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

摘要： 聚合物驱是一项成熟的化学驱提高采收率技术，目前矿场主要应用干粉类聚合物产品，因此需要在地面大规模建设溶解、熟化设备，将干粉类聚合物溶解成高黏溶液，然后将其经注聚管柱并通过炮眼注入油藏。在此过程中，聚合物溶液受到强剪切，黏度严重损失，对聚合物驱推广及规模应用效果产生较大影响。利用聚氨酯微胶囊为壳材对乳液型聚合物颗粒进行包裹，制备成微胶囊乳液型聚合物。该类聚合物微观形貌为表面平滑的圆球颗粒，粒径分布在100~600 nm，呈双峰分布；微胶囊在水中可通过缓慢溶胀破裂，实现溶液缓释增黏；与乳液型聚合物相比，微胶囊乳液型聚合物经机械剪切后的黏度损失率仅为4.7%，并可有效降低剪切作用对聚合物分子链造成的机械降解。利用物理模拟实验对微胶囊乳液型聚合物的岩心内缓释增黏性能进行研究的结果表明，微胶囊乳液型聚合物具有良好的缓释增黏能力。微胶囊乳液型聚合物还具有在线配注、缓释增黏、抗剪切等潜力，具备较大的研究价值及应用前景。

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