AGUADO, B., Intevep S.A., Caracas, Venezuela, L. RAMIREZ, Lagoven S.A., Monagas, Venezuela, and M. QUINTERO, Intevep S.A., Caracas, Venezuela

ABSTRACT: Sedimentology of the Boquerun Field, Eastern Venezuelan Basin

The Boquerun Field, located in the Carito-El Furrial-Boquerun Trend, a giant field in the Eastern Venezuelan Basin, contains an oil saturated section that comprises both Cretaceous and Tertiary strata. The description of 1300 ft of core allowed the definition of 15 lithofacies including sandy, shaly, carbonatic and even glauconitic rock types. The association of those lithofacies together with palinological and micropaleontological data, derives in the determination of nearshore, inner to outer platform and slope environments of deposition. The sequence is a good example of a perfect major transgressive cycle as shown by the transition from nearshore bars to a turbidite assemblage, through a carbonate-glauconite platform.

The producing interval is restricted to nearshore marine sandstone bars and turbiditic channels, since the limestones are tight. The bars are subarkosic to sublitharenitic in composition, and are very strongly cemented by quartz. Clay mineralogy is formed by mixed-layer illite/smectite, and chlorite. Porosity is due to microcline and orthoclase dissolution. The turbiditic channels are quartzarenitic and most porosity is relict primary, with a contribution from carbonate and glauconite dissolution. Clay mineralogy is composed of kaolinite and chlorite.

Even though this field has a high potential of production, it has been dampened by sand plugging that could be related to the environments of deposition and/or the diagenetical evolution of the rocks. Further tests have to be made in order to restrict the sand producing interval.

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