Un modelo 3D de la densidad del subsuelo en el graben de Espino: un aulacógeno Jurásico en el oriente de Venezuela

Abstract

As a part of a program to generate opportunities for oil exploration in eastern Venezuela, we have obtained a 3D subsurface density model over the Espino graben region, by the linear inversion of isostatic residual Bouguer gravity anomalies. The obtained model suggests that the sedimentary column is at least 6500 m thick in the central portion of the graben. We interpreted the model zero density contrast surface as the economic basement, and on that surface we observe an upward concave region with north and south edges inclined consistently with the border faults of the graben. It is interpreted that within the concave region, where the density contrast is negative, the graben accommodates some 3500-m thick sedimentary sequences that were deposited during an episode of crustal extension in Jurassic times. The shallow portion of the model suggests 3000-m thick, sub horizontal strata, interpreted as sedimentary sequences deposited after the episode of crustal extension.