Improved treatment of acrylamide co- and terpolymers for water control in gas-producing and storage wells

The main objective of this study was to determine the optimal conditions for application of acrylamide co- and terpolymers for water control in gas wells under various environmental conditions. Starting in February 1992, the limits of application of acrylamide co- and terpolymers were first defined in the laboratory through extensive tests. Based on the results of the comparative feasibility study, four field tests were performed in both gas reservoir and underground gas storage wells. This paper presents the latest results of field tests. Using a partially sulfonated acrylamide terpolymer, the first field test was performed in January 1993 on an abandoned gas-producing well with a BHT of about 130°C, an average matrix permeability of 0.01 μm2 and a produced brine salinity of more than 300 g/l TDS. The second test was performed in a well from a gas storage field with a temperature of about 87°C, an average permeability of 0.06 μm2 and a produced brine salinity of more than 270 g/l. Based on the information provided from the first field test and the feasibility study performed for this well, a lower molecular weight partially sulfonated acrylamide terpolymer was finally used for this test. Using a cationic acrylamide copolymer, the third field test was performed in a low-temperature, high-brine-salinity gas storage well with BHT of 30°C and brine salinity of 218 g/l. Based on the excellent results of the third field test, the same polymer was selected for the last water shut-off treatment in a low-temperature gas storage well with a matrix permeability ranging from 0.04 to 3.6 μm2. Since the treatment, the gas well and the gas storage wells have exhibited improved production performances.