Drainage Anomalies in Gulf Coast Tertiary Sandstones: ABSTRACT

Abstract

Unanticipated drainage patterns or drainage anomalies are common phenomena in Gulf Coast Tertiary sandstones. Drainage anomalies can occur in reservoirs that were deposited in a single depositional environment or in several environments. They can be recognized by an analysis of the production data, from pulsed neutron logs, or from logs in new wells drilled later in the life of the field. One of the best ways to locate drainage anomalies is by undertaking comprehensive subsurface engineering reviews which incorporate all geologic, petrophysical, production, and reservoir engineering data from the field--the synergistic End_Page 463------------------------------ approach. Recognition of these drainage anomalies often leads to the drilling of new wells or the recompletion of existing wells, thereby increasing the ultimate recovery from a reservoir. Five examples of drainage anomalies in three offshore Louisiana fields include two from South Pass Block 27 field; one from South Pass Block 24 field; and two from Eugene Island Block 18 field. Three are from reservoirs which were deposited in several depositional environments and two are from single environment reservoirs. Four are oil reservoirs and one is a gas reservoir. End_of_Article - Last_Page 464------------