Progress and Prospects of In Situ Polymer Gels for Sealing Operation in Wellbore and Near-Well Zone

In situ polymer gels have been received as a useful tool for sealing operations such as fluid loss control during well drilling and workover and completion, well stimulation, water shutoff, wellbore integrity, and wellbore pressure management. With the development of deep-sea, deep-earth, and unconventional reservoirs, various harsh conditions such as high temperature, high pressure, and complex working conditions pose great challenges to the performance of gels. This paper first summarizes the application and operating mechanism of in situ polymer gels for sealing operations in wellbore and near-wellbore zones. Then, the in situ polymer gels are categorized into three types, in situ monomer gels, in situ cross-linked gels, and in situ generated foam gels, and the advantages and disadvantages of these three types of gels are introduced. Second, an overview of performance improvement methods for in situ polymer gels is highlighted, including improved temperature resistance and strength, accelerated gelation, retarded gelation, gel-breaking methods, and self-degradation systems. Finally, the challenges and prospects of in situ polymer gels for sealing operation in wellbores and near-well zones are presented, to provide references for the application, formulation, and performance improvement of in situ polymer gels.