for hydrocarbons

OPEN ROUND COLOMBIA 2010 URABA AREA January, 2010

Total Hectares Seismic LinesWells TotalKmTotal Urabá Area Urabá Blocks Basin data BLOCKS AREA (Ha) URA URA

Regional Tectonic Framework X Necocli-1 Apartado-1 Chigorodo-1

Apartado -1 WellChigorodo -1 Well AGENCIA NACIONAL DE HIDROCARBUROS Overview Urabá Basin

General Surface Geology Faults and structural lineaments by accumulated number rose diagram Uraba Basin suggested geologic column. Modified from Fllinch (in Bertolini et al, 2003) based on the description provided by ECOPETROL, 1982a. Necoclí -1 Apartadó -1 Chigorodó-1

Reservoir Rock Source Rock Seal Rock Petroleum Geology Stratigraphic Columns Apartadó-1 Well Chigorodó-1 Well

Wells and Seismic Lines Uraba Basin Necoclí -1 Apartadó -1 Chigorodó -1 LEGEND Wells ___ Seismic line Urabá-1 Turbo X

Bouguer Anomaly Map LEGEND ___ Contour Interval (20 mGal)

Seismic line Representative Seismic Urabá Basin

Seismic line Representative Seismic Urabá Basin

Representative Seismic Urabá Basin Seismic line 13-5

Seismic Structural Interpretation

Organic Geochemistry Necoclí -1 Well MIOCENE Source Rock Quality Thermal Maturity

Prospectivity The wells drilled allow identifying several sandstone intervals in the sedimentary sequence, which could be reservoirs. The claystones interbedded in the sequence could act as local/regional seals. Normal faults create structural- stratigraphic traps by onlap/juxtaposition against the basement, and to the W-SW stratigraphic traps by onlapping on the basement. In the eastern margin of the basin the development of compressional folds close to the Uramita Fault are observed.

The geochemical information (Necocli-1 well) is insufficient to corroborate or rule out the existence of proper conditions for hydrocarbons generation in the basin. It is also not possible to characterize any of the informal stratigraphic units as potential source rock. Regarding the reservoirs, the wells information shows the deposit of sandstones interbedded with claystones and siltstones along all the drilled sequence in the Apartado-1 and Chigorodo-1 wells. This implies that practically all the units in the basin could be potential reservoirs. Regarding the plays in the area, the seismic information indicates that the basin is tilted to the northeast and has flexural geometry. This flexure causes the development of normal faults that generate structural highs against which the sediments in the basin are truncated/onlapped, especially the deepest units (Units C and D). Due to the progressive basement’s shallowing towards the southwest; the more recent sediments overlap or pinch out against the basement in that direction creating potential stratigraphic traps. Conclusions

Germán Vargas Cuervo Msc - Ph. D. Project Manager Luis Castillo lópez Msc - Ph. D. Roberto Aguilera Consultant Geologist Diana M. Jiménez ANH Supervisor Universidad Nacional de Colombia Work Team