Self-assembled acrylamide-based copolymer/surfactant with high-temperature resistance for enhanced oil recovery

In this article, we report on a water-soluble self-assembled system that consisted of an acrylamide (AM)-based copolymer and a nonionic surfactant for enhancing oil recovery. The copolymer, denoted as poly(acrylamide-acrylic acid-diallyl dimethyl ammonium chloride-N-allyl benzamide) (PMADN), was synthesized with AM, acrylic acid, diallyl dimethyl ammonium chloride, and N-allyl benzamide, and the nonionic surfactant was Tween 40. The results of our investigation of the ratio of the copolymer to Tween 40 show that the optimal concentrations of PMADN and Tween 40 were 1000 and 500 mg/L, respectively. When it was heated to 115-120 degrees C for 15 min, the apparent viscosity of the self-assembly system increased 19.2%, and its viscosity retention rate remained at 11.6% under 1000 s(-1). When the system was dissolved in 12,000 mg/L NaCl, 2000 mg/L CaCl2, and 2000 mg/L MgCl2 solutions, the viscosity retention rates were 22.3%, 12.1%, and 17.6%, respectively. In addition, a 2000 mg/L PMADN-Tween 40 solution dramatically enhanced the oil recovery up to 13.4%. (C) 2017 Wiley Periodicals, Inc.