Dispersion of polyacrylamide and graphene oxide nano-sheets for enhanced oil recovery

Hydrolysed polyacrylamide (HPAM) is widely used in enhancing oil production during tertiary flooding processes by improving the sweep efficiency. However, HPAM faces many challenges under high-temperature and high-salinity conditions mainly caused by the degradation. To overcome these challenges, incorporation of approprioate nanoparticles into HPAM solutions have been recently suggested to enhance its performance during the enhanced oil recovery (EOR) process. The current study specifically investigated the potential of amphiphilic graphene oxide (GO) in enhanicng the performance of HPMA. Its influences on HPAM in terms of the surface activity at the oil-water interface, the mobility behaviour, and the effectiveness in oil recovery were examined. The results revealed that adding up to 0.8 wt% of GO into HPAM reduced the oil-water interfacial tension (IFT) from 62.54 mN/m to 42.78 mN/m, and the contact angle (CA) from 71.08º to 68.84º, while in the mean time increasing the viscosity from 9.07 mPas to 16.49 mPas. Furthermore, the pilot core-flooding study demonstrated that with an addition of 0.8 wt% GO, HPAM achieved higher oil recovery rate (i.e., 76.83 %) than that of the pure HPAM (i.e., 67.39 %). The improved oil recovery performance was attributed to a better mobility ratio, resulting from the increased viscosity of the composite and reduced IFT, which was facilitated by the amphiphilic behaviour of GO, as supported by the desirability model.