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Adolfo Portilla1
(1) Petróleos de Venezuela, Exploración-Producción, 829/2074 Caracus, Venezuela

Abstract: The Arauca, Mérida and El Baúl Arches in the Barinas-Apure Basin, Western Venezuela: New evidences related to their existence and importance in hydrocarbon exploration

The Barinas-Apure basin has been intensely explored, both geophysically and geologically, leading to the interpretation and definition of regional structures such as the Arauca, Mérida and El Baúl Arches. Nevertheless, skepticism, confusion and controversy with respect to the actual existence of these arches, their age, orientation, extension, and importance in hydrocarbon exploration, still prevail among scholars. Revision and analysis of previous interpretations lead to the following conclusions: 1) The existence of the Arauca Arch in the Apure area is not evident, if it exists, it should be a structural nose plunging N25W, of Cretaceous-Paleocene age, with the Guafita and Caño Limón oil fields located on its southern flank; it should be the northern extension of the arch located in Los Llanos Colombianos basin, that has not been reported yet. The arch was established aligning structures whose major axes are perpendicular to the arch axis. 2) The Mérida Arch, in the Mérida Andes, is of Precretaceous age, while the heavily faulted structural high present in the Paez-Mingo-San Silvestre area, of N-S orientation, is of Cretaceous-Paleocene age, what makes these structural elements genetically different. This high is responsible for the large hydrocarbon accumulation in the traditional oil fields of the Barinas basin. 3) The El Baúl Arch, oriented N75W, and formed during the Cretaceous-Paleocene tectonic event, constitutes the most important structure in the subandean Venezuelan basins that controlled sedimentation in the eastern Barinas basin and to the west of the Eastern Venezuela basin, from Oligocene to Pleistocene.

AAPG Search and Discovery Article #90914©2000 AAPG Annual Convention, New Orleans, Louisiana