Print this pageReservoir Characterization and Improved Water-Flood Performance in Glenn Pool Field: A DOE Class I Project
KERR, DENNIS R., LIANGMIAO YE, MOHAN KELKAR and BAHAR ASNUL
Study of the Glenn Sand (Middle Pennsylvanian) in Glenn Pool field northeastern Oklahoma has been a joint partnership between the U.S. Department of Energy, The University of Tulsa, Uplands Resources (operator) and Amoco Production Company. The project goal is to improve water-flood performance in this 90-year-old field through detailed reservoir characterization using conventional and advanced technologies. To date, efforts have focused on a 160-acre tract including about 1-year of implementation of a new reservoir management plan.
Four architectural levels are recognized in the reservoirs that make up the Glenn Sand. (1) Largest scale (rock volume) is multistory discrete genetic intervals (DGI) that comprise the 150 ft thick interval and are traceable across the southern extent of field. (2) Seven DGIs are recognized descending from A through G. Sandstones of each DGI are vertically separated by generally continuous mudstones except for localized areas of erosion. (3) Each discrete genetic interval is composed of facies: braided fluvial (confined to DGI F and G); meandering fluvial channel-fill and crevasse splay (DGI A to D); and overbank mudstones. (4) Channel-fill facies is divided into subfacies: a lower subfacies comprising trough cross-stratified, medium-grained sandstones; a middle subfacies dominated by mudstone draped epsilon cross-stratified, fine-grained sandstone; an upper subfacies composed of mudstone.
From core and borehole-image log analysis it is dear that much of the remaining resource (up to 80% of OOIP) is located in the middle channel-fill subfacies and in crevasse splay complexes. Several management scenarios were evaluated using different reservoir simulations and well configurations. The most economically reasonable for this part of Glenn Pool field involved a reconfiguration of perforations in producers and injectors of existing vertical wells. With only half of the plan in effect to date, increased production is 200% above our projections.