Determination of Swelling Behavior and Mechanical and Thermal Resistance of Acrylamide-Acrylic Acid Copolymers under High Pressures and Temperatures.

Unwanted water production is a serious problem accompanying oil extraction especially in oil-fractured reservoirs. An effective approach to tackle this issue is to utilize gels as a blockage agent. In this paper, an effective series of preformed particle gels (PPGs) was synthesized by a free radical copolymerization of acrylamide and acrylic acid [poly(AAm--AA)] copolymers. The key factors of synthesis experiments, gelation time, drying behavior, swelling capacity (in CaCl·2HO, MgCl·6HO, BaCl·2HO, KCl, NaCl, and LiCl saline solutions with 200,000 ppm concentration and pH from 3 to 8), and mechanical and thermal resistance of the synthesized PPGs (with a homemade apparatus) were elucidated. Laboratory results revealed that the prepared PPG sample 1 (9.65 mole ratio of AAm/AA and 6 mol % of MBA) would be a good candidate for controlling water in oil and gas reservoirs with a salinity, pressure, and temperature of up to 200,000 ppm, 300 bar, and 170 °C, respectively, and pH values ranging from 3 up to 8.