V INGEPET 2005 (EXPR-4-DU-14) ENE BASIN HYDROCARBON POTENTIAL Dennys E. Uyén ─ Pluspetrol Norte Abstract The Ene basin is located in the south east of Peru, approximately 300 km east from Lima, 100 km west from the Camisea area. According to the field geology data and the biostratigraphic studies, in the Ene basin has been identified sediments ranging in age from Ordovician to the present. From the structural point of view it is located in the thrusted and folded belt, between the eastern Andean chain and the foreland and there is a good correlation between the rate of convergence of the Nazca and South American plates and the evolution of the basin at least from Triassic-Jurassic times to the present. The petroleum system in this basin could be defined and characterized by Paleozoic source rocks, Cretaceous and Paleozoic reservoirs, sealed by interbedded shaly sequences and large, faulted and thrusted anticlines as traps. The Paleozoic formations with the best potential as source rocks are: the Permian Ene formation (related to some oils from Madre de Dios and Ucayali basins), the Lower Carboniferous Ambo Group (correlated with the gas and condensate fields from Camisea area) and the Devonian Cabanillas Group (related to some of the oils from Madre de Dios Basin). Additionally there is a possibility of the Triassic-Jurassic Pucará Group presence, which has been drilled in the well Oxapampa 7-1 and has been correlated with the oils of the southern Marañon basin and northern Ucayali basin. The sequences with the best characteristics as reservoirs are the Cretaceous Cushabatay, Agua Caliente and Vivian Formations with proved oil production in Oriente, Marañon and Ucayali basins with and upside potential of the Permian Mitu and Ene sandstone which produce gas and condensate in the Camisea area. The most conspicuous and regional seals are the Red Beds above the Vivian Formation, The limestone and shale of the upper Chonta Formation, The plastic shale of the Izcozacin Formation, above the Cushabatay Formation and the shaly sequences interbedded with the reservoirs in the Mitu and Ene Formations. The traps are constituted by large thrusted and faulted anticlines, historically related to the Andean tectonics evolution; the Quechua III tectonic phase is the responsible of the present structural configuration. Traces of residual hydrocarbons have been detected in Tertiary cutting samples obtained from seismic drilling holes on the western side of the line 109. According to preliminary modeling the hydrocarbon generation started at the beginning of the Paleocene age (65 my). The Ene basin is a high potential high-risk exploration area. • Field work geology in the central and northern part of the basin. PERU SEPA SATIPO CAMISEA M IPAYA-1 ENE BASIN Fig. 100 km west from the Camisea area. between the eastern Andean chain and the foreland. Figure 1. 1990 • Geochemical analysis (ROBERTSON RESEARCH). 1995-1999 (ELF LICENSE CONTRACT) • 5 350 km of Aerogravimetry/Aeromagnetometry. 1978 • Radar images 1:250 000 (AEROSERVICE). 1992-1993 (EUROCAN TEA) • 21 000 km2 of High Resolution Synthetic Aperture Radar (INTERA). • Petrophysical analysis (CORE LAB).Ene Basin Location Map Exploration History Several exploration campaigns have been carried out in this basin. 1995-1996 . • 5 058 km of Aeromagnetic data (GEONEX). • Geochemical analysis (DGSI). From the structural point of view it is located in the thrusted and folded belt. 1 .V INGEPET 2005 (EXPR-4-DU-14) 2 Introduction Location The Ene basin is located in the south east of Peru. approximately 300 km east from Lima. some of them are: 1965-1966 • Field work geology (IPC). (8x8 km grid). Silurian? Contaya Fig. Caliente Cenomanian Izcosacin Albian to Cenomanian Raya Aptian to Albian Cushabatay Jurassic Upper Jurassic to Sarayaquillo Neocomian? Upper Triassic to Pucara Lower Jurassic Upper Permian to Triassic Mitu Paleozoic Permian Ene Upper Carboniferous to Copacabana Lower Permian Upper Carboniferous Tarma Lower Carboniferous Ambo Upper Devonian Cabanillas Ordovician . • The Paleozoic thickness variations are mainly related to the presence of the unconformity between the Paleozoic and Mesozoic sediments (Tardi-Hercynian tectonics).V INGEPET 2005 (EXPR-4-DU-14) 3 • 267 km of 2D seismic.Ene Basin Stratigraphic Column Paleozoic • The oldest deposits recognized belong to the Ordovician Contaya Formation.Turonian A. 2 . • The Sarayaquillo Formation has larger distribution than the Mitu and Pucará Groups. • Field work geology (5 months in 1996). reservoir and biostratigraphic analysis. • Source rock. in the Ene basin. have been identified sediments ranging in age from Ordovician to the present. . • The Cretaceous sequence shows important lateral thickness variations with clear thinning from West to East in the central part of the basin. • 28 km of 2D seismic. A brief outline of the stratigraphy is summarized below and showed in the Figure 2. 1997 (220 km programmed). 1996 (400 km programmed). Cretaceous • The Cretaceous depocenter does not coincide with the axial part of the present day Ene basin. • There are few distribution control points. • Field work geology (3 months in 1997). AGE FORMATION LITHOLOGY T Lower Tertiary “REDBEDS” Maestrichtian to Huchpayacu Paleocene Cretaceous Campanian to Cachiyacu Maestrichtian Vivian Turonian to Chonta Lower Senonian Cenomanian . Triassic-Jurassic • The Mitu and Pucara Groups have been recognized in the northwestern part of the basin (Oxapampa well 7-1). Stratigraphy According to the field geology data and the biostratigraphic studies. However there are potential reservoirs in the Paleozoic sequence: Ene. • During the Peruana phase (Turonian-Upper Campanian) occurred the inversion of the previous tectonics features. • During the Incaica phase the basin was part of a foreland environment in a tectonic plate setting with oblique convergence direction (anomaly 18) that conducted to the opening of the strike slip basins. SEISMIC LINE 11 SW NE 1 Tertiary 2 Cretaceous 3 Paleozoic 4 SHIRA Fig. seismic. • From Triassic to early Cretaceous times the tectonic was mainly extensional. The formations with good reservoir characteristics have been identified in the Cretaceous sequence: Cushabatay. • There is a good correlation between the rate of convergence of the Nazca and South American plates and the tectonic evolution of the basin at least from Triassic-Jurassic times to the present. remote sensors and surface geology data. Chonta Basal and Vivian formations. The formations with the best potential as source rocks belong to the Paleozoic sequence: Cabanillas Group (Devonian). a structural style has been determined. However. Structure Based on aerogravimetric. magnetometric. since Miocene. (Fig. • The Mochica phase (Albian) was characterized by extensional movements associated with volcanism.V INGEPET 2005 (EXPR-4-DU-14) 4 Tertiary • Uncompleted section descriptions due to poor outcrop condition. it is possible to distinguish some influence of the Hercynian tectonics on the geometry of the Jurassic and Cretaceous basins. . Mitu and the Tarma basal sandstone formations. constitutes the main compressive event responsible for the present-day thin-skinned structural style of the basin.2D Seismic Line 11 showing a typical thin skinned structural style • The Paleozoic tectonic evolution of the basin is not completely understood because there is not enough data to describe it. 3) and a tectonic evolution of the basin is proposed. Agua Caliente. • The Quechua phase. 3 . Ambo Group (Lower Carboniferous) and Ene Formation (Permian). 0 13 1 2 3 4 5 6 7 8 9 10 SATIPO 8 4 MIPAYA-1 CAMISEA 2 ENE BASIN 15 7 1 12 12 11 TOC % 9 9 10 6 3 3 VERY GOOD GOOD POOR 40 Km. Figure 4. This Formation has been sampled in many locations around the Camisea area as well as in the Ene basin.6 SHIRA 0. additionally an organic rich shaly interval has been sampled in the lower part of the Cushabatay Formation in the Paucartambo-Villarica section and there is an strong seismic evidence that the Pucará Group is present in the western side of the basin.V INGEPET 2005 (EXPR-4-DU-14) 5 Source Rock Three potential source rocks have been identified in this basin: The Ene Formation (Permian). The Maximum Temperature values from pyrolysis are ranging from 432-440°C.4 INMATURE 6 0. 4 . Figure 4. o Ene Formation Composed of dark gray shale. 0 1 2 3 4 5 6 7 9 11 13 15 Fig.2 14 5 SEPA 0. Kerogen Type: The Hydrogen Index calculated from pyrolysis data varies from 350 to 745 mg HC/g TOC suggesting the presence of kerogen Type I . Figure 4. slightly calcareous interbedded with medium dark gray dolomitic limestone.8 OIL Ro % 0. fine grained white quartz sandstone and light gray to cream siltstone. 0. the Ambo Group (Lower Carboniferous) and the Cabanillas Formation (Devonian). Richness: The average TOC values for each of these locations span from 1 to 10%.7%. These values suggest an early to middle mature stage for the organic matter in the Ene Formation. argillaceous dolomite. Indicating that this Formation has a good to excellent quality as a potential source rock. Maturity: The Vitrinite reflectance values vary from 0.II with very good characteristics to generate liquid hydrocarbons.Organic richness and maturity level of the Ene Fm. .5 to 0. also the S2 parameter from pyrolysis ranges from 5 to 18 mg HC/g rock confirming that this Formation has a very good potential to generate hydrocarbons. Kerogen Type: The Hydrogen Index (48-52 mg HC/g TOC) suggests a kerogen type III.5 . Figure 6. It has been recognized and sampled in few locations. Maturity: The Vitrinite reflectance (0. with good potential to generate gas. o Cabanillas Group Thin interbedded dark gray to black shale.87%) and the S2 from pyrolysis (0.2% and the S2 values from 11 to 18 mg HC/g rock indicating that this formation has a good to very good potential to generate hydrocarbons.1 to 1. indicate that this Formation has a fair to good potential to generate hydrocarbons.2 SEPA 7 1 2 3 4 5 6 7 8 SATIPO 6 5 MIPAYA-1 CAMISEA ENE BASIN 4 10 2 TOC TOC%(%) 8 6 1 4 VERY GOOD 2 GOOD 0 POOR 40 Km. siltstone and coal with organic rich horizons. Richness: The TOC values (0. 1.65 to 8.34-0. The sampling locations are showed in the Figure 5. 1 2 3 4 5 6 7 8 Fig. Kerogen Type: The Hydrogen Index values for this formation (120-200 mg HC/g TOC). 6.9-1.3% and the Maximum Temperature from pyrolysis (443-458°C) indicate that the organic matter in this Formation is highly mature to generate liquid hydrocarbons. suggest the presence of a kerogen type II to III with good potential to generate oil and gas.6 INMATURE 8 0.0 SHIRA OIL 0. Fig. Figure 6.4 GAS Ro % 3 1. siltstone and mudstone deposited in a moderately deep- water environment. Figure 5.7 mg HC/g rock). .37%) and the Maximum Temperature from pyrolysis (453- 462°C). indicate that the organic matter in the Ambo Group is in the late mature stage of liquid hydrocarbons generation. Figure 5.65-0.V INGEPET 2005 (EXPR-4-DU-14) 6 o Ambo Group Composed of fluvial to shallow marine sandstone intercalated with thin layers of black to gray shale.Organic richness and maturity level of the Ambo Group Richness: The average TOC values for the sampled locations varies from 0. Maturity: The values of Vitrinite reflectance ranging from 1. 2 2 SHIRA 1. It could have been generated by different source rocks or from the same source rock at different maturity levels. it has not been possible to find a definitely correlation between these hydrocarbons and any of the potential source rocks present in the basin. • Non-fluorescent and low reflectivity bitumen (0.4 GAS Ro % 1. Due to the poor biomarker information.6 SEPA 1 2 3 SATIPO 3 3 MIPAYA-1 CAMISEA ENE BASIN 1. The carbon isotope value of the total extract is –27% PDB.0 OIL 0.Organic richness and maturity level of the Cabanillas Group Migrated Hydrocarbons Traces of residual hydrocarbons have been detected in Tertiary cutting samples (MIY 532 and 533) obtained from seismic drilling holes on the western side of the line 109 (SP 2433 and 2441). • Low reflectivity bitumen (0.7-0. Figure 7.9 % equivalent Ro.0 TOC % 0. The biomarker information suggests that these hydrocarbons were generated from a shaly carbonated source rock with maturity level of 0. Three hydrocarbon families have been differentiated based on their maturity state of evolution: • High reflectivity bitumen (1% reflectivity).15% reflectivity).8 0.2 40 Km. 6 .0 1 2 3 Fig.8 0. .15% reflectivity).6 1 POOR 0.4 0. 0.V INGEPET 2005 (EXPR-4-DU-14) 7 1. Migrated hydrocarbons in Tertiary cuttings. which is not completely understood to the present because of its poor outcrop characteristics. The main conclusions derived from this modeling (Figure 8) are: -The Ene Formation entered the oil window during the middle Eocene (35-40 my ago) and to the present time continues generating oil. This is a preliminary modeling and it needs to be adjusted according to the Tertiary tectono-stratigraphic evolution. Since there is not temperature data available within the basin it was necessary to utilize the heat flow calculated in the Camisea area (800 HFU). -The Cabanillas Group began to generate oil in the early Paleocene (65-60 my ago) and at the present time is mature enough to generate oil and some gas. and to the present time is generating mainly oil. .30 mm Fig. 7 . -The Ambo Group entered in the oil window between the late Paleocene to early Eocene (50 to 55 my ago). Indirect indication of the maximum burial depth is given by a fluid inclusion study from the Cushabatay reservoir at Paucartambo (37 my.V INGEPET 2005 (EXPR-4-DU-14) 8 Bitumen SHIRA Horizontal width = 0. Seismic Line 9 1D Generation Modeling In order to understand the petroleum system evolution history of the southern Ene basin it has been modeled using the Basin-Mod software. end of the Incaica Phase). 9 Vivian Vivian is a Campanian to Maastritchian gas and condensate reservoir. rippled quartzarenitic sandstone. with very small lateral variations in facies. Agua Caliente. This study is based on the information from 41 stratigraphic columns and from the analysis of 89 outcrop samples obtained from the Ene Basin by IPC. fine to coarse grained. proven in the Cashiriari field.8%. it can be as low as 6. The reservoir facies is 28 to 26 meters thick along the eastern flank of the basin (Pongo Paquitzapango. Lower Chonta. air permeability and density analysis (28 samples). Cushabatay. and thickening to 30 meters in the northern part of the basin (Oxapampa 19-1 well). were used as analogs.V INGEPET 2005 (EXPR-4-DU-14) 9 OIL WINDOW SHIRA Fig. radiometric dating (3 samples). Eurocan and Elf. 130 kilometers to the East of the Ene Basin (the Cashiriari-1 well production test had a maximum rate of 31 MM scfg/d and 743 BPD of 66.4° API condensate from sandstone with 15. and Nevati outcrops). massive to cross-bedded. fluid inclusions (2 samples). coarsening downwards. Vivian is locally eroded in some of the Andean structures currently outcropping. Vivian reservoir facies is composed of light brown. Tarobeni. .3% but close to the basin axis (Saoreni outcrop). thinning to 10 meters westwards (Pacchari anticline). whole sample x-ray diffraction’s (8 samples).Western Ene Basin Hydrocarbon Generation Model Reservoir The Ene Basin has Cretaceous and Paleozoic stratigraphic units capable of storing hydrocarbon fluids. The sandstone of the Vivian. Helium Porosity in the northern part of the Basin (Oxapampa 19-2 well) is up to 15. 8 .2% average porosity and 1 004 md permeability). Helium porosity. Mitu and Ene Formations should be considered as primary objectives. The analysis performed on the samples are: petrography (74 thin sections). Petrophysical parameters summary is shown in Figure 9. Core and drill stem test data from the Cashiriari and San Martin fields (Camisea area). 18 20 BASAL Ss 10 . The point count porosity in the Ene basin varies from 16.V INGEPET 2005 (EXPR-4-DU-14) 10 Permeability in the northern part of the basin spans from 40. 130 kilometers to the East of the Ene basin. medium grained cross bedded to laminated. Fm ENE BASIN CAMISEA Parameter ø (%) K (md) ø (%) K (md) VIVIAN 7 .16 3 . 130 kilometers to the East of the Ene Basin.23 14 . proven in the Cashiriari and San Martin fields.17 148 CUSHABATAY 10 . low angle cross stratified. 9 .13 23 . Lower Chonta reservoir facies is composed of gray. with calcite and pyrite cement.34 Fig. proven in the Cashiriari and San Martín fields. Rio Perene and Boca Satipo outcrops) or intercalated with green and red siltstone. well sorted. Agua Caliente reservoir facies is composed of white. Chonta reservoir thickness is 23 meters in the central part of the basin (Boca Satipo and Naranquiari outcrops).16 2 . (Cashiriari-1 well production test had a maximum rate of 30. is a gas and condensate reservoir of Cenomanian to Turonian age.16 480 JURASSIC SAND 23 ENE MAIN Ss (Noi) 10 1 .7 md (Oxapampa 19-2 well). The reservoir facies is intercalated .17 5 . coarsening upwards. to 0. locally rippled fluvial to coastal plain subarkosic quartzarenites.5° API condensate from sandstone with 16% average porosity and 148 md permeability). laminated or bioturbated.Ene Basin Reservoirs Characteristics Summary 9 Lower Chonta Lower Chonta is a gas and condensate reservoir of Turonian to Coniacian age. besides Chonta is absent locally by erosion or faulting related to Andean tectonics. The reservoir facies is intercalated either with gray shale in the middle part of the basin (Auti- Autiki.35 1 . with syn- depositional slumping towards the eastern flank of the basin (Chiriari-Rio Mazamari outcrop). with authigenic Kaolinite and Pyrite cement and occasionally with lithic fragments and mica grains.18 A.9 to 17% porosity and 41.2% in Paucartambo–Villa Rica.5 md permeability). but pinches out towards the north. (San Martín-3 well has 13.41 5 .8 MM scfg/d and 784 BPD of 64.21 1000 BASAL CHONTA 4 . 9 Agua Caliente It (known as Upper Nia in the southern Ucayali basin).15 3 . CALIENTE 15 . restricted marine beach sandstone. fine grained. 8% in Tarobeni- Tabesharo to 4% in Boca Satipo.78 at the basin axis (Saoreni outcrop). wave rippled.15 1 . medium grained. Permeability at the Chiriari-Mazamari outcrops is 0. Permeability at the Pongo Paquitzapango outcrop is 208 md. (Aguaytia –2 well produced 6. conglomerates and sandstone a long the western border (Rio Satipo section).V INGEPET 2005 (EXPR-4-DU-14) 11 with green shale in the western flank of the basin (Rio Tambo outcrop).48 MM scfg/d and 300 BPD of 63. Authigenic Illite. in the northeastern flank of the basin. whereas in the eastern flank (Pongo Paquitzapango outcrop) it is up to 22. At the Puente Paucartambo outcrop permeability ranges from 109 to 480 md. (San Martin-3 well has 0. currently producing at the Aguaytía field. A sample from this unit taken in the northern part of the basin. Pyrite. very few control points are available at present (Tabesharo and Pongo de Paquitzapango sections) and do not give a clear idea of the Cushabatay evolution. It is associated with a thick section of breccia. In the eastern flank of the basin (Rio Tambo outcrop) Cushabatay is only 50 meters thick. has hydrocarbon bearing fluid inclusions. The reservoir facies might be locally eroded in outcropping anticlines due to Andean tectonism. have 17% to 20% thin section porosity values and 5% to 22. 9 Mitu The sandstone facies tentatively correlated to the Mitu group (known as Lower Nia in the southern part of the Ucayali Basin) is considered to be a lateral equivalent of the gas and condensate reservoir of Permo- Triassic age (Rhaetian-Tatarian?). fluvial. indicating again the influence of fracture porosity. but 9. that has been proven in the Cashiriari and San Martin fields.14% porosity and 42. Reservoir facies thickness ranges from 30 meters in the northern part of the basin (Oxapampa 7-1 well). Cushabatay is up to 165 meters thick (Oxapampa 7-1 well). micaceous sandstone. tabular cross-bedded.4°API condensate from sandstone with 13. 450 to the North of Ene Basin. 9 Cushabatay It is a proven gas and condensate reservoir of Aptian to Albian age. Towards the East and the south. with local basal pebbly lags. Point count porosity is 1% in the Puente Paucartambo outcrop. 130 kilometers to the East of the Ene Basin.8 md. Local thickening is expected by faulting (In the Bella Esperanza outcrop the reservoir facies is 700 meters thick). located in the eastern flank of the basin have: 6% thin section porosity. subarkosic and sublitharenitic. The Boca Satipo outcrop. The Puente Paucartambo outcrops.9% Helium porosity values. . The reservoir facies is occasionally intercalated with brick red siltstone in the Northwestern part of the basin (Puente Paucartambo outcrop). located in the northern part of the basin. The Mitu Reservoir facies is composed of gray to red. Cushabatay porosity is influenced by its Feldspar and lithic fragments content and by its proximity to a fault zone.15 md. located in the central part of the basin.5 md permeability in the reservoir).5% Helium porosity due to fractures. Cushabatay is represented by braided fluvial sandstone in most of the sections. The point count porosity of the Agua Caliente reservoir facies in the central part of the basin (Boca Satipo outcrop) is 15% (Helium porosity is 14%). Up to 167 meters of this unit were measured in the northwestern part of the basin (Puente Paucartambo outcrop). and with yellowish gray siltstone in the northwestern part of the basin (Puente Paucartambo outcrop). Permeability in the central part of the basin (Boca Satipo outcrop) is 3 md. The Chiriari-Mazamari outcrops.3% porosity and 60 md permeability). has 7 to 3% porosity in thin section. and over 160 meters were encountered in the eastern flank of the basin (Chiriari-Mazamari outcrop). to 13 meters in the eastern flank (Rio Tambo outcrop). detrital clay and Quartz overgrowths partially occlude its pores. thinning westwards to 158 meters (Puente Paucartambo outcrop). in the northern part of the Ucayali Basin. at the Paucartambo-Villa Rica outcrop (sample MHX240). Thickness at the eastern flank of the basin ranges from 18 meters (Pongo Paquitzapango outcrop). The Rio Tambo outcrop has 8 to 19% point count porosity and 17.9% to 9. Pongo Paquitzapango outcrop. The reservoir thickness in the eastern flank of the basin (Pongo Paquitzapango outcrop) is 27 meters.6% in the eastern flank of the basin. Petroleum System The petroleum system in this basin could be defined and characterized by Paleozoic source rocks. Ene basal is a light yellow to light brownish gray. but the reservoir facies might be missing locally due to Triassic syn- rift erosion. fairly sorted. proven in the Cashiriari. Permeability at the Pongo Paquitzapango outcrop is 21. to 34 meters (Rio Tambo outcrop). (Cashiriari-1 well production test had a maximum rate of 22.7% Helium porosity.2% average porosity and 23 to 34 md permeability).5°API condensate from sandstones with 9. some detrital clay matrix. San Martin and Mipaya fields. coastal plain quartzarenite with quartz overgrowth cement. In the eastern part of the basin (Pongo Paquitzapango outcrop). Figure 10. The Pongo Paquitzapango outcrop sample has 9. minor amounts of Fe oxides. . 130 kilometers to the East of the Ene Basin. (San Martín-1 well production test had a maximum rate of 18 MM scfg/d and 690 BPD of 62. Porosity is dominantly intergranular. with traces of calcite. proven in the Cashiriari and San Martin fields.4% Helium porosity. sealed by interbedded shaly sequences and large. Cretaceous and Paleozoic reservoirs. faulted and thrusted anticlines as traps. permeability ranges from 0. quartz overgrowths. Porosity is dominated by grain dissolution processes. located in the southern part of the Ucayali basin. Pyrite and organic matter.8 Md. The Rio Tambo outcrop has 4.V INGEPET 2005 (EXPR-4-DU-14) 12 Ene o Main Sand Ene Main sand reservoir. Ene Main sand is a medium grained cross-bedded coastal plain quartzarenite cemented either by a dolomitic cement.3 md. ranging from 5. o Basal Sand Ene Basal sand reservoir is a gas and condensate reservoir of Lower Permian age.5 md. known as Noi in the Camisea area. Its pores are partially filled by authigenic Illite or Chlorite.4% average porosity and 20 md permeability). thickening eastwards towards the Ucayali Basin (Quebrada Anacayari outcrop) to 97 meters. trough cross bedded to laminated. Diagenetic events favour de development of secondary porosity in this unit.9 MM scfg/d and 601 BPD of 64. and minor amounts of Plagioclase or Feldspar grains. located 130 kilometers to the East of the Ene Basin.8°API condensate from sandstone with 8. fine grained feldspar rich.17 to 14. is a gas and condensate reservoir of lower Permian age. Agua Caliente and Vivian Formations with proved oil production in Oriente. the Lower Carboniferous Ambo Group (correlated with the gas and condensate fields from Camisea area) and the Devonian Cabanillas Group (related to some of the oils from Madre de Dios Basin). which has been drilled in the well Oxapampa 7-1 and has been correlated with the oils of the southern Marañon and northern Ucayali basins. The most conspicuous and regional seals are the Red Beds above the Vivian Formation. . the plastic shale of the Izcozacin Formation. The sequences with the best characteristics as reservoir are the Cretaceous Cushabatay. The traps are constituted by large thrusted and faulted anticlines. which are historically related to the Andean tectonics evolution. 10 . above the Cushabatay Formation and the shaly sequences interbedded with the reservoirs in the Mitu and Ene Formations.Ene Basin Petroleum System Elements As we mentioned before the Paleozoic formations with the best potential as source rocks are: the Permian Ene formation (related to some oils from Madre de Dios and Ucayali basins). the Quechua III tectonic phase is the responsible of the present structural configuration. The limestone and shale of the upper Chonta Formation. Marañon and Ucayali basins with and upside potential of the Permian Mitu and Ene sandstones which produce gas and condensate in the Camisea area. Additionally there is a possibility of the Triassic-Jurassic Pucara Group presence.V INGEPET 2005 (EXPR-4-DU-14) 13 DEV CAR PER TRIASSIC JURASSIC CRETACEOUS TER Q TIME M IS PEN E L E M L E M L EARLY LATE PAL NEO NEO APT ALB CEN TUR CON SAN CAM MAA EVENTS CAB AMB TAR COP ENE MITU PUCARA SAR CUSH ISC AC CHO VIV CA YAH ROCK UNIT SOURCE ROCK SEAL ROCK RESERVOIR ROCK OVERBURDEN ROCK TRAP FORM ATION GEN/MIGR/ACCUM PRESERVATION CRITICAL MOMENT Fig. Vol I. Marañon. • The prospective exploratory leads in the basin are large. 1996: Unpublished Reports • IPC. Huallaga. • The Ene basin is characterized by thin-skinned structural style. • This is a high risk-high potential exploratory area. • Probability of discovering new plays. 1966: Ene basin Geological Map • SHELL. • EUROCAN VENTURES. 1993: Technical Evaluation Agreement Final Geological Report • ELF PETROLEUM PERU: 1999: Block 66 Final Report. . 1966: Field Note books 765. Agua Caliente and Cushabatay Formations. • The potential Paleozoic reservoirs are The Mitu Group and the Ene Formation. • There is an active petroleum system in the basin tested by the presence of migrated hydrocarbons. • The potential source rocks are the Permian Ene formation. 1996: Regional Geochemical Study of oils and source rocks in the Santiago.V INGEPET 2005 (EXPR-4-DU-14) 14 Conclusions • In the Ene basin are present sediments ranging in age from Ordovician to Quaternary. Ucayali and Madre de Dios basins.II. the Lower Carboniferous Ambo Group and the Devonian Cabanillas Group. Technical and Economical Contributions • Evaluation of the frontier area. 1992: Onshore Peru. Ene. Lower Chonta. hydrocarbon Potential and Prospect Analysis. 1996: Geological Fieldwork Report. References • CORE LAB. Ucayali Basin • SHELL: Unpublished Geochemical Reports • SIMON PETROLEUM TECHNOLOGY. • Probability of findings new hydrocarbon reserves. 1987: Final Report Blocks 38-42 • SHELL. 753 and 754 • IPC. 1993: Geology. Ucayali Basin. thrusted and faulted anticlines. 1995: Camisea Feasibility Study • SHELL. Ene basin Technical Review • EUROCAN VENTURES.III • ELF AQUITAINE PRODUCTION. • The potential Cretaceous reservoirs are: Vivian.