This report summarizes data produced as part of a U.S. Department of Energy (DOE) project to evaluate methods for improving waterflood response in the Upper Cretaceous D sandstone of the Denver basin. Historically poor performance of waterflooding in this widespread reservoir has meant total recoveries averaging less than 20% of original oil in place (OOIP), with considerable variation in local sweep efficiency. Detailed reservoir characterization of the D sandstone in the Sooner unit, integrating well-log, core, seismic, and engineering data, resulted in an updated reservoir model that included delineation of multiple reservoir compartments. This model was used as a basis for a field redevelopment plan whose initial stage involved realigning existing injectors/producers and drilling several infill locations to increase sweep efficiency on a compartment-by-compartment basis. Results of implementation included a 100% increase in daily unit production, an increase in proven reserves of 696,000 bbl oil equivalent to more than 10% of OOIP. On the basis of these results, ultimate recovery from the unit, with implementation of selective infill drilling, is projected at 32.6% OOIP. Success of the project

© Copyright 1997. The American Association of Petroleum Geologists. All rights reserved.

¹Petroleum Consultant, 1511 18th Avenue East, Seattle, Washington 98112.

Grateful acknowledgment is expressed to Mark Sippel of Mark Sippel Engineering (Denver, Colorado) for providing data and expertise essential to the writing of this report. Appreciation is also extended to Floyd Bardsley for artwork.

Send reprint requests to AAPG Publications Manager, P.O. Box 979, Tulsa, Oklahoma 74101-0979.

M = million, G = billion.