MARCANO, FERNANDO, and SIMON PADRON, Maraven S.A., Caracas, Venezuela

ABSTRACT: Thermal Modeling in Ceuta, Maracaibo Basin, Venezuela

Hydrocarbon generation from Upper Cretaceous source rocks (Fm. La Luna) in Ceuta, center-eastern Maracaibo lake area in Venezuela, is modeled here, using a kinetic method and the conventional Time-Temperature Index (TTI) procedure.

Geological evolution, burial and erosional history is based on available interpretation of 3-D seismic and well data. Fragmentary present-day subsurface temperature data comes from corrected measurements in a few wells. Paleogradient/heat paleoflux was estimated during the thermal modeling on wells, by calculating vitrinite reflectances (Ro) or Tmax values and then comparing them with measured ones. However, thermal-indicator data does not always appear to be consistent and some data had to be rejected. Paleogradient evolution in the Cretaceous is controlled by the development of an isolated thermal compartment related to overpressures in a thick shaly sequence in the Upper Cretaceous.

A geological section was studied in detail to illustrate possible migration paths to known fields and undrilled traps. Results show a good fit between the thermal evolution of the source rock and the maturity of the crude produced in the area.

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