ROJAS, B.,* A. SALAZAR,* A. ROBINSON, M. MEUNIER, P. OVIEDO,* J. SWALLOW, and L. DIAMOND, Corpoven, S.A., Puerto La Cruz, Venezuela

ABSTRACT: A Multidisciplinary study of the complex Santa Barbara-Furrial Oilfields, Northern Monagas Area, Eastern Venezuela Basin

A multidisciplinary study has been conducted on the giant oilfields located in the northern Monagas area of the eastern Venezuela basin. The oilfields occur in a lower tertiary and Cretaceous sequence which has been heavily tectonized as a consequence of recent transpression along the Caribbean - south American plate boundary.

This structurally complex area was initially mapped by using 3000 km. Of 2d seismic data. Experience has shown these data to be inadequate and a 150 sq. Km 3d survey was acquired over the Santa Barbara area. These data have been interpreted and several new structural features have been identified. As a consequence of this work the structural model has been modified and applied throughout the area.

The Cretaceous to late Oligocene sediments, including the Naricual formation which is the main producing horizon, has been studied systematically. These sediments were deposited initially in a fluvial environment which was gradually inundated by successive marine incursions.

Approximately 7000 ft of core has been logged and the sedimentary facies and sequence boundaries recognized were then used to calibrate electric logs which allowed facies extrapolation across the whole area. The final parasequence analysis has provided a detailed and reliable reservoir correlation.

Original pressure data and subsequent production histories, together with different known oil-water contacts implies separate producing areas. Complex fluid segregations, from condensates to heavy oil had also to be explained.

The integration of the geophysical, geological, fluid and production data has allowed each discipline to refine their field models by removing conflicts between these data, thereby producing a better overall description of the reservoir.

AAPG Search and Discovery Article #90988©1993 AAPG/SVG International Congress and Exhibition, Caracas, Venezuela, March 14-17, 1993.