特高含水油藏聚驱后非均相驱渗流规律

Research on flow behaviors of heterogeneous system after polymer flooding in ultra-high water cut reservoir

关键词:  特高含水油藏  聚驱  非均相驱  渗流规律  封堵

Key words:  ultra-high water cut reservoir  polymer flooding  heterogeneous system flooding  flow behaviors  plugging

摘要:

目的 针对特高含水油藏窜流问题严重、聚合物驱流度控制能力有限等问题,探索特高含水阶段非均相驱微观渗流特征。方法 通过微观可视化渗流实验、均质条件驱油及非均质条件调驱实验,评价了特高含水阶段水窜规律和聚驱对注水剖面的调整能力。结果 在特高含水阶段,注入聚合物和非均相体系后,驱替压差有效提高,最终采收率较水驱提高了32.8%；非均相体系的注入可在聚驱后继续动用低渗岩心中的剩余油,低渗填砂管采收率较水驱提高了38.1%。非均相体系有效动用了各类微观剩余油,含量显著降低。结论 非均相体系能够对窜流通道实现有效封堵,改善多孔介质的微观非均质性,促使驱替液转向并进入未波及区域,对剩余油实现有效的动用,进而提高原油采收率。 

Abstract:

Objective Aiming at serious problems of the water channeling at ultra-high water cut stage and the limited mobility control ability of polymer flooding, the micro-flow behaviors of heterogeneous flooding were explored. Methods The water channeling and the adjustment behavior of polymer flooding on water injection profile at ultra-high water cut stage were evaluated through the microscopic visualization displacement experiment, displacement experiment in the homogeneous porous model, and profile control and displacement experiment in the heterogeneous porous model. Results The displacement resistance was effectively improved after the injection of polymer and heterogeneous system at the ultra-high water cut stage. The ultimate oil recovery increased by 32.8 percentage points than that of water flooding. The residual oil in low permeability core after polymer flooding can continue to be used by injecting heterogeneous system. The ultimate oil recovery of low permeability sand pack increased significantly 38.1 percentage points than that of water flooding. The heterogeneous system effectively displaced all kinds of microscopic residual oil, and their content decreased significantly. Conclusion The heterogeneous system can effectively plug the channeling channel, improve the micro-heterogeneity of the porous media, promote the displacement fluid to turn and enter the unswept area, and effectively utilize the remaining oil, thereby improving the oil recovery.