水驱突破前后注聚对聚合物驱效果影响

在油藏尺度上,聚合物可以通过提高驱替相的粘度进而将驱替相波及效率大幅度的增加。无论是水驱还是聚驱原油,微观波及范围的大小决定了宏观的驱油效果,注入时机就是影响波及效果其中一个关键因素。因此,本文以水驱突破时刻为注聚时机的分界点,采用微观可视化实验,研究不同注入时刻对非均质模型原油波及效率和采收率的影响,对比分析最佳注入时机。结果表明：水驱突破前转注聚可以使采收率达到50.26 %,直接注聚的采收率为40.01 %,水驱突破后转注聚的采收率为35.18 %。而且水驱突破前转注聚中,残余油分布以油水混合状和孤滴状,其次是斑块状和网络状。表明突破前转聚效果最好,为最佳的聚合物注入时机。

Effect of Injection Timing on Micro Wave Propagation Efficiency of Polymer Flooding

At the reservoir scale, the polymer can increase the sweep efficiency of the displacing phase by increasing the viscosity of the displacing phase. Whether it is water flooding or polymer flooding, the size of the micro sweep determines the macro oil displacement effect, and the injection timing is one of the key factors affecting the sweep effect. Therefore, in this paper, the breakthrough time of water flooding is taken as the cut-off point of the injection timing, and microscopic visualization experiment is adopted to study the influence of different injection times on the sweep efficiency and recovery rate of heterogeneous crude oil model, and the optimal injection timing is compared and analyzed. The results show that the recovery rate can reach 50.26 % before water flooding breakthrough, 40.01 % after direct polymerization, and 35.18 % after water flooding breakthrough. Moreover, in the water drive breakthrough, the residual oil is distributed in the form of oil-water mixture and solitary droplet, followed by patch and network. The results indicate that the best time for polymer injection is the pre-breakthrough polymerization.