A review of research progress of in situ polyacrylamide gel for profile control and water plugging

Long-term water injection in oil fields has led to problems such as water breakthrough and reduced oil production. It is urgent to reduce water cut and increase oil production through profile control and water plugging measures. Polymer gel is the most widely used profile control and water plugging agent at present. To study its gelation law and profile control and water plugging performance, many researchers have carried out polymer gel gelation viscosity and strength testing experiments, physicochemical properties characterization experiments, and performance evaluation experiments. On this basis, they conducted numerical simulation of polymer gel profile control and water plugging, studied the factors affecting gelation, and achieved a series of results. In situ polyacrylamide gel has been widely studied, but to the best of our knowledge, there is still a lack of systematic review of experimental research methods, mathematical models of polymer gel profile control, and water plugging mechanisms, and factors affecting gel formation. Therefore, this paper introduces the gelation mechanism and experimental methods of polyacrylamide/metal cross-linked gel and polyacrylamide/phenol-aldehyde cross-linked gel for profile control and water plugging in oil fields. Then, the mathematical models of profile control and water plugging mechanism of polymer gel and the main factors affecting the gelation and gel performance were systematically summarized. Additionally, the paper sorts out the difficulties and shortcomings of current research, and makes a prospect, which provides a theoretical basis for future research on polymer gel system for profile control and water plugging.