 |
Abstract
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. |
|---|
