Mike Coward¹, Alison Ries¹

(1) Ries-Coward Associates Limited, Reading, United Kingdom

ABSTRACT: Petroleum Systems in the Compressional/Transpressional Margin of Eastern Venezuela and Trinidad

This paper aims to examine new and alternative models for the oilfields immediately S of the Serrania Orientale in Eastern Venezuela and in the adjacent parts of the Gulf of Paria and western Trinidad. The structures have been previously interpreted in terms of thin-skinned tectonics, where the thrusts are linked to a basal detachment, usually within the cover sequence. However faults and folds related to Oligo-Miocene thick-skinned, basement-involved, deformation have been recognised along the El-Furial - Viboral trend in Venezuela and along the later Miocene Pedernales - SW Trinidad trend. These thick-skinned structures are associated with transpression along the Venezuelan-Caribbean plate margin. Thin-skinned structures occur, but they hide thrust geometries and associated sub-thrust hydrocarbon plays related to basin inversion at depth. The thick-skinned structures rework basin bounding faults, originally parts of a complex pull-apart system, that controlled source and reservoir distribution. They generally initiate before adjacent thin-skinned thrusts, blocking hydrocarbon migration across the foreland basin. The Pedernales - SW Trinidad play involves soft-linked compression of an original soft-linked extensional basin. Recognition and mapping of these structures therefore is critical for modelling hydrocarbon maturation and migration within a basin.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado