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Abstract: Hydrocarbon Generation and Migration Modeling, Eastern Venezuela Basin

N. Chigne, F. Russomanno, H. Sanchez, A. Callejon, A. Finno, N. Escalona

The Eastern Venezuela basin, with an area of approximately 180,000 km2 contains important giant oil fields as well as large unexplored areas.

In this region has been identified clearly all the elements of a huge Petroleum System which was kinematically modeled in time and space, following the basin Modeling method.

A passive margin originated during the Cretaceous and early Tertiary epochs, followed by emplacement of allochthonous thrust sheets coming from the west and development of a foreland basin. Therefore, thrusting basin formation and structures are progressively younger (Oligocene to Middle Miocene) from west to east.

Heat flow has increased during the Tertiary to Recent epochs from 40 to 100 mW/m2, only in the north-central part of the basin, as interpreted from present maturity data.

The first stage of oil generation occurred during late Eocene and Early Oligocene in the northernmost part of the basin. Most of oil migrated more than 150 km southernward up the undeformed homocline of the passive margin. Thus forming the Orinoco Oil Belt.

Younger kitchens were later formed from north to south during Early Miocene to Recent. Oils from these kitchens were trapped by increasing tectonic deformation before reaching the southern border of the basin. Light and medium gravity oil fields were discovered in this tectonically complex area.

This study has helped assess the hydrocarbon potential of as yet unexplored areas, by taking into account important quantitative factors previously not considered.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France