Rheological Properties, Temperature and Salinity Resistant Mechanism of a Novel Adamantane-Based Amphiphilic Polymer

Amphiphilic polymer has excellent thickening ability and shear resistance properties compared with conventional polymer for enhanced oil recovery (EOR) process. However, its viscosity would be rapidly decreased in high-temperature and high-salinity reservoirs. Herein, a novel amphiphilic polymer (PAMN) for oil displacement was optimized and synthesized by introducing adamantane groups through micelle polymerization method, to improve the temperature and salinity resistance of amphiphilic polymer. Use Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance H spectrometer (1H-NMR) to characterize the chemical structures of the developed temperature and salt resistant amphiphilic polymer (PAMN). Moreover, the rheological properties of PAMN were studied by MCR rheometer under the high-temperature and high-salinity conditions in Shengli Oilfield. The research results indicate that the critical association concentration (CAC) of PAMN is about 2700 mg/L, and the viscosity can reach to 40 mPa·s at CAC. A dense three-dimensional network structure is formed in the polymer solution, which significantly increases the hydrodynamic radius of polymer molecules and significantly increases the solution viscosity. The introduction of rigid groups of adamantane improves the temperature and salt resistance of amphiphilic polymers in aqueous solutions to 90 ℃ and 20 × 104 mg/L, respectively. At 85 ℃, PAMN solution still exhibits good viscoelastic properties, which is beneficial for improving the swept volume and oil displacement efficiency in high-temperature and high-salinity reservoirs. Therefore, this polymer has good EOR application prospects in high-temperature and high-salinity reservoirs.