
rocks. Within the structure itself other smaller structures can be identified that are also
associated to normal faults (Figure 59, Figure 60, Figure 61, Figure 62, Figure 63).
The main targets in the Banco Peru structure are Paleozoic and Cenozoic sequences.
This area needs additional seismic.
Approximate Dimensions of the area:
??
Length NE-SW: 25-30 km.
??
Width E-W: 8-10 km.
??
Structural Highest point: 0.600 ms.
Well defined by seismic Lines: 93-20, 93-01, 93-02, 93-00, OXY98-221, OXY98-216,
and OXY98-226.
Figure 59: Two-way time structural map on the top Zorritos Formation, showing the Banco
Peru Prospective area.
96
Figure 60: West to East seismic line Rib 93-01 across the Banco Peru Prospective area
Figure 61: Seismic line RIB 93-01 flattened on Zorritos Formation, showing the Banco Peru
structure and Tumbes basin
97
Figure 62: Seismic line RIB 93-02 across the Banco Peru structure
Figure 63: NW to SE seismic lines OXY 98-221 across the Banco Peru Structure.
98
8.1.1.3. Chita Prospect
The Chita Prospect is located 8 km south of the Barracuda 15X well. The Chita prospect
corresponds to a large rollover anticlinal structure dipping to the SE. This prospect is
possibly related to an ancient Eocene structure that was re-activated during the Neogene
times.
The Chita structure is a good example of a combination trap whose structural and
stratigraphic parameters interact, increasing its size potential (Figure 64). The
exploration targets are represented by the marine neritic to deltaic sequences of the
Tumbes and deep-water pre-Tumbes Formations sealed by the transgressive deposits of
the Mal Pelo and Cardalitos Formations (Figure 64). Deep potential targets of this
structure are within the deep-water reservoirs of Pre Mancora and/or Eocene series. In
the offshore area of the Tumbes Basin, these formations have hydrocarbon potential but
as of yet have not even been explored for and constitutes a new exploration target
(Figure 64).
Figure 64. Chita prospect defined by seismic line RIB 93-01, showing the principal
exploration targets. More details can be found in Appendix 3 and Enclosure 3p.
99
Dimensions (Figure 65, Figure 66, Figure 67)
?? Length N-S: 5.5 km.
?? Width E-W: 3.5 km.
?? Structural Highest point: 1.710 ms.
Structural Closure (Figure 65, Figure 66, Figure 67): +/- 160 ms.
Well defined by seismic Lines: AIP92-59, AIP92-29, PC99-09, PC99-06 and PC99-08.
Figure 65: Two-way time structural map on the top Zorritos Formation, showing the Chita
Prospect.
Figure 66: NW to SE seismic line PC 99-09 across the Chita Prospect
100
Figure 67: Seismic line AIP 92-29 showing the Chita Prospect and the Barracuda structure.
8.1.1.4. Corvina type lead associated to Chita Prospect
Stratigraphic leads were found on the western area of the Chita structure, associated
with Middle Miocene subaerial unconformity (SU, base of the Cardalitos Formation).
This play is a combined structural/stratigraphic trap similar in nature to the “Corvina”
play type.
The “Corvina type lead” structure is an elongate N-S structure mapped with two main
culminations and with structural four-way dip structural closure (Figure 68, Figure 69,
Figure 70).
Dimensions (Figure 68, Figure 69, Figure 70)
?? Length N-S: 5.5 km.
?? Width E-W: 2.5 km.
Structural Closure (Figure 68, Figure 69, Figure 70): +/- 150 ms.
Well defined by seismic Lines: AIP92-10, AIP92-11, AIP92-09, PC99-28, PC99-30 and
PC99-26, and OXY98-221.
101
Figure 68: Structural 2WT on the top Zorritos Formation map, showing the Chita
stratigraphic prospect.
Figure 69: Composite seismic profile A-A1, showing the Chita stratigraphic lead.
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Figure 70: Isopach map of the Corvine Type lead on Zorritos Formation associated to Chita
Prospect
8.1.1.5. Deeper Delfin Lead
This structure is a new lead identified in the Tumbes Basin. The Deeper Delfin Lead is
associated with the Delfin structure, which is an ancient feature that was possibly a
rollover structure during Eocene time (Figure 71). Nowadays the Delfin feature
corresponds to a horst structure. The Delfin 39-X-1 well was drilled on the top of this
shallow Delfin structure and reached the top of Heath Formation at 2200 m. and tested a
total of 330 BOPD of 37º API in both the Zorritos and Heath Formations.
Seismic reveals the presence of an attractive thick sedimentary interval that remains
untested below the Delfin wells TD at around 2 seconds TWT. The Deeper Delfin lead
has excellent structural geometry and timing for hydrocarbon generation and migration.
The deeper targets correspond to Pre-Mancora and are mainly Eocene age series. These
sequences could have hydrocarbon accumulations that were generated in different
stages of Eocene and Neogene time (Figure 71).
103
Figure 71: Deeper Delfín Lead defined by seismic line AIP 92-49, showing the potential
structural configuration and explorations targets. More detail can be found in Appendix 3
and Enclosure 3p.
8.1.1.6. Espada Lead
The Espada lead is located 16 Km SW from the Barracuda structure and it is defined by
seismic line AIP 92-66 (Figure 72, Figure 73). It corresponds to the largest rollover
anticline structure associated to listric normal faults, apparently with a main culmination
and with four-way dip closure. Its main culmination is approximately 600 ms higher
than Barracuda. This prominent lead needs new seismic for better definition
Dimensions
??Length N-S: 4.0 km.
??Width W-E: 3.0 km.
??Structural Highest point: 1.080 ms.
Structural Closure: +/- 250 – 280 ms.
Well defined by seismic Lines: OXY98-234a, OXY98-117, OXY98-116a, OXY98-235,
AIP92-65, and AIP92-18b.
104
Figure 72: Two-way time structural map on top Zorritos Formation showing the Espada
Lead.
Figure 73: NW to SE seismic lines AIP92-66 showing the Espada Lead.
105
8.1.1.7. Jurel Lead
The Jurel Lead is located 5 km East of the Perico structure. This lead has an excellent
structural geometry for hydrocarbon entrapment as defined by seismic line AIP 92-12
(Figure 74). The Jurel lead corresponds to combination trap with the Middle Miocene
subaerial unconformity and Pliocene gravitational tectonic.
The main exploration targets for this lead are the reservoirs of the Zorritos Formation,
sealed by sequences of the Cardalitos Formation. The secondary reservoir target is the
Tumbes Formation, sealed by Mal Pelo.
Figure 74: Jurel Lead defined by seismic line AIP 92-12, showing the potential structural
configuration and explorations targets
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8.1.1.8. Lenguado Lead
The Lenguado Lead is located 30 Km to the SW of well Delfin 39-X-1. This structure is
an old NW –SE trending rollover anticline associated with a listric normal fault defined
in seismic line AIP 92-49 (Figure 75). According to the seismic interpretation, the onset
of this structure probably began in Eocene time. The Mal Pelo and La Cruz formations
show minor syn-sedimentary deformation, implying low tectonic activity during Late
Miocene for this structure.
The Lenguado Lead has an excellent structural geometry and timing for hydrocarbon
generations. The Zorritos Formation is one of the principal reservoir targets in the
Tumbes Basin; however, it has been eroded in this area. The exploration targets for this
lead are the deep-water reservoirs of Mancora and Pre Mancora or Eocene Series and
possibly also in the Cardalitos and Tumbes Formations. These sequences are found at a
depth of 3.5 seconds TWT.
Figure 75 Lenguado Lead defined by seismic line AIP 92-49, showing the potential structural
configuration and explorations targets
107
8.1.1.9. Merluza Lead
The Merluza Lead is in south Tumbes Basin. This Lead is a planar rollover anticlinal
structure associated with the Piedra Redonda normal listric fault (Figure 76). This
structure has been cut by younger faults, which divide the structure into a number of
blocks.
The prospective targets for the Merluza lead are the Tumbes and Mancora reservoirs
and the Eocene series. The Zorritos Formation in this area has been eroded by the
Middle Miocene subaerial unconformity (base of Cardalitos Formation.
Figure 76. Merluza Lead defined by seismic line RIB 93-05, showing the potential structural
configuration and explorations targets. More detail can be found in Appendix 3 and
Enclosure 3p.
108
8.1.1.10. Paiche Prospect
The Paiche structure is located in the SW portion of the Tumbes basin. It corresponds to
an anticlinal structure associated to gravitational tectonics. The Paiche prospect is an
elongate West-East structure with a main culmination and with structural closure
against faulting (Figure 77, Figure 78).
Dimensions.
?? Length W-E: 8.5 km.
?? Width N-S: 4.5 km.
Well defined by seismic Lines: OXY98-113, OXY98-112ab, OXY98-111 and OXY98210, 93-4.
Figure 77: Two-way time structural map on the top Zorritos Formation, showing the Paiche
Prospect.
109
Figure 78: NW to SE seismic lines OXY 98-210 showing the Paiche Structure
8.1.1.11. Perico Lead
The Perico Lead is located 18 km west of the Piedra Redonda well. This lead is a
rollover anticline structure associated with normal faults (Figure 79). The Perico Lead
correspond of a combination stratigraphic and structural trap related to the preCardalitos unconformity and Pliocene gravitational tectonic.
The target with the highest potential is represented by the sequences of the Zorritos
Formation, which is sealed by the Cardalitos Formation. Additionally, the Perico lead
presents deeper exploration targets for reservoirs of the Mancora Formation and Eocene
sequences.
110
Figure 79. Perico Lead defined by seismic line AIP 92-12, showing the potential structural
Enclosure 3p.
8.1.1.12. Raya Prospect
The Raya prospect is a robust and elongate N-S structure with two main culminations
and with four-way dip structural closure (Figure 80). The structure is associated to the
Pliocene gravitational tectonic and subcrop beneath the Cardalitos unconformity
occurred in Miocene time (Figure 81, Figure 82). The Tumbes Formation sealed by the
Mal Pelo Formation represents the potential reservoir horizons.
Dimensions
??Length N-S: 5.5 km.
??Width E-W: 2.5 km.
111
Well defined by seismic Lines: AIP92-10, AIP92-11, AIP92-09, PC99-28, PC99-30,
PC99-26, and OXY98-221.
Figure 80: Two-way time structural map on the top Cardalitos Formation, showing the Raya
Prospect
112
Figure 81: Seismic line AIP 92-32 across the Raya Structure
Figure 82: North to South seismic line AIP 92-10 showing the Raya Structure
8.1.1.13. Toyo Prospect
The Toyo prospect is a well-defined structure with one main culmination and closure
against faulting (Figure 83). This structure is associated to the gravitational tectonics of
Pliocene time and subcrop at the base of the Cardalitos Formation (Middle Miocene).
113
The Toyo prospect corresponds to a rollover anticline structure associated with listric
normal faults dipping to the NE (Figure 84, Figure 85).
The exploration targets are represented by the marine neritic to deltaic reservoirs of the
Tumbes Formation sealed by the Mal Pelo Formation. In this area, the Zorritos
Formation was eroded completely.
Dimensions
??Length W-E: 8 to 10 km.
??Width N-S: 3.5 to 4.5 km.
Structural Closure: +/- 500 to 600 ms.
Well defined by seismic Lines: AIP92-21, AIP92-22, AIP92-23, AIP92-24,
AIP92-41, PC99-12, PC99-14, PC99-16 and PC99-18.
Figure 83: Two-way time structural map on the top Cardalitos Formation, showing the Toyo
Prospect.
114
Figure 84: SW to NE seismic line PC 99-16 across the Toyo Structure.
Figure 85: Seismic line AIP 92-41 showing the Toyo Prospect.
115
8.1.1.14. Zorritos-Piedra Redonda Lead
This lead is located in the transition zone between the offshore Tumbes Basin and the
onshore Talara and Tumbes Basins (Figure 86). The ZPR Lead is a SW-NE trending
horst bounded on the SE and NW flanks by steeply dipping normal listric faults.
Internally, other structures can be seen associated with normal faults that set up several
other prospective leads.
The importance of the Zorritos-Piedra Redonda High is that it is a structure located
updip of both offshore and onshore potential kitchens areas (Figure 86). This onshore
kitchen also represents a kitchen area for the onshore fields. The seismic interpretation
shows the Zorritos-Piedra Redonda High deformed by an older set of faults involving
Eocene sequences.
Figure 86. Zorritos-Piedra Redonda Lead.
8.1.2. Talara Basin
The offshore Talara Basin is comprised of two Deep and Shallow platforms separated
by the Talara and a series of listric normal faults. All exploration and development have
been carried out only in the shallow platform. These platforms still have high potential
for additional hydrocarbon exploration. In general, all exploration in the Talara Basin
requires additional modern seismic and new structural and geological concepts.
The Petrotech oil discovery San Pedro 1X has open all the Bayobar Bay and
surrounding areas for exploration of Paleozoic metamorphic rocks. Untested Paleozoic
intervals exist in nearby areas with and without license contracts, as west and north of
La Casita well (Figure 88). Since Paleozoic production extends now from onshore
Laguna Field to the north to San Pedro on the offshore south Talara Basin, the whole
basin has received renewed interest for hydrocarbon exploration of Paleozoic.
116
Of especial interest is the interpretation of results in well La Casita drilled by Belco in a
syncline and that TD’d in Crystalline Granite Basement underlying Cretaceous
sediments. This well tested dry gas in Cretaceous and Tertiary sediments in a synclinal
area as seen on the TWT structural map of Paleozoic in the Bayobar Bay in Figure 88.
This area can be interpreted as a potential kitchen for the dry-gas production established
in the onshore Sechura Basin to the east. It must be mentioned here that the platform
selected to drill the original location could not spudded at the recommended site since a
water depth of 80 m. was found. The platform had to be moved to an area with water
depth of only 70 m., its maximum operational capacity (Ex-Belco Roger Palomino,
personal communication on January 31st, 2006, Houston). As seen in the mentioned
figure, the La Casita kitchen area is separated from the Tortuga Prospect by a large
normal listric fault that even cuts the Basement. This fault may have served as a barrier
for La Casita dry gas migration to the south and/or has served as a barrier for the oil
migration from San Pedro oil kitchens to the west and SW. This and other prospects and
leads in the area have also been exposed to any liquid hydrocarbons migrated from the
same western kitchens.
A series of prospects and leads encountered in the Talara Basin are described below
from south to north.
8.1.2.1. Calamar Lead
The Calamar Lead is located in the south Talara Basin within the western edge of the
shallow platform, on the west Bayovar Bay. This lead corresponds to an important
anticline structure associated with a listric normal fault (Figure 87). The exploration
targets within this lead are sequences of Paleozoic, Cretaceous and Tertiary age closely
related to potential Cretaceous and lower Tertiary source rocks within local kitchen
areas.
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Figure 87. Calamar Lead defined by seismic line RIB 93-16, showing the potential structural
configuration and explorations targets. More detail can be found in Appendix 3.
8.1.2.2. Caballa Prospect
The Caballa structure corresponds to a rollover anticline with four-way dip closure
associated with normal listric faults and with very good seismic definition (Figure 88,
Figure 89). It is located 22 Km. NW of the San Pedro oil discovery and some 16 Km. to
the west of the Tortuga Prospect. Belco drilled wildcat SBXA on the north flank of the
structure and TD’d in Cretaceous sediments. The main targets are the Paleozoic
metamorphic rocks.
Dimensions
?? Length N-S: +/- 8 km.
?? Width W-E: +/- 4 km.
Well defined by seismic Lines: PTP98-18, PTP98-38, PTP98-17, 93-22 and PTP99-43.
8.1.2.3. Tortuga Prospect
The Tortuga structure is located in the Bayovar Bay 15 Km NW of the San Pedro oil
discovery and 6 Km. SE of La Casita Well from which it is separated by a large normal
listric fault dipping to the NW. Tortuga is a prominent structural high with a very well
closure definition of nearly 100 Km2 (Figure 88, Figure 89). It corresponds to the
118
gravitational structures associated with normal and listric faults. The detachment level is
connected on the Basement. The main targets are also the Paleozoic metamorphic rocks.
Dimensions
?? Length W-E: +/- 12 km.
?? Width N-S: +/- 9 km.
Well defined by seismic Lines: PTP98-19, PTP98-39, PTP98-17, PTP98-40, and
PTP98-18.
Figure 88: Two-way time structural map on top of Paleozoic Basement, showing the in the
east the Tortuga prospect and in the west part, the Caballa structure.
Figure 89: West to East seismic line PTP 98-17, showing the Tortuga and Caballa structure.
See location on Figure 34.
119
8.1.2.4. Deeper Lobitos Paleozoic Lead
This lead is located on the offshore Lobitos High near to the LO9X well; whose TD is
within the Paleogene sequence at 1700 m. According to the seismic interpretation and
structural analysis, the Deeper Lobitos Paleozoic lead corresponds to anticlines found at
2.5 and 3 seconds TWT, these structures should target the Paleozoic and Cretaceous
sequences sealed by Paleogene sequences in or near the Talara Basin kitchen areas
(Figure 90).
Figure 90. Deeper Lobitos Paleozoic Lead defined by seismic line RIB 93-08, showing the
potential structural configuration and explorations targets. More detail can be found in
Appendix 3 and Enclosure 3p.
8.1.2.5. Mero Lead
The Mero Lead is located in ultra deep-water areas west of the Merluza lead where the
Talara Basin merges with the Tumbes Basin. This lead represents a new exploratory
play in the offshore deep platform of the Talara Basin. The structure corresponds to a
curved rollover anticlinal structure, associated to Talara listric normal fault developed
120
mostly in Tumbes Basin Neogene sediments (Figure 91). The potential reservoir targets
are in the Tumbes and Zorritos Formations and possibly in the Eocene series.
.
Figure 91. Mero Lead defined by seismic line RIB 93-05, showing the potential structural
Enclosure 3p.
8.1.2.6. Tiburon lead
This lead is representative of a new play type in ultra deep-water areas west of the
Lobitos High in the Deep Offshore Platform as seen on seismic line RIB 93-08 (Figure
92). The lead has a structural configuration related to a curved rollover anticlinal
structure associated with the Talara normal listric Fault. The exploration targets would
be within the Tertiary and Cretaceous sequences.
121
Figure 92: Tiburon Lead defined by seismic line RIB 93-08, showing the potential structural
Enclosure 3p.
8.1.2.7. Other prospects
Towards the south of the Paleogene Talara Basin, within the zone that could be
considered to be the transition into the Neogene Sechura Basin, important gravitational
rollover structures have been identified that could be highly prospective. These
structures are associated with normal listric faults that are connected to a deep
detachment in the Paleozoic and Crystalline Basement. The most important structures
are the San Pedro, San Pedro Este, rollover anticline and Paleozoic leads. The
exploration targets on these structures are mainly Paleozoic and the basal Talara
sequences.
122
8.2. Previously Defined Prospects and Leads
The description of previously defined prospects and leads are included in Appendix 4.
123
9.0. CONCLUSIONS
9.1. General
? ? All offshore development and exploratory drilling has been concentrated in
maximum water depths of less than 120 m (400 ft) in the Talara and Tumbes Basins.
A rough estimate places some 80% of the wells in water depths of less than 90 m in
the Talara Basin. Eighteen wells have been drilled in the offshore Tumbes Basin and
some 13,200 wells in the Talara Basin, including near 1,300 offshore wells.
? ? Cumulative production is about 1.4 BBO and 1.7 TCF in the Talara Basin and 100
MBO in the Tumbes Basin. Over 90% of the cumulative production was discovered,
developed and produced with no seismic data.
? ? Based on published literature mean estimated recoverable undiscovered
hydrocarbons in the Talara Basin are in the range between 2.2 to 1.71 BBO, 5.84 to
4.79 TCFG, and 255 MMB of NGL. These estimates are between 85 to 70%
offshore and between 15 to 30% onshore. Mean estimated recoverable undiscovered
oil, gas and natural gas liquids in the Tumbes (Peru) and bordering Progreso Basins
are 237 MMBO, 255 BCFG, and 32 MMB of NGL, respectively. These
undiscovered reserves include the 2,005 San Pedro oil discovery whose reserves are
being estimated in an area with several other similar structures.
9.2. Stratigraphy
? ? The Talara and Tumbes Basins developed as Paleogene and Neogene basins,
respectively. They include thick stratigraphic sequences of Paleozoic to Tertiary
ages that extend offshore and onshore along the Coastal region far beyond the
present basins. The pre-Tertiary interval is part of the regional sedimentary
succession characterizing all the Peruvian territory that eventually pinch out onto the
Brazilian and Guyana Shields. Some of the Paleogene Talara Basin extends north
under the Neogene Tumbes Basin, past the Peru-Ecuador border into the Santa
Elena Peninsula and overlies a regional incomplete Mesozoic Cretaceous basin
overlying a Paleozoic and Crystalline Basements best known in the Talara Basin
proper.
? ? The fill of the Talara and Tumbes basins is characterized by different stratigraphic
sequences associated with significant tectonic events and sea level global changes,
which generated erosional surfaces, changes in the depositional environment, rate of
sedimentation and depocenter migration. The stratigraphic architecture reflects
shifts in basin accommodation space, which derives from the interplay of
extensional tectonics, sediment supply and eustatic sea level changes. The internal
sequence architecture shows the retrogradational, progradational and agradational
stacking patterns.
? ? Sediment source for the Talara Basin to the east deposited from 9,700 to 7,900 m. of
sediments of Paleocene and Eocene ages above the Cretaceous in 35 my. An early
Oligocene section has been completed eroded off in the Talara Basin. The Tumbes
Basin was also the site of very rapid sedimentation of 6,600 m. to 7,200 m. of
Oligocene, Miocene and Pliocene sediments in 30 my.
9.3. Tectonics
? ? The Talara and Tumbes basins developed as a forearc basin system in the NW
coastal Peruvian Andes during Paleogene and Neogene times. The modern structural
124
??
??
??
??
??
??
occurrences in the Oligo-Miocene sequences of the Tumbes Basin. Few fields
produce from fractured metamorphic and metasediments of the Paleozoic Amotape
Formation and sandstones of Cretaceous and Paleocene age in the Talara Basin.
The late Cretaceous to early Eocene stratigraphic section dated by biomarker
Oleanane includes the most likely source rock of the major petroleum system that
accounts for the giant oil accumulation in the Talara Basin.
The interpreted geohistory modeling, oil occurrences and production data point
towards the presence of more than one hydrocarbon kitchen, very likely representing
major kitchens for the Talara and Tumbes Basins. Source rocks are interpreted to
contain adequate organic contents and have reached best maturity conditions along
the western deep and/or offshore portions of the whole Talara Basin and on deep
depocenters to the east and south of the Banco Peru in the Tumbes Basin.
Basin modeling was conducted on four wells in the Talara Basin and two wells and
a Pseudowell in the offshore Tumbes Basin.
Mid to Late Mature Windows characterize the Cretaceous and post-Cretaceous
sequences, whereas High post-mature values of Ro characterize the Paleozoic
metamorphosed sediments in the Lomitos oil field in the Talara Basin. Modeling
suggests that source rocks reached a late maturity stage and generated hydrocarbons
from late Eocene to early Oligocene time in the Talara Basin. Hydrocarbons were
expelled to the east into offshore/onshore traps, possibly former anticlines, during
Oligocene time before major tectonics faulted the original traps into the numerous
smaller blocks with sealing faults.
Any of the liquid hydrocarbons found in the Bayovar Bay must have migrated long
distances and have been generated from source rocks with different organic contents
than those found in La Casita 55X well. The regional modeling indicates that the
major synclinal area where the well is located may correspond to a dry gas kitchen
that generated the dry gas tested in this well in the Cretaceous and Tertiary
sandstone reservoirs and in the onshore Sechura Basin in Verdun sands.
Basin modeling has limitations in the offshore Tumbes Basin due to lack of
complete Geochemical analyses and of reliable recognition of the undrilled preOligocene stratigraphic column and its geological events. Basin modeling in wells
Barracuda with oil test in Cardalitos and Corvina with gas in Zorritos yields
immature burial for the known source rocks of Oligocene/Miocene ages. A
postulated upper Eocene Formation entered the mid mature oil window in late
Neogene. Pseudowell 1 in an interpreted kitchen has source rocks of various
formations in the Mid Mature to Main Gas Generation Windows, conditions
acquired from early Neogene to present.
9.5. Prospects and Leads
? ? Six and thirteen prospects and leads have been documented in offshore portions of
the Talara and Tumbes Basins, respectively. They have excellent potential to target
extensive stratigraphic columns of Paleozoic, Cretaceous, Eocene and OligoMiocene in or near interpreted kitchen areas and in water depths between 100 to
over 2,000m. Of especial interest are those defined in open areas or in areas where
exploration license contracts have not been signed yet.
? ? Recent oil discovery in the San Pedro 1X well in the south offshore Talara Basin in
conjunction with other existing Paleozoic oil fields as Laguna in the Pena Negra/El
Alto High in the extreme north onshore Talara Basin, has renewed interest for
hydrocarbon exploration of Paleozoic rocks in the whole NW Peru. There is a
highly attractive area for pre-Eocene, Cretaceous and Paleozoic exploration in the
126
configuration is related to a complex geodynamic history associated with the
interaction of the tectonics, eustatic and sedimentary processes that is controlled by
the direction and velocity of the relative subduction of the oceanic crust, the
aseismic subduction ridges and mainly by the Andes Mountain building processes.
Both basins have onshore and offshore components and are bounded on their ocean
side by a subduction complex wedge and on its landward side by the Amotape
Mountains.
? ? The present-day structural configuration of the Talara Basin is the result of complex
extensional and gravitational tectonics that occurred since Paleocene and mainly
during middle Eocene time, with reactivation in Neogene time. Most of the offshore
portion presents a shallow platform where all drilling activity has been carried out
and a deep platform, which has little seismic data.
? ? The structural style of the Neogene Tumbes basin is the result of a NW regional tilt
associated with the Banco Peru Fault, the south extension of the Dolores-Guayaquil
mega shear. The net result is the formation of gravitational tectonic structures,
which have generated both curved and planar rollover anticline structures and some
rotated fault blocks. These structures are associated to listric normal faults dipping
to the NW down to basin, with detachment levels at the base of the Heath Formation
and Pre Mancora series.
? ? The major period of development for these gravitational structures occurred during
the deposition of the Mal Pelo and La Cruz formations (Pliocene Pleistocene times).
In the present time, the Tumbes basin has the configuration of a major half graben
with the thickest section controlled by the Banco Peru Fault. Many of the structures
in the Tumbes basin are currently active as indicated by the recent deformation of
the younger sedimentary deposits.
9.4. Petroleum Systems and Basin Modeling
? ? Few regional Geochemical studies have been conducted in the Talara and Tumbes
Basins to clearly define the petroleum systems. This effort is still incomplete to
clearly recognize all the elements responsible for the giant oil accumulation in the
Talara Basin and the hydrocarbon occurrences in the Tumbes Basin.
? ? Main potential source rocks include the Redondo Formation of CampanianMaastrichtian age, Muerto Formation of Albian age and Paleocene and Eocene
Formations in the Talara Basin. The Cretaceous Redondo Formation constitutes a
source rock with TOC of 1 wt%, Type II/III Kerogen, oil and gas generator with
high thermal maturity corresponding to the last stage of the oil window in the Talara
Negritos High. The Muerto Formation has TOC from 1 to 4.5 wt%, excellent
RockEval character, Type II and II/III Kerogen, Tmax of 445 to 460 ºC, equivalent
Ro is 1 to 1.35 % in the adjacent Lancones Basin. Source rocks in the Muerto and
Redondo Formations are rich enough to have generated the commercial amounts of
hydrocarbons already produced in the oil fields of the Talara Basin in addition to a
sizeable amount of undeveloped reserves and as of yet, undiscovered reserves
onshore and offshore.
? ? Source rocks in the Tumbes Basin include Eocene Formations, Oligocene Mancora
Formation, Oligocene/Miocene Heath Formation and Miocene Zorritos and
Cardalitos Formations. TOC values in excess of 1.0 wt% are found in samples from
these formations with Type II and III Kerogen and subordinated Type I and poor
maturity.
? ? The main oil and gas reservoirs are sandstones interbedded with shale seals in both
the whole prolific Eocene sequences in the Talara Basin and in the hydrocarbon
125
areas between the shallow and deep platforms in the Talara Basin. The Deeper
Lobitos Paleozoic Lead in the Lobitos High and the Calamar Lead west of the
Bayovar Bay are two examples on this highly prospective area.
? ? The Banco Peru offers a large prospective area (larger than the Talara Negritos High
= 600+ MMBO cumulative production) with a large portion in shallow waters of
less than 100m. The Banco Peru has a core with dense rocks, which based on its
tectonic history gives potential for exploration of both fractured Paleozoic(?)
reservoirs and of the interpreted Cenozoic sequences especially in its eastern border
faulted by the Banco Peru Fault. This lead is conveniently located to receive
hydrocarbons from the Tumbes Basin kitchens. The stratigraphic sequences west of
the Banco Peru show less defined chaotic structures.
127
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Andes of Colombia. Geology, 14, 415-418.
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deformation in the Oriente Basin of Ecuador. Fourth International Symposium on
Andean Geodynamics, pp. 68-72.
5. Belco Petroleum Corporation (1975), Well Reports La Casita Z-2-75-55X.
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6. Daly M.C. (1989). Correlations between Nazca/Farallon plate kinematics and
forearc basin evolution in Ecuador. Tectonics, 8, 4, 769-790.
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Integrated Characterization of Neogene Oil and Gas Reservoirs, Progreso Basin,
Offshore Ecuador & Peru: Implications for Petroleum Exploration and Exploitation.
Perupetro S.A. INGEPET 2005.
8. DeMets C., Gordon R.G., Argus D.F. & Stein S. (1990). Current plate motions.
Geophys. J. Intl., 101, 425-478.
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cordilleraine : les Andes d.Equateur. Thèse de doctorat, Université de Paris Sud
Orsay, 167 p.
10. Esso Production Reasearch (1967), Organic Geochemical Analyses on 12 Cuttings
Samples from One Well (EPF RT-65) in Northwest Peru. Perupetro S.A. Technical
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11. Fildani A., Hanson D.H., Zhengzheng C., Moldowan J.M., Graham S.A. and Arriola
P.R. (2005) Geochemical characteristics of oil and source rocks and implications for
petroleum system, Talara Basin, northwest Peru. AAPG Bull. V. 89, No. 11.
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London, 129, 93-131.
13. Gonzales, E, and Alarcón, P. (2002). Potencial Hidrocarburifero de la Cuenca
Talara. INGEPET 2002.
14. Graña y Montero Petrolera S. A. (2003). Geochemical Survey in the La Cruz
District, Near the Zorritos Oil Field, Peru. A Passive Soil Gas Geochemical
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16. Herron E.M. (1972). Sea-floor spreading and the Cenozoic history of the EastCentral Pacific. GSA Bull., 83, 1671- 1692.
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128
18. Higley, D. (2001). The Talara Basin Province of Northwestern Peru: CretaceousTertiary Total Petroleum System (608101). Partial Report of the World Energy
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19. Higley, D. (2001). The Progreso Basin Province of Northwestern Peru and
Southwestern Ecuador: Neogene (608301) and Cretaceous-Paleogene (608302)
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Geological Survey.
20. Jordan T., B. Isacks R. Allmendinger J. Brewer V. Ramos et Ando C. (1983).
Andean tectonics related to geometry of the subducted Nazca plate, Geol. Soc. Am.
Bull., 94, 341-361, 1983.
21. Lonsdale P. (1978). Ecuadorian Subduction System. AAPG Bull. 62, 12, 24542477.
22. Macellari Carlos, (1985). Cretaceous Basins of Western South America. University
of South Carolina, Earth Resources Institute Volumes I and II.
23. Mammerickx J., Herron E.,& Dorman L. (1980). Evidence for two fossil spreading
ridges in the southeast Pacific. Geol. Soc. Am. Bull., 1, 91, 263-271.
24. Manrique C., P (1994). Interpretación Estructural y Posibilidades Petrolíferas del
Area Carpitas. GMP S.A. Exploration Department.
25. McIntosh, K.D., Silver, E.A., and Shipley, T., (1993). Evidence and mechanisms for
forearc extension at the accretionary Costa Rica convergent margin. Tectonics,
12:1380-1392.
26. Minster J.B. & Jordan T.H. (1978). Present day plate motions. J. Geol. Res., 83,
5331-5354.
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Characterization. Perupetro S.A. Technical Archive IT 03810
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Perú. Perupetro Technical Archive ITP21932.
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RT-48, Perú. Perupetro Technical Archive.
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Archive ITP 21693 to 21695. Segundo Período ITP 21771.
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Hidrocarburos en el Lote Z1, Perú. Pozos Corvina 40-10X, Albacora 8-X4,
Albacora 8 X5, Delfín 39 X1 y Barracuda X1. Perupetro S.A. Technical Archive
ITP 21697.
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IT00976.
129
38. Petroperu S.A. (1990). Proyecto Laguna Zapotal, Informe Final, Primera Parte.
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130
APPENDIX 1
Geochemical Database Offshore and Onshore
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2236
2237
2238
2239
2240
2241
2242
2262
2263
2264
NOA-98-001
NOA-98-002
NOA-98-003
NOA-98-004
NOA-98-006
NOA-98-007
NOA-98-008
NOA-98-009
NOA-98-010
NOA-98-011
NOA-98-012
NOA-98-013
NOA-98-014
NOA-98-015
NOA-98-016
NOA-98-017
NOA-98-018
NOA-98-019
NOA-98-021
NOA-98-022
NOA-98-023
NOA-98-024
NOA-98-025
NOA-98-026
NOA-98-047
NOA-98-048
NOA-98-049
NOA-98-050
NOA-98-051
NOA-98-052
NOA-98-053
NOA-99-062
NOA-99-063
NOA-99-064
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Well/Outcrop
PA-1
Qda. Gramadal
Qda. Gramadal
Qda. Gramadal
Qda. Gramadal
Qda. El Cortado
Qda. El Cortado
Qda. El Cortado
Qda. El Cortado
Qda. Pocitos
Qda. Pocitos
Qda. Pocitos (margen izquierda)
Qda. Pocitos (margen derecha)
Qda. Chapamgo (margen derecha)
Qda. Jaguay Negro
Afluente Qda. Jaguay Negro
Qda. Jaguay de Poechos
Qda. Jahuay de Poechos
Qda. Corcovado
Qda. Corcovado
Qda. El Cortado
Qda. El Cortado
Qda. El Cortado
Anticlinal de Pocitos
Qda. Pocitos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
SAMPLE
Depth (m) /
Ident.
524000
524100
524050
524020
519083
519170
519285
520795
525080
524960
524960
524250
524000
555690
555660
555540
555230
555010
523830
545160
545280
545470
545790
04°37´33.5"
04°37´33.5"
04°37´3.6"
04°37´14.2"
04°37´20.11"
04°36´21.2"
04°37´26.5"
558 745
558 745
558 745
FORMATION EQUIVALENT FORMATION FORMACIÓN
Original Report
(or correction)
EQUIVALENTE
(o corrección)
Huasimal
9510750
9510700
9510710
9510400
9489400
9489408
9489200
9489056
9493390
9493160
9492590
9491850
9492330
9509660
9509790
9510210
9509940
9509550
9489810
9484790
9484710
9484750
9484630
80°48´48.4"
80°48´48.4"
80°49´38.8"
80°49´37.7"
80°49´38"
80°47´13.8"
80°46´47.1"
9546 550
9546 550
9546 550
Huasimal
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Pocitos
Muerto
Muerto
Muerto
Muerto
Huasimal
Huasimal
Huasimal
Huasimal
Huasimal
Pocitos
Venados
Venados
Venados
Verdun
Cardalitos
Cardalitos
Pananga-Muerto
Muerto
Muerto
Muerto
Muerto
Redondo
Redondo
Redondo
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Huasimal
Huasimal
Huasimal
Huasimal
Huasimal
Muerto
Huasimal
Huasimal
Huasimal
Verdun
Talara?
Talara?
Pananga-Muerto
Muerto
Muerto
Muerto
Muerto
Redondo
Redondo
Redondo
TOC
(%)
1.10
1.81
0.92
2.04
2.87
1.89
4.59
4.19
2.64
3.79
2.19
1.37
2.22
0.56
0.39
0.39
0.34
0.23
0.22
0.85
0.63
1.21
0.37
0.82
1.71
1.66
3.07
4.15
2.02
4.32
1.23
1.05
0.91
1.18
APPENDIX 1
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2229
2230
2231
2232
2233
2234
2235
2251
2276
2277
NOA-99-065
NOA-99-066
NOA-99-067
NOA-99-068
NOA-99-069
NOA-99-070
NOA-99-071
NOA-99-072
NOA-99-073
NOA-99-074
NOA-99-075
NOA-99-080
NOA-99-081
NOA-99-082
NOA-99-083
NOA-99-084
NOA-99-085
NOA-99-086
NOA-99- 087
NOA-99-088
NOA-99-089
NOA-99-090
NOA-99-091
NOA-99-092
NOA-98-038
NOA-98-039
NOA-98-042
NOA-98-043
NOA-98-044
NOA-98-045
NOA-98-046
NOA-98-041
N0A-99-076
NOA-99-077
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Lancones
Tumbes
Tumbes
Tumbes
Tumbes
Tumbes
Tumbes
Tumbes
Tumbes
Tumbes
Tumbes
Well/Outcrop
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Cazaderos
Qda. Ñoquetes
Qda. Ñoquetes
Qda. Ñoquetes
Qda. Ñoquetes
Qda. Ñoquetes
Qda. Caballo Muerto
Qda. Caballo Muerto
Qda. Caballo Muerto
Qda. Caballo Muerto
Qda. Caballo Muerto
Qda. Tamarindo
Qda. Tamarindo
Carretera Venados - Nvo. Lancones
Entre Qdas. Mancora y Plateritos
Entre Qdas. Mancora y Plateritos
Qda. Lavejal
Qda. Lavejal
Qda. Lavejal
Qda. Cardalitos Rubio y Zorritos
Qda. Cardalitos Rubio y Zorritos
Desemb. Plateritos margen derecha
Qda. Bocapan
Qda. Bocapan
SAMPLE
Depth (m) /
Ident.
558 745
558 745
558 745
558 747
558 747
558 747
558 747
558 747
558 747
558 747
558 750
523 780
523 794
523 837
523 913
524 070
524 751
524 784
524 706
524 760
524 771
556 590
556 620
554 780
04°03'28.5''
04°03´28,5"
03°50´21.8"
03°50´21.8"
03°50´21.8"
03°45´44.7"
03°45´44.7"
03°53´47.9"
534 580
534 590
Original Report
(or correction)
EQUIVALENTE
(o corrección)
9546 550
9546 550
9546 550
9546 504
9546 504
9546 504
9546 504
9546 504
9546 504
9546 504
9546 550
9494 960
9494 941
9494 988
9494 763
9494 530
9493 834
9493 840
9493 775
9493 807
9493 650
9495 780
9495 710
9493 960
80°58'39.2''
80°58´33,2"
80°48´51.5"
80°48´51.5"
80°48´51.5"
80°47´26.5"
80°47´26.5"
80°50´50.5"
9578 430
9578 450
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Huasimal
Huasimal
Huasimal
Horquetas
Horquetas
Muerto (Mb. Superior)
Venados
Venados
Venados
Heath
Heath
Heath
Heath
Heath
Cardalitos
Cardalitos
Mancora
Heath
Heath
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Huasimal
Huasimal
Huasimal
Huasimal
Huasimal
Muerto
Muerto
Muerto
Muerto
Muerto
Huasimal
Huasimal
Huasimal
Heath
Heath
Heath
Heath
Heath
Cardalitos
Cardalitos
Mancora
Heath
Heath
TOC
(%)
1.29
1.88
1.05
1.22
0.81
1.04
1.32
1.02
0.89
0.96
0.80
0.86
0.56
0.36
0.16
0.28
0.74
1.06
1.99
1.28
1.76
0.42
0.27
0.31
2.61
1.78
0.21
0.23
0.19
0.47
0.54
0.68
0.47
0.32
APPENDIX 1
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
2278
2279
101
102
103
104
105
201
202
203
204
205
301
302
601
1201
1202
1203
1204
2002
2003
2004
2243
2244
2245
2246
2247
2248
2249
2250
2252
2253
2254
2255
NOA-99-078
NOA-99-079
NON-98-029
NON-98-028
NON-98-027
NON-98-030
NON-98-031
NON-98-032
NON-98-033
NON-98-034
NON-98-035
NON-98-036
NON-98-037
NON-98-038
NON-98-098
NON-98-094
NON-98-095
NON-98-096
NON-98-097
MR-82-022
MR-82-024
MR-82-034
NOA-98-054
NOA-98-055
NOA-98-056
NOA-98-057
NOA-98-058
NOA-98-059
NOA-98-060
NOA-98-061
NOA-98-027
NOA-98-028
NOA-98-029
NOA-98-030
A
A
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
A
A
A
A
A
A
A
A
A
A
A
A
A
A
A
Tumbes
Tumbes
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Well/Outcrop
Qda. Bocapan
Qda. Bocapan
Viru - 4X -1
Viru - 4X -1
Viru - 4X -1
Viru - 4X -1
Viru - 4X -1
Viru - 5X -1
Viru - 5X -1
Viru - 5X -1
Viru - 5X -1
Viru - 5X -1
Viru - 69X-1
Viru - 69X-1
Venturosa 10-X1
Espectativa 1-X1
Espectativa 1-X1
Espectativa 1-X1
Espectativa 1-X1
Pta. Bayovar
Pta. Bayovar
Cerro Malabrigo
Qda. Sabila
Qda. Sabila
Qda. Sabila
Cerro La Mesa
Cerro La Mesa
Cerro La Mesa
Cerro La Mesa
Cerro La Mesa
Sur de Punta Blanca (500m.)
Sur de Punta Blanca (100m.)
Qda. al Este de Pta. Blanca
SAMPLE
Depth (m) /
Ident.
Original Report
(or correction)
EQUIVALENTE
(o corrección)
534 581
534 590
3802
2797
1810
4210
4805
8049
7822
7918
7796
7669
1820
3156
4829
5470
5201
4350
1956
9578 512
9578 490
05°40´21.5"
05°40´21.5"
05°40´21.5"
05°16´44.2"
05°16´44.2"
05°16´44.3"
05°16´37.3"
05°16´37.3"
490040
490030
491040
491240
79°40´50.6"
79°40´50.6"
79°40´50.6"
80°59´24"
80°59´24"
80°59´24"
80°59´25.3"
80°59´25.3"
9356220
9356350
9356960
9356910
8063
7828
7930
7811
7685
4834
5465
5200
4343
1951
Heath
Heath
Chira
Chira
Heath
Verdun
Copa Sombrero
Copa Sombrero
Copa Sombrero
Copa Sombrero
Copa Sombrero
Verdun
Chira
Verdun
Chira
Verdun
Chira
Chira
Montera
Verdun
Chira
Chicama
Sabila
Sabila
Sabila
La Mesa
La Mesa
La Mesa
La Mesa
La Mesa
Verdun
Verdun
Verdun
Verdun
Heath
Heath
Chira
Chira
Heath
Verdun
Copa Sombrero
Copa Sombrero
Copa Sombrero
Copa Sombrero
Copa Sombrero
Verdun
Chira
Verdun
Chira
Verdun
Chira
Chira
Montera
Verdun
Chira
Chicama
Chicama
Chicama
Chicama
La Mesa
La Mesa
La Mesa
La Mesa
La Mesa
Verdun
Verdun
Verdun
Verdun
TOC
(%)
0.15
0.84
3.08
1.21
1.05
0.61
0.87
0.82
0.83
1.51
0.12
0.11
2.13
1.12
3.58
1.14
1.69
1.25
0.70
0.12
0.91
0.09
0.97
0.87
0.60
0.04
0.07
0.06
0.05
0.05
0.37
0.57
0.07
0.06
APPENDIX 1
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
2256
2257
2258
2259
2260
2261
1
2
3
4
5
401
402
403
404
501
701
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
NOA-98-031
NOA-98-032
NOA-98-033
NOA-98-034
NOA-98-035
NOA-98-036
NON-98-022
NON-98-023
NON-98-024
NON-98-025
NON-98-026
NON-98-039
NON-98-040
NON-98-041
NON-98-042
NON-98-043
NON-98-078
NON-98-044
NON-98-045
NON-98-046
NON-98-047
NON-98-048
NON-98-049
NON-98-050
NON-98-051
NON-98-052
NON-98-053
NON-98-054
NON-98-055
NON-98-056
NON-98-057
NON-98-058
NON-98-059
NON-98-060
A
A
A
A
A
A
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
Sechura
Sechura
Sechura
Sechura
Sechura
Sechura
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Well/Outcrop
Punta Shode
Qda. al Sur de Qda. Nunura
Qda. al Sur de Qda. Nunura
Qda. al Norte de Qda. Nunura
Norte C° Illescas (Planta oleoducto)
Lomitos 3835
Lomitos 3835
Lomitos 3835
Lomitos 3835
Lomitos 3835
Sandino 6020
Sandino 6020
Sandino 6020
Sandino 6020
Peoco 3 - 1
PN-426
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
SAMPLE
Depth (m) /
Ident.
491356
488320
488930
488910
489016
492700
8442
8052
7186
5142
4195
5492
5495
5637
5639
3765
9262
7490
7288
7093
6886
6670
6670
6464
6464
6238
6238
6046
6046
5817
5395
5395
5146
5138
Original Report
(or correction)
EQUIVALENTE
(o corrección)
9356795
9354360
9353790
9353850
9353822
9359130
8450
8071
7201
5150
4212
Core #1
Core #1
5338
5640
3757
9264.3
7497
7293
7100
6894
6684
6684
6470
6470
6258
6258
6066
6066
5828
5406
5406
5160
5146
Verdun
Verdun
Verdun
Verdun
Verdun
Verdun
Muerto
Redondo *
Redondo
Petacas
Balcones
Petacas
Petacas
Petacas
Petacas
Redondo
Basal Salinas
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Monte Grande
Monte Grande
Monte Grande
Monte Grande
Monte Grande
Verdun
Verdun
Verdun
Verdun
Verdun
Verdun
Muerto
Redondo
Redondo
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Redondo
Gr. Salina
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Monte Grande
Monte Grande
Monte Grande
Monte Grande
Monte Grande
TOC
(%)
0.07
0.10
0.10
0.11
0.13
0.10
3.78
0.78
0.74
0.62
0.57
0.64
0.19
0.61
0.75
1.40
0.80
0.84
0.77
0.72
0.77
0.68
0.70
0.68
0.69
0.62
0.71
0.49
0.42
0.56
0.57
0.62
0.49
0.67
APPENDIX 1
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
901
902
903
904
905
906
1001
1002
1003
1004
1005
1006
1101
1102
1103
1104
1105
NON-98-061
NON-98-062
NON-98-063
NON-98-064
NON-98-065
NON-98-066
NON-98-068
NON-98-067
NON-98-070
NON-98-071
NON-98-072
NON-98-073
NON-98-074
NON-98-075
NON-98-076
NON-98-077
NON-98-133
NON-98-079
NON-98-080
NON-98-081
NON-98-082
NON-98-083
NON-98-084
NON-98-085
NON-98-086
NON-98-087
NON-98-088
NON-98-089
NON-98-090
NON-98-091
NON-98-092
NON-98-093
NON-98-161
NON-98-160
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Well/Outcrop
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3585
Lomitos 3770
Lomitos 3770
Lomitos 3770
Lomitos 3770
Lomitos 3770
Lomitos 3770
Lomitos 3980
Lomitos 3980
Lomitos 3980
Lomitos 3980
Lomitos 3980
Lomitos 3980
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
SAMPLE
Depth (m) /
Ident.
5138
4997
4997
4997
4787
4482
4104
4104
3895
3484
3269
3168
2958
2958
2772
2511
8395
4510
4510
4510
4153
4153
4153
7310
6889
6889
6889
6538
6538
8740
8508
8435
7857
8374
Original Report
(or correction)
EQUIVALENTE
(o corrección)
5146
5017
5017
5017
4804
4502
4124
4126
3911
3503
3289
3188
2978
2978
2792
2531
8402
4527
4527
4527
4166
4166
4166
7324
6905
6905
6905
6548
6548
8750
8516
8442
7853
8368
Monte Grande
Mal Paso
Mal Paso
Mal Paso
Mal Paso
Mal Paso
Mal Paso
Mal Paso
Balcones
Balcones
Balcones
Balcones
Balcones
Balcones
Balcones
Balcones
Pananga
(K) Redondo ?
(K) Redondo ?
(K) Redondo ?
(K) Redondo ?
(K) Redondo ?
(K) Redondo ?
(K) Redondo
(K) Redondo
(K) Redondo
(K) Redondo
(K) Redondo
(K) Redondo
Paleozoico
Muerto
Muerto
Tablones
Muerto
Monte Grande
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Pananga
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Redondo
Paleozoico
Muerto
Muerto
Tablones
Muerto
TOC
(%)
0.47
0.56
0.56
0.61
0.52
0.40
0.36
0.54
0.44
0.59
0.41
0.40
0.41
0.36
0.46
0.46
0.43
0.58
0.59
0.54
0.57
0.59
0.52
0.23
0.65
0.65
0.85
0.67
0.33
0.50
1.18
1.66
1.99
0.40
APPENDIX 1
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
1106
1107
1108
1109
1110
1111
1112
1113
1114
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1401
1402
1403
NON-98-159
NON-98-158
NON-98-157
NON-98-156
NON-98-155
NON-98-154
NON-98-153
NON-98-152
NON-98-151
NON-98-001
NON-98-003
NON-98-002
NON-98-004
NON-98-005
NON-98-006
NON-98-007
NON-98-008
NON-98-009
NON-98-010
NON-98-011
NON-98-012
NON-98-013
NON-98-014
NON-98-015
NON-98-016
NON-98-017
NON-98-018
NON-98-019
NON-98-020
NON-98-021
NON-98-069
NON-98-149
NON-98-148
NON-98-147
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Well/Outcrop
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 3990
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
Lomitos 4000
3635
3635
3635
SAMPLE
Depth (m) /
Ident.
8399
8411
8451
8477
8516
8590
8650
8654
8687
7126
7126
7126
7279
7279
7279
6616
6616
6616
7696
7696
7696
4334
4334
4334
5962
5962
5962
8611
8166
8166
8275
5196
5509
5619
Original Report
(or correction)
EQUIVALENTE
(o corrección)
8389
8406
8435
8479
8501
8585
8636
8650
8681
7141
7141
7141
7296
7296
7296
6629
6629
6629
7716
7716
7716
4354
4354
4354
5974
5974
5974
8620
8180
8180
8282
5202
5499
5621
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Montegrande
Montegrande
Montegrande
Redondo
Redondo
Redondo
Montegrande
Montegrande
Montegrande
Redondo
Redondo
Redondo
Mesa
Mesa
Mesa
Mesa
Mesa
Mesa
Pamanga
Redondo
Redondo
Muerto
Salina-Negritos
Salina-Negritos
Salina-Negritos
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Muerto
Monte Grande
Monte Grande
Monte Grande
Redondo
Redondo
Redondo
Monte Grande
Monte Grande
Monte Grande
Redondo
Redondo
Redondo
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Gr. Mal Paso
Pananga
Redondo
Redondo
Muerto
Gr. Salina
Gr. Salina
Gr. Salina
TOC
(%)
2.46
0.58
2.10
0.91
2.08
4.48
0.71
0.62
0.62
0.61
0.45
0.60
0.63
0.67
0.57
0.66
0.71
0.67
0.81
0.76
0.56
0.92
0.66
0.80
0.46
0.34
0.43
0.31
0.54
3.94
0.56
0.69
0.66
0.40
APPENDIX 1
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
1404
1405
1406
1407
1501
1502
1601
1602
1603
1604
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1801
1802
1803
1804
1805
1806
1807
NON-98-146
NON-98-145
NON-98-144
NON-98-143
NON-98-099
NON-98-100
NON-98-104
NON-98-103
NON-98-102
NON-98-101
NON-98-123
NON-98-124
NON-98-125
NON-98-126
NON-98-127
NON-98-128
NON-98-129
NON-98-130
NON-98-131
NON-98-122
NON-98-121
NON-98-120
NON-98-119
NON-98-118
NON-98-117
NON-98-116
NON-98-115
NON-98-106
NON-98-107
NON-98-108
NON-98-109
NON-98-110
NON-98-111
NON-98-112
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
P
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Talara
Well/Outcrop
3635
3635
3635
3635
Lomitos 4655
Lomitos 4655
Lomitos 4705
Lomitos 4706
Lomitos 4707
Lomitos 4708
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5164
5237
5237
5237
5237
5237
5237
5237
SAMPLE
Depth (m) /
Ident.
5746
6526
6840
6920
6902
6905
9172
9180
9493
9496
5675
5667
5657
5648
5633
5621
5610
5598
5144
5681
5689
5696
5709
5718
5726
5747
5748
10285
10279
9508
8480
8472
6900
6979
Original Report
(or correction)
EQUIVALENTE
(o corrección)
5735
6546
6855
6923
6905
6907
9165
9172
9490
9493
5667
5657
5648
5633
5621
5610
5598
5580
5527
5675
5681
5689
5696
5709
5718
5726
5737
10279
10273
9498
8472
8465
6979
6968
Mal Paso
Mal Paso
Redondo
Paleozoico
Gr. Mal Paso
Gr. Mal Paso
Muerto
Muerto
Paleozoico
Redondo
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Gr. Mal Paso
Gr. Mal Paso
Redondo
Paleozoico
Gr. Mal Paso
Gr. Mal Paso
Muerto
Muerto
Muerto
Redondo
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
Paleozoico
TOC
(%)
0.46
0.44
0.75
0.23
0.49
0.25
2.69
3.00
1.62
0.32
0.44
0.49
0.47
0.46
0.54
0.48
0.50
0.38
0.40
0.50
0.34
0.40
0.41
0.36
0.35
0.33
0.46
1.30
0.77
0.60
0.44
0.53
0.57
0.48
APPENDIX 1
DGSI DATA
ID
Nº Reg.
P/A
Basin
DGSI
original
1808
1809
1901
1951
2228
NON-98-113
NON-98-114
NOC-98-001
NON-98-132
NOA-98-037
P
P
P
P
A
Talara
Talara
Talara
Talara
Talara
Well/Outcrop
5237
5237
Lomitos 5663
Lomitos 6020
Secuencia intermedia C. Blanco
SAMPLE
Depth (m) /
Ident.
6488
6480
5500
8103
04°15'18.6''
Original Report
(or correction)
EQUIVALENTE
(o corrección)
6480
6472
5530
8100
81°13'33.1''
Paleozoico
Paleozoico
Paleozoico
Sandino
Cabo Blanco
Paleozoico
Paleozoico
Paleozoico
Redondo
Pariñas
TOC
(%)
0.45
0.38
0.49
0.52
0.40
S1
S2
S3
Tmax
S1/TOC S2/TOC S3/TOC
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IO
IP
(%)
(%)
0.12
0.79
0.19
0.46
0.86
0.70
1.25
0.71
0.17
0.86
0.07
0.16
0.74
0.03
0.77
2.67
0.59
2.71
4.69
2.68
8.85
7.95
10.56
7.30
0.79
0.59
2.28
0.13
0.22
0.26
0.25
0.29
0.30
0.29
0.50
0.47
0.43
0.25
0.81
0.54
0.25
0.29
448
454
444
452
452
452
445
444
416
449
444
450
454
484
0.11
0.44
0.21
0.23
0.30
0.37
0.27
0.17
0.06
0.23
0.03
0.12
0.33
0.05
70.00
147.51
64.13
132.84
163.41
141.80
192.81
189.74
400.00
192.61
36.07
43.07
102.70
23.21
20.00
14.36
27.17
14.22
10.45
15.34
10.89
11.22
16.29
6.60
36.99
39.42
11.26
51.79
3.50
10.27
2.36
9.34
15.63
9.24
17.70
16.91
24.56
29.20
0.98
1.09
9.12
0.45
0.13
0.23
0.24
0.15
0.15
0.21
0.12
0.08
0.02
0.11
0.08
0.21
0.25
0.19
0.00
0.00
0.00
0.13
0.04
0.07
0.27
0.21
0.80
498
527
498
0.00
0.00
0.00
15.29
6.35
5.79
31.76
33.33
66.12
0.48
0.19
0.09
0.00
0.00
0.00
0.09
0.24
0.24
0.68
1.58
0.45
1.28
0.00
0.06
0.03
0.46
0.40
5.46
6.35
4.89
8.69
2.56
9.00
0.16
0.20
0.17
0.97
0.22
0.24
0.27
0.49
0.50
0.35
0.50
0.75
0.20
0.22
0.15
489
423
425
446
445
444
446
498
474
436
471
0.11
0.14
0.14
0.22
0.38
0.22
0.30
0.00
0.06
0.03
0.39
48.78
319.30
382.53
159.28
209.40
126.73
208.33
13.01
19.05
18.68
82.20
26.83
14.04
16.27
15.96
12.05
17.33
11.57
60.98
19.05
24.18
12.71
1.82
22.75
23.52
9.98
17.38
7.31
18.00
0.21
1.00
0.77
6.47
0.18
0.04
0.04
0.12
0.15
0.15
0.12
0.00
0.23
0.15
0.32
0.89
3.46
0.78
3.17
5.55
V ?1.19
3.38
10.10 B ?1.36
8.66
10.73
8.16 B ?1.42 V ?1.22
0.86
0.75
3.02
0.16
0.13
0.04
0.07
0.49
5.70
V ?0.38
6.59
V ?0.39
5.57
10.27 B ?1.41
3.01
V ?1.48
10.28 B 1.46
0.16
0.26
0.20
1.43
S1
S2
S3
Tmax
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IO
IP
(%)
(%)
0.70
0.14
1.15
0.84
0.46
0.36
1.58
0.87
0.65
0.67
0.05
0.08
0.11
0.81
0.53
0.63
0.91
0.47
0.42
1.07
0.90
0.52
0.63
0.05
0.39
0.24
0.19
0.51
0.21
0.17
0.13
0.15
0.13
0.12
0.19
0.11
0.24
0.11
0.02
445
466
473
469
477
461
469
469
474
421
350
459
457
0.54
0.07
1.10
0.69
0.57
0.35
1.20
0.85
0.73
0.70
0.06
0.09
0.20
62.79
28.19
60.00
74.59
58.02
40.38
81.06
88.24
58.43
65.63
6.25
45.35
42.86
14.73
27.13
20.00
13.93
16.05
14.42
9.85
11.76
21.35
11.46
30.00
12.79
3.57
4.26
1.04
3.00
5.35
3.62
2.80
8.23
7.50
2.74
5.73
0.21
3.55
12.00
0.46
0.21
0.65
0.48
0.49
0.46
0.60
0.49
0.56
0.52
0.50
0.17
0.31
1.51
0.67
1.78
1.75
0.93
0.78
2.65
1.77
1.17
1.30
0.10
0.47
0.35
0.30
0.03
0.72
0.26
0.15
0.00
0.34
0.19
2.63
0.68
0.75
0.00
0.16
0.45
0.29
0.36
0.46
0.14
454
463
451
445
446
N.A.
0.41
0.03
0.36
0.20
0.09
0.00
45.95
17.92
132.16
53.13
42.61
0.00
21.62
42.45
14.57
28.13
26.14
33.33
2.13
0.42
9.07
1.89
1.63
0.00
0.47
0.14
0.21
0.28
0.17
0.64
0.22
3.35
0.94
0.90
0.00
0.21
0.11
9.64
4.84
0.47
1.36
415
412
0.08
0.06
369.35
271.91
18.01
76.40
20.51
3.56
0.02
0.02
9.85
4.95
0.08
0.03
0.02
0.03
0.22
0.21
0.06
0.15
1.30
0.34
0.05
0.06
438
421
518
433
0.17
0.06
0.03
0.06
46.81
38.89
8.82
31.91
276.60
62.96
7.35
12.77
0.17
0.62
1.20
2.50
0.27
0.13
0.25
0.17
0.30
0.24
0.08
0.18
V ?1.71
V 1.67
S1
S2
S3
Tmax
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IP
(%)
(%)
IO
0.01
0.31
0.06
0.12
0.03
0.02
0.05
0.03
0.07
0.42
6.04
0.41
0.72
0.21
0.04
0.24
0.09
0.16
0.15
2.13
1.35
1.14
0.61
1.90
0.10
0.07
0.09
472
419
410
438
472
427
494
518
532
0.01
0.10
0.05
0.11
0.05
0.02
0.06
0.04
0.05
50.00
196.10
33.88
68.57
34.43
4.60
29.27
10.84
10.60
17.86
69.16
111.57
108.57
100.00
218.39
12.20
8.43
5.96
2.80
2.84
0.30
0.63
0.34
0.02
2.40
1.29
1.78
0.02
0.05
0.13
0.14
0.13
0.33
0.17
0.25
0.30
0.43
6.35
0.47
0.84
0.24
0.06
0.29
0.12
0.23
0.24
0.04
0.39
0.04
0.14
0.07
0.02
1.66
0.75
7.49
0.39
2.04
0.70
0.29
2.15
1.21
4.45
1.70
1.31
1.24
4.42
405
425
416
419
423
425
467
0.11
0.04
0.11
0.04
0.08
0.06
0.03
77.93
66.96
209.22
34.21
120.71
56.00
41.43
100.94
108.04
124.30
149.12
77.51
99.20
631.43
0.77
0.62
1.68
0.23
1.56
0.56
0.07
0.13
0.05
0.05
0.09
0.06
0.09
0.06
1.90
0.79
7.88
0.43
2.18
0.77
0.31
0.03
0.15
0.29
490
0.03
16.48
31.87
0.52
0.17
0.18
0.00
0.00
0.00
0.01
0.02
0.09
0.15
0.25
0.16
425
429
521
0.00
0.00
0.00
1.03
2.30
15.00
15.46
28.74
26.67
0.07
0.08
0.56
0.00
0.00
0.00
0.01
0.02
0.09
0.00
0.03
0.03
391
0.00
5.26
5.26
1.00
0.00
0.03
V ?0.27
V ?3.20
V ?0.23
V ?0.34
V ?0.32
V ?0.27
V 4.16
S1
S2
S3
Tmax
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IO
IP
(%)
(%)
B 1.41
V 0.37
1.64
0.20
0.02
0.00
0.00
0.02
5.14
0.53
0.21
0.33
0.09
0.26
0.69
0.33
0.10
0.09
0.12
0.04
442
444
514
566
545
471
0.43
0.26
0.03
0.00
0.00
0.03
135.98
67.95
28.38
53.23
15.79
40.63
18.25
42.31
13.51
14.52
21.05
6.25
7.45
1.61
2.10
3.67
0.75
6.50
0.24
0.27
0.09
0.00
0.00
0.07
6.78
0.73
0.23
0.33
0.09
0.28
0.01
0.00
0.31
0.05
0.01
0.00
0.00
0.00
0.01
0.00
0.02
0.02
0.03
0.01
0.03
0.00
0.04
0.00
0.01
0.02
0.01
0.19
0.20
1.27
0.27
0.24
0.13
0.18
0.20
0.23
0.25
0.24
0.25
0.29
0.26
0.27
0.10
0.28
0.18
0.23
0.21
0.17
0.27
0.38
0.48
0.15
0.23
0.22
0.06
0.29
0.22
0.11
0.28
0.16
0.40
0.18
0.36
0.14
0.14
0.34
0.23
0.08
0.10
510
449
438
435
473
484
482
478
524
479
522
487
483
473
475
454
478
491
504
474
489
0.02
0.00
0.22
0.06
0.01
0.00
0.00
0.00
0.01
0.00
0.03
0.03
0.05
0.01
0.06
0.00
0.07
0.00
0.02
0.04
0.01
31.15
26.67
90.71
33.75
28.57
16.88
25.00
25.97
33.82
35.71
35.29
36.23
46.77
36.62
55.10
23.81
50.00
31.58
37.10
42.86
25.37
44.26
50.67
34.29
18.75
27.38
28.57
8.33
37.66
32.35
15.71
41.18
23.19
64.52
25.35
73.47
33.33
25.00
59.65
37.10
16.33
14.93
0.70
0.53
2.65
1.80
1.04
0.59
3.00
0.69
1.05
2.27
0.86
1.56
0.73
1.44
0.75
0.71
2.00
0.53
1.00
2.63
1.70
0.05
0.00
0.20
0.16
0.04
0.00
0.00
0.00
0.04
0.00
0.08
0.07
0.09
0.04
0.10
0.00
0.13
0.00
0.04
0.09
0.06
0.20
0.20
1.58
0.32
0.25
0.13
0.18
0.20
0.24
0.25
0.26
0.27
0.32
0.27
0.30
0.10
0.32
0.18
0.24
0.23
0.18
V 1.06
V ?1.57
V 1.11
V ?1.37
V 1.01
V 1.24
V 0.78
S1
S2
S3
Tmax
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IO
IP
(%)
(%)
0.03
0.01
0.03
0.03
0.03
0.00
0.24
0.13
0.21
0.24
0.12
0.08
0.10
0.21
0.32
0.24
0.31
0.08
483
481
490
476
479
483
0.06
0.02
0.05
0.05
0.06
0.00
51.06
23.21
37.50
39.34
23.08
20.00
21.28
37.50
57.14
39.34
59.62
20.00
2.40
0.62
0.66
1.00
0.39
1.00
0.11
0.07
0.13
0.11
0.20
0.00
0.27
0.14
0.24
0.27
0.15
0.08
0.00
0.00
0.01
0.00
0.00
0.02
0.10
0.12
0.23
0.12
0.13
0.16
0.26
0.28
0.28
0.09
0.09
0.12
466
475
487
505
479
508
0.00
0.00
0.02
0.00
0.00
0.05
18.52
27.27
38.98
29.27
32.50
39.02
48.15
63.64
47.46
21.95
22.50
29.27
0.38
0.43
0.82
1.33
1.44
1.33
0.00
0.00
0.04
0.00
0.00
0.11
0.10
0.12
0.24
0.12
0.13
0.18
0.00
0.00
0.01
0.01
0.02
0.00
0.02
0.02
0.02
0.05
0.11
0.03
0.09
0.12
0.05
0.05
0.11
0.14
0.09
0.09
0.20
1.08
0.94
0.77
0.61
0.41
0.41
461
486
384
437
435
436
404
442
458
0.00
0.00
0.02
0.02
0.03
0.00
0.04
0.03
0.04
10.87
23.91
6.98
15.52
20.34
9.26
8.77
18.64
26.92
19.57
19.57
46.51
186.21
159.32
142.59
107.02
69.49
78.85
0.56
1.22
0.15
0.08
0.13
0.06
0.08
0.27
0.34
0.00
0.00
0.25
0.10
0.14
0.00
0.29
0.15
0.13
0.05
0.11
0.04
0.10
0.14
0.05
0.07
0.13
0.16
0.06
0.04
0.05
0.03
0.16
0.18
0.36
0.10
0.27
0.24
0.24
0.45
480
449
473
514
0.09
0.06
0.06
0.04
24.62
27.69
42.35
14.93
41.54
36.92
28.24
67.16
0.59
0.75
1.50
0.22
0.27
0.18
0.12
0.23
0.22
0.22
0.41
0.13
0.01
0.34
0.48
0.96
0.02
0.04
1.40
2.57
3.87
0.09
0.02
0.21
0.34
0.20
0.11
493
445
440
436
470
0.02
0.29
0.29
0.48
0.05
8.00
118.64
154.82
194.47
22.50
4.00
17.80
20.48
10.05
27.50
2.00
6.67
7.56
19.35
0.82
0.20
0.20
0.16
0.20
0.18
0.05
1.74
3.05
4.83
0.11
V 0.95
V ?0.74
V 1.42
V 1.34
V ?1.19
V ?.82
S1
S2
S3
Tmax
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IP
(%)
(%)
IO
0.61
0.02
0.50
0.41
1.07
1.08
0.15
0.17
0.08
0.00
0.00
0.01
0.00
0.01
0.00
0.03
0.04
0.04
0.04
0.03
0.02
0.16
0.01
0.02
0.02
6.69
0.11
4.64
1.52
7.10
11.02
1.57
1.00
0.90
0.13
0.08
0.19
0.18
0.17
0.13
0.23
0.23
0.21
0.30
0.19
0.21
0.86
0.20
0.23
0.22
0.22
0.23
0.18
0.15
0.22
0.26
0.08
0.13
0.12
0.36
0.43
0.25
0.14
0.18
0.07
0.24
0.11
0.08
0.95
0.32
0.34
0.22
0.20
0.14
0.06
436
458
441
436
439
441
441
438
440
487
522
493
486
521
489
485
470
501
471
474
475
433
446
460
438
0.25
0.03
0.24
0.45
0.51
0.24
0.21
0.27
0.13
0.00
0.00
0.02
0.00
0.01
0.00
0.05
0.06
0.06
0.05
0.04
0.04
0.17
0.02
0.03
0.04
271.95
18.97
220.95
167.03
341.35
245.98
221.13
161.29
145.16
21.31
17.78
31.67
28.57
25.37
22.81
34.85
32.39
31.34
37.04
25.00
37.50
93.48
30.30
28.75
47.83
8.94
39.66
8.57
16.48
10.58
5.80
11.27
20.97
19.35
59.02
95.56
41.67
22.22
26.87
12.28
36.36
15.49
11.94
117.28
42.11
60.71
23.91
30.30
17.50
13.04
30.41
0.48
25.78
10.13
32.27
42.38
19.63
7.69
7.50
0.36
0.19
0.76
1.29
0.94
1.86
0.96
2.09
2.63
0.32
0.59
0.62
3.91
1.00
1.64
3.67
0.08
0.15
0.10
0.21
0.13
0.09
0.09
0.15
0.08
0.00
0.00
0.05
0.00
0.06
0.00
0.12
0.15
0.16
0.12
0.14
0.09
0.16
0.05
0.08
0.08
7.30
0.13
5.14
1.93
8.17
12.10
1.72
1.17
0.98
0.13
0.08
0.20
0.18
0.18
0.13
0.26
0.27
0.25
0.34
0.22
0.23
1.02
0.21
0.25
0.24
0.03
0.19
0.06
439
0.07
44.19
13.95
3.17
0.14
0.22
0.00
0.30
0.40
0.01
0.00
0.00
0.20
9.63
0.94
0.11
0.14
0.00
0.10
0.34
0.23
0.06
0.14
0.02
461
438
431
437
471
N.A.
0.00
0.08
0.71
0.01
0.00
0.00
37.04
244.42
167.86
15.94
21.21
0.00
18.52
8.63
41.07
8.70
21.21
5.00
2.00
28.32
4.09
1.83
1.00
0.00
0.00
0.03
0.30
0.08
0.00
0.20
9.93
1.34
0.12
0.14
0.00
V ?1.01
V 0.82
V ?0.85
V 0.57
S1
S2
S3
Tmax
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IO
IP
(%)
(%)
0.00
0.00
0.02
0.00
0.02
0.26
0.07
0.14
0.14
N.A.
414
428
0.00
0.00
0.03
0.00
4.55
34.67
15.22
31.82
18.67
0.00
0.14
1.86
0.00
0.07
0.00
0.02
0.28
V 0.78
0.05
0.27
0.07
484
0.10
55.10
14.29
3.86
0.16
0.32
V ?1.29
0.71
0.99
0.71
7.37
7.63
3.85
0.13
0.13
0.12
436
438
437
0.26
0.33
0.44
273.98
254.33
237.65
4.83
4.33
7.41
56.69
58.69
32.08
0.09
0.11
0.16
8.08
8.62
4.56
0.00
0.02
0.01
0.00
0.01
0.01
0.01
0.04
0.13
0.10
0.02
0.12
0.04
0.03
0.10
0.02
0.02
0.02
0.02
0.04
0.04
511
516
454
362
517
513
548
0.00
0.04
0.02
0.00
0.02
0.02
0.02
9.09
26.53
21.28
4.35
22.22
8.33
6.00
22.73
4.08
4.26
4.35
3.70
8.33
8.00
0.40
6.50
5.00
1.00
6.00
1.00
0.75
0.00
0.13
0.09
0.00
0.08
0.20
0.25
0.04
0.15
0.11
0.02
0.13
0.05
0.04
0.00
0.00
0.00
0.13
0.03
0.06
N.A.
543
0.00
0.00
0.00
26.00
7.50
12.00
0.00
2.17
0.00
0.00
0.13
0.00
0.00
0.10
0.02
0.10
0.05
489
519
0.00
0.00
25.00
4.88
25.00
12.20
1.00
0.40
0.00
0.00
0.10
0.02
0.00
0.00
0.01
0.01
0.00
0.00
0.01
0.00
0.06
0.01
0.08
0.00
0.01
0.00
0.00
0.00
0.05
0.17
0.03
0.03
0.03
0.03
0.03
0.02
527
540
547
N.A.
548
N.A.
N.A.
N.A.
0.00
0.00
0.01
0.02
0.00
0.00
0.02
0.00
13.04
0.77
10.39
0.00
2.27
0.00
0.00
0.00
10.87
13.08
3.90
5.00
6.82
5.66
5.26
4.17
1.20
0.06
2.67
0.00
0.33
0.00
0.00
0.00
0.00
0.00
0.11
1.00
0.00
0.06
0.01
0.09
0.01
0.01
0.00
0.01
0.00
1.00
V ?4.33
V ?5.04
S1
S2
S3
Tmax
S2/S3 S1/S1+S2 S1+S2
Ro B
Ro V
mg/g
mg/g
mg/g
ºC
IH
IP
(%)
(%)
IO
0.00
0.02
0.02
548
0.00
4.44
4.44
1.00
0.00
0.02
0.02
0.57
0.00
0.04
1.09
0.11
0.54
0.09
0.28
537
432
478
0.04
1.10
0.00
8.16
209.62
27.50
110.20
17.31
70.00
0.07
12.11
0.39
0.33
0.34
0.00
0.06
1.66
0.11
V 3.87
V ?0.62

PERUPETRO SA TUMBES AND TALARA BASINS

Transcripción

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