二元复合驱体系优化及转注时机实验研究

聚合物驱加剧了油藏的非均质性以及剩余油的启动难度，利用复合驱降低界面张力和流度控制协同作用能够进一步提高原油采收率。通过复配不同性能的复合体系进行室内驱油实验和转注时机研究。结果表明，复合体系中的流度控制能力和降低界面张力对驱油效果的贡献比为1.2：1.0，利用水驱特征和不同节点后续水驱特征公式的差异，建立了快速判断聚合物驱后复合体系的最佳转注时机，即后续水驱阶段即将失效阶段转注复合体系时效果最佳；实验研究的条件下优化出的复合体系是以流度控制能力为主、降低界面张力范围是10^-1~10^-2 mN/m；聚合物驱结束后开始后续水驱0.14 PV是复合驱的最佳转注时机，适宜挖掘聚合物驱后的剩余油。

An Experimental Study on the Optimization of Converting Time of Binary Combination Flooding Systems

Polymer flooding exacerbates the heterogeneity of the reservoir and the difficulty of starting the sweep of the remaining oil. The use of combination flooding to reduce the synergy between interfacial tension and fluidity control can further enhance oil recovery. Indoor flooding experiments and converting time studies were carried out using combination systems with different performances. The results show that the ratio of fluidity control and the reduction in interfacial tension to the oil displacement effect in the combination system is 1.2:1.0. Using the difference between the water flooding characteristics and the subsequent water flooding characteristic formulas of different nodes, a quick determination of optimal converting time for polymer flooding was established; i.e., the effect is best when the converting time occurs at the end of the polymer flooding and the beginning of the subsequent water flooding phase. The optimized compound system under the experimental conditions is primarily based on fluidity control, and the interfacial tension is reduced to 10^-1~10^-2 mN/m. The best converting time for compound flooding is at the beginning of the subsequent water flooding 0.14 PV after the end of the polymer flooding, which is suitable for excavating the oil remaining after polymer flooding.