A review on viscosity retention of PAM solution for polymer flooding technology

Polyacrylamide (PAM) is one of the most critical materials in polymer flooding technology. However, the reservoir environment with high temperature, high pressure and high salinity will degrade PAM, which will reduce its viscosity and affect the recovery rate. In addition, previous studies lacked in-depth research on the PAM degradation mechanism and viscosity stabilization strategies. Therefore, the degradation mechanism of PAM solution in polymer flooding technology (including mechanical degradation, thermal degradation, free radical degradation, and biodegradation) and corresponding anti-degradation measures was introduced in this study, which provides a general strategy for effectively maintaining the viscosity of PAM solution. The conclusion shows that in order to maintain the viscosity of PAM solution, introducing functional monomer to modify PAM is the most essential and effective strategy. The combination of chemicals resistant to free radical degradation can further reduce viscosity loss and enhance oil recovery. The results of this study provide a comprehensive and systematic viscosity stabilization strategy that is important for PAM to reduce viscosity losses and enhance oil recovery in polymer flooding applications. In addition, modified PAM with low cost and resistance to free radical degradation should be developed in the future to meet the trend of future oil and gas resource development.