Polymer flooding is a key technology for improving reservoir heterogeneity around the world, and it has made great progress. However, the traditional polymer has many shortcomings in the theory and application, which causes the efficiency of polymer flooding to gradually decrease and secondary reservoir damage after a long period of polymer flooding. In this work, a novel polymer particle (soft dispersed microgel, SMG) is used as the research object to further investigate the displacement mechanism and reservoir compatibility of SMG. The visualization experiments of the micro-model prove that SMG has excellent flexibility and can be highly deformable to realize deep migration through the pore throat smaller than SMG itself. The visualization displacement experiments of the plane model further show that SMG has a plugging effect, which makes the displacing fluid flow into the middle and low permeability layers, improving the recovery of these layers. The compatibility tests show that the optimal permeability of the reservoir for SMG-μm is 250-2000 mD, and the corresponding matching coefficient range is 0.65-1.40. For SMG-mm-, its corresponding optimal permeabilities of reservoir and matching coefficient are 500-2500 mD and 1.17-2.07, respectively. The comprehensive analysis demonstrates that the SMG has excellent ability of the water-flooding swept control and compatibility with reservoirs, having the potential to solve the problem of traditional polymer flooding.
Keywords: EOR; displacement mechanism; reservoir compatibility; soft dispersed microgel; visualization experiment.