Multiphase Tectonic Evolution of Northwestern Venezuela and Its Offshore Area: Implications for the Distribution of Source and Reservoir Rocks

Alejandro Escalona¹, Paul Mann¹, and David Gorney^2
1 Jackson School of Geosciences, The University of Texas at Austin, Austin, TX
² ExxonMobil, Houston, TX

Integration of seismic data with existing onland geologic data from the Leeward Antilles, Bonaire basin, Falcon basin, Gulf of Venezuela, Paraguana Peninsula, and Maracaibo basin reveal five regional tectonic phases that place fundamental constraints on the distribution of hydrocarbons. The five events include: 1) Late Paleocene-middle Eocene southeastward thrusting of the Lara nappes in the area east of the Maracaibo Basin; the right-lateral Burro Negro tear fault reactivated the preexisting Paleocene-early Eocene Maracaibo paleoshelf edge; rocks west of the fault zone are hydrocarbon-rich, those to the east are hydrocarbon-poor; 2) Late Eocene– early Oligocene extension of the 3 to 6-km-thick Falcón-Bonaire basin along east-west striking normal faults now inverted by later shortening; western Falcon basin overlies hydrocarbon-rich passive margin rocks and continental crust, similar to those of the Maracaibo Basin; central and eastern Falcon basin overlies hydrocarbon-poor rocks and metamorphosed Caribbean arc crust; 3) Oligocene-early Miocene northwest-striking normal faults extended hydrocarbon-poor Caribbean crust of the Leeward Antilles and formed deep, submarine deep water channels; 4) Middle Miocene-Pliocene inversion of the Falcón basin; this inversion phase is reflected in the present-day pattern of east-northeast-trending, hydrocarbon-poor fold-thrust belt that can be traced over 200 km along the eastern coast of the Falcón basin; and 5) ~80 km of Oligocene to Recent right-lateral strike-slip along the Oca fault. Restoration of right-lateral displacement on the Oca fault places hydrocarbon-rich rocks of the continental margin in the SW and central parts of the Gulf of Venezuela and hydrocarbon-poor rocks in the E and NE parts.