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DRONKERT, HANS, Delft University of Technology, The Netherlands, and THEO E. WONG, Geological Survey of The Netherlands, Haarlem, Netherlands

ABSTRACT: Geology of the Tambaredjo Oil Field, Suriname

After the initial discovery in the sixties of oil below the coastal plain of Suriname (S. America), the State Oil Company of Suriname started production of the unique Tambaredjo field in 1982. The heavy, biodegraded oil (14 to 16 degrees API) is produced under compaction drive, from the Paleocene T-sand (average thickness 5 m) at a depth of about 300 m. More than 300 wells have been drilled in an area of about 200 sq km. High resolution seismics makes it possible to correlate units down to 2 m thick. This dense network of bore holes is very suitable for geological correlations and 3D modeling.

The T-sand reservoir consists of angular, medium to coarse grained unconsolidated sands with interfingering clays and lignites. The sands are deposited on a well cemented erosional Cretaceous basement. The reservoir is sealed by locally continuous clays. The oil is trapped in structural highs created by syn-sedimentary rejuvenated basement faults.

The depositional environment of the T-sand ranges from fluviatile to deltaic. Frequent avulsion and synsedimentary faulting created a highly compartmented reservoir. Although interconnectedness of the sand bodies is high, clay smears and silting out of the edges confine reservoir compartments. The best genetic sand units such as channel fills or mouth bar deposits hardly correlate over more than a few hundred meters.

The Tambaredjo oil field offers an unique opportunity to study the detailed sedimentology and petroleum geology of a fluvio-deltaic transitional realm on the passive margin along the Guiana coast.

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