Adaptability of a hydrophobically associating polyacrylamide/mixed-surfactant combination flooding system to the Shengli Chengdao oilfield

ABSTRACT We investigated the performance of a combination flooding system composed of hydrophobically associating polyacrylamide (HAPAM) and a mixed surfactant [fatty acid disulfonate anionic gemini surfactant (DMES) plus the nonionic surfactant Triton X‐100 (TX‐100)] under the reservoir conditions of the Shengli Chengdao oilfield. With 1800 mg/L HAPAM and 300–3000 mg/L mixed surfactant, the surfactant–polymer (SP) flooding system reached an ultralow oil–water interfacial tension, and the viscosity of the system was greater than 40 mPa s. After the solution was aged for 120 days, its viscosity was still more than 40 mPa s; this indicated a good aging stability. The core flooding experiments with different porous media permeabilities showed that the SP flooding system created a higher resistance factor and residual resistance factor. In addition, the indoor flooding experiments indicated that the SP combination flooding system increased the enhanced oil recovery by more than 30% over that of the original oil in place compared with the water flooding system. Therefore, it was feasible to use an SP flooding system in the Chengdao oilfield. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 40390.