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Abstract: Sedimentological and Stratigraphic Controls on Hydrocarbon Accumulation and Production, Pauji Formation, Maracaibo Lake, Venezuela

Manuel Delgado, Fernando Chacartegui

The Middle to Late Eocene Pauji Formation present in the Maracaibo Basin constitutes a major trangressive, second order cycle event that covered and affected most of the Maracaibo Basin.

It is mainly composed of grey to dark grey, massive, marine shales; however, in the Motatan Field, which is located onshore, in the southeast corner of the Maracaibo Basin, it develops a lower sandy and prospective interval.

These lower sandstone units represent a third order cycle, spanning from 44.5 m.y. to 45.5 m.y. They consist of two northerly aggrading to prograding stacked parasequence sets of a highstand systems tract deposited in a nearshore to platform setting. Each parasequence set consists of three individual coarsening upward, geographically extensive parasequences composed of several stacked nearshore bars. These nearshore deposits consist of four sandy lithofacies, two heterolithic ones and a shaly one. Most of these facies are highly bioturbated, shaly and highly cemented; nevertheless, a medium grained (facies S3) and a coarse grained (facies S) lithofacies, located at the top of the nearshore bar deposits, are porous and hydrocarbon bearing. Production and storage capacity is mainly prov ded by these prospective lithofacies; meanwhile, production rates are significantly enhanced in certain areas of the field by open fractures generated by regional tectonic events.

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