Synthesis and properties of the active polymer for enhanced heavy oil recovery

Abstract

With the continued recovery of heavy oil, conventional polymer flooding cannot be applied to heavy oil reservoirs gradually due to the characteristics of heavy oil reservoirs. To study oil displacement agent suitable for enhanced heavy oil recovery and investigate the effect of EO chain length on the performances, acrylamide, acrylic acid, lauryl methacrylate and C 10 -C 16 alkylphenol ethoxylates were selected to co-polymerize into the active polymer PAAP-x with different EO chain length (14, 16, 18, 20 and 22). Proton nuclear magnetic resonance analysis indicated PAAP-x as the target product. The optimal EO chain length of PAAP-x was determined to be 18 by the analysis of thickening, salt-tolerance, interfacial activity, wettability, viscosity reduction and recovery. Compared with conventional polymer P1, 1500 mg/L PAAP-18 exhibited superior performances with salinity of 6882.2 mg/L: (1) PAAP-18 could maintain the viscosity of 113.1 mPa . s, while P1was 44.8 mPa . s. (2) PAAP-18 could reduce the water-oil IFT from 44.4 mN/m to 13.0 mN/m, while P1 was to 30.6 mN/m, and the water-oil contact angle was 58.2°and 108.5°, respectively. (3) The heavy oil viscosity reduction rate of PAAP-18 was 81.7% at 50 °C, while P1 was only 33.8%. (4) PAAP-18 enhanced heavy oil recovery by 19.85% on the basis of water flooding while conventional polymer was only 8.69%. This study has theoretical guidance and practical significance for the study on new oil displacement agent to enhance heavy oil recovery. • Active polymer PAAP with optimal EO chain length of 18 were successfully synthesized. • PAAP-18 was better than conventional polymer in performances. • PAAP-18 could enhance heavy oil recovery by 19.85% on the basis of water flooding. • PAAP-18 simultaneously improve the oil displacement efficiency and the sweep efficiency.