Enhanced oil recovery by improved waterflooding. Fourth annual report, October 1980-September 1981. [Illinois]

Energy Resourcs Co. Inc., and its subcontractor Elf Aquitaine Oil and Gas Company are conducting a 100-acre pilot polymer flood in the Storms Pool Field near Carmi, in White County, Illinois. The project is a cost-sharing venture with the United States Department of Energy (DOE). Preparation for the polymer flood began in September 1977, and the project is scheduled for completion in December 1983. This report reviews progress during the fourth year of performance (October 1980 through September 1981). The Storms Pool, once highly productive, has yielded over 12 million barrels of oil from the Waltersburg formation since its discovery in 1939. The field has been waterflooded for over 20 years and is now largely in stripper production with high watercuts at most producing wells. Material balance and recent electric logs indicate, however, that there is a substantial volume of movable oil still in place, presumably bypassed by the inefficient waterflood. The polymer flood is intended to improve the sweep efficiency, showing that the engineering, management, and financial resources required for such tertiary techniques can be applied to similar fields that might otherwise be abandoned for lack of investment by parties knowledgeable in enhanced oil technology. Preflush injection and polymer injection were both initiated during this period with total polymer injection now standing at 179,453 barrels (or about 6% pore volume). Laboratory testing has continued throughout the year with the emphasis being on field support (troubleshooting field problems and monitoring the field injection and production systems). No evidence of polymer break-through has been detected at the production wells. Details of the interference testing program and the radiotracer study executed during this period are also presented