关键词: 聚合物驱, 微胶囊乳液型聚合物, 缓释增黏性能, 抗剪切性能, 在线配注

Abstract: Polymer flooding is a mature technology for enhancing oil recovery by chemical flooding. At present, dry powder polymer products are mainly applied in the mine field. It is necessary to set up large-scale dissolution and curing equipment on the ground to dissolve the dry powder polymers into high-viscosity solution, and then inject the solution into oil reservoirs through embrasures via polymer-injection pipe string. In this process, the polymer solution is subject to strong shear, whose viscosity is seriously damaged, exerting a great impact on the promotion scale and application effect of polymer flooding. Polyurethane (PU) microcapsules were used as shells to wrap emulsion polymer particles, so as to prepare microencapsulated emulsion polymers. The micromorphology of such polymer is characterized by spherical particles with smooth surfaces, and the particle size is ranged between 100 nm and 600 nm, showing a bimodal distribution; the microcapsules can be slowly swelled and broken in water to achieve slow release and thickening; compared with emulsion polymer, the viscosity loss rate of microencapsulated emulsion polymer after mechanical shearing is only 4.7 % , from which it can be found that microcapsules can effectively reduce the mechanical degradation by shear effect on polymer molecular chains. A physical simulation experiment was performed to investigate the slow release and thickening performance of microencapsulated emulsion polymer in the core. The experiment results indicated that the microencapsulated emulsion polymer has a good slow release and thickening ability. In conclusion, the microencapsulated emulsion polymer has the potential for online injection distribution, slow release and thickening, and shear resistance, and possesses great research value and application prospects.

Key words: polymer flooding, microencapsulated emulsion polymer, slow release and thickening performance, shear resistance, online injection allocation