Published 1995 as part of Memoir 62
Copyright © 1995 The American Association of Petroleum Geologists.   All Rights Reserved.

The purpose of this two-dimensional computer simulation of basin evolution, based on geologic, geophysical, geochemical, geothermal, and hydrodynamic data, was to determine the hydrocarbon generation and migration history of the basin. The modeling covered two geologic sections (platform and prethrusting) located along the Chacopata-Uverito transect in the Eastern Venezuela basin. In the platform section, a hypothetical source rock equivalent to the Guayuta Group was used to simulate the migration of hydrocarbons. The thermal history reconstruction of the hypothetical source rock confirms that it would not have reached the oil window before the middle Miocene and that the maturity in this sector is due to the sedimentation of the Freites, La Pica, and Mesa-Las Piedras formations. The expulsion of the hydrocarbons took place mainly into the Oligocene-Miocene reservoir and has not yet reached zones located beyond the Oritupano field. This implies that the oil in the southern part of the basin was generated by a source rock located to the north, in the actual deformation zone. For the past 17 m.y., water has migrated from north to south in this section. In the prethrusting section, the hydrocarbon expulsion started during the early Tertiary and migrated mainly into Lower Cretaceous reservoirs (El Cantil and Barranquín formations). At the end of the passive margin stage, hydrocarbons migrated across the Merecure reservoir zone and into the Onado area before thrusting began.