DUVAL, BERNARD, and CARLOS CRAMEZ, Total, Paris, France, JOSE FIGUERA, Maraven, Caracas, Venezuela, RAFAEL LANDER, Corpoven, Puerto La Cruz, Venezuela, and GUSTAVO HERNANDEZ, Lagoven, Caracas, Venezuela

ABSTRACT: Giant Fields of the Late 80s Associated with Type "A" Subduction in South America

About 10 billion bbl of recoverable oil have been found in these three fields for which the petroleum generating subsystem is very similar. The potential source rocks are the organic sediments associated with the major downlap surface of the post-Pangea continental encroachment sedimentary cycle, i.e., MFS 91,5 Ma (La Luna formation). However, the concentrating physico-chemical petroleum subsystem is quite different. The El Furrial/Musipan field is associated with a Tertiary foredeep basin overlying a generating Atlantic type passive margin. On the other hand, Cusiana and Ceuta fields are associated with a Tertiary foredeep basin developed over a generating back-arc basin. The different stacking of sedimentary basins controls the migration/entrapment petroleum subsystem. In El Furrial Musipan, dEcollement surfaces and their associated thrusts are predominant whereas, in Ceuta and Cusiana the majority of compressional structures are created by tectonic inversions. These tectonic settings create different petroleum systems: (a) supercharged with low impedance and lateral drainage in El Furrial/Musipan, (b) normally charged with high impedance and vertically drained in Ceuta and Cusiana area. Each case requires appropriated exploration approaches.

AAPG Search and Discovery Article #90988©1993 AAPG/SVG International Congress and Exhibition, Caracas, Venezuela, March 14-17, 1993.