Analysis on the Effect of High Concentration Slug before Stopping Polymer Injection

With high concentration or high molecular weight with high concentration plugging slug can enhance recovery further, which make full use of high concentration polymer viscoelastic before stopping polymer flooding. These layers are usually well developed and connected, and has a certain pressure rise space. We optimized two blocks for polymer flooding in this block, the two blocks inject middle molecular weight with high concentration and high molecular weight with high concentration plugging slug respectively, we optimized the molecular weight, and find out that the 25 million plugging slug is better than the 7 million. The study has important guiding significance for late stage of polymer flooding.