Green River Formation Water Flood Demonstration Project: Final report. [October 21, 1992-April, 30, 1996

Abstract

The objectives were to understand the oil production mechanisms in the Monument Butte unit via reservoir characterization and reservoir simulations and to transfer the water flooding technology to similar units in the vicinity, particularly the Travis and the Boundary units. Comprehensive reservoir characterization and reservoir simulations of the Monument Butte, Travis and Boundary units were presented in the two published project yearly reports. The primary and the secondary production from the Monument Butte unit were typical of oil production from an undersaturated oil reservoir close to its bubble point. The water flood in the smaller Travis unit appeared affected by natural and possibly by large interconnecting hydraulic fractures. Water flooding the boundary unit was considered more complicated due to the presence of an oil water contact in one of the wells. The reservoir characterization activity in the project basically consisted of extraction and analysis of a full diameter c ore, Formation Micro Imaging logs from several wells and Magnetic Resonance Imaging logs from two wells. In addition, several side-wall cores were drilled and analyzed, oil samples from a number of wells were physically and chemically characterized (using gas chromatography), oil-water relative permeabilities were measured and pour points and cloud points of a few oil samples were determined. The reservoir modeling activity comprised of reservoir simulation of all the three units at different scales and near well-bore modeling of the wax precipitation effects. The reservoir characterization efforts identified new reservoirs in the Travis and the Boundary units. The reservoir simulation activities established the extent of pressurization of the sections of the reservoirs in the immediate vicinity of the Monument Butte unit. This resulted in a major expansion of the unit and the production from this expanded unit increased from about 300 barrels per day to about 2000 barrels per day.