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Abstract: Comparison of the Petroleum Systems of East Venezuela in Their Tectonostratigraphic Context

Nicholas J. Stronach, Helen M. Kerr, John Scotchmer, Vernon Hunter

The Maturin and Guarico subbasins of East Venezuela record the transition from Cretaceous passive margin to Tertiary foreland basin with local post-orogenic transtensional basins. Petroleum is reservoired in several units ranging from Albian (El Cantil Formation) to Pliocene (Las Piedras Formation) age. Source rocks are principally in the Upper Cretaceous (Querecual Formation), and Miocene (Carapita Formation) in the Maturin subbasin and in the Upper Cretaceous (Tigre Formation) and Oligocene (Roblecito and La Pascua Formations) in the Guarico subbasin.

An extensive well database has been used to address the distribution and provenance of hydrocarbons in the context of a tectonostratigraphic model for the evolution of the East Venezuela basin. Nine major plays have been described, comprising thirteen petroleum systems.

The principal factors influencing the components of individual petroleum systems are as follows:

1. structural controls on Upper Cretaceous source rock distribution, relating to block faulting on the proto-Caribbean passive margin;

2. paleoenvironmental controls on source rock development within the Oligocene-Miocene foreland basin; and

3. timing of subsidence and maturation within the Oligocene-Upper Miocene foreland basin and the configuration of the associated fold and thrust belt, influencing long range and local migration routes

4. local development of Pliocene post-orogenic transtensional basins, influencing hydrocarbon generation, migration and remigration north of the Pirital High.

AAPG Search and Discovery Article #90951©1996 AAPG International Conference and Exhibition, Caracas, Venezuela