Controlling Water Production Using Gelled Polymer Systems

Abstract

Summary: Arbuckle reservoirs in central Kansas produce by natural water-drive. Although clean oil is usually produced on initial completion of a well, the water cut increases with time. Water cuts of 99% and water production rates of 400 to 3,000 B/D are common. Wells cannot be pumped off. Water production has been reduced selectively by treating wells with a chrome acetate-polyacrylamide gelant. In most cases, incremental oil is produced following the treatment. This paper describes results from a seven-well program in which production wells were treated with chrome acetate-polyacrylamide gelant. Pressure data were obtained before the treatment, during the gel treatment and after gel treatment. Buildup data were interpreted to estimate kh before the treatment, and the extent of permeability reduction to oil and water caused by the treatment. Bottomhole-pressure (BHP) data obtained during the treatment provided were used to monitor gelant placement. Production data following the treatments were analyzed to determine incremental oil production and correlate the treatments to the production response. Water-production rates were reduced in every well, and reductions were persistent during intervals ranging from 7 to 36 months. Incremental oil was produced in four of seven wells treated in the program. The amount of incremental oil increased with volume of gelant injected in wells with openhole completions. Results of this test program suggest how to distinguish wells that are likely to take large treatments from those that can be treated only with small amounts of gelant. These results should improve treatment design and identify wells that are good candidates for successful treatment.