Abstract:           In view of the typical heterogeneous block of Daqing Oilfield，core displacement experiments are carried out and study on laboratory physical simulation of surfactant/polymer-alternating-nitrogen foam flooding has been introduced by using positive rhythm heterogeneous artificial core. The injection parameters of the system are optimized and the feasibility of improving oil recovery for low interfacial tension surfactant/polymer-alternating-nitrogen foam flooding is discussed. The experimental results show that when the total injection of the oil displacement systems is kept as a fixed value, the enhancement in oil recovery is different under the condition of the same water flooding recovery with changing of the alternating way of low interfacial tension surfactant/polymer and nitrogen foam. The injection pattern of injecting 0.05 PV foam base fluid+0.05 PV N²⁺0.10 PV low interfacial tension surfactant/polymer in a single cycle with 0.20 PV cyclic injection volume and 3 alternating rounds is the optimal injection pattern. And the stage recovery is the highest under this injection pattern, which can further improve oil recovery by about 21.82% based on water flooding.

Key words: Low interfacial tension binary system, Foam system, Alternating injection, Improving oil recovery

摘要：         针对大庆油田的典型非均质区块,利用三层正韵律非均质人造岩心,进行了岩心驱替实验,开展了二元与泡沫交替驱油体系室内物理模拟研究,对体系的注入参数进行了优化,并探讨了低界面张力表面活性剂/聚合物(SP)二元体系与泡沫体系交替注入来提高采收率的可行性。结果表明,在水驱采收率接近的情况下,保持驱油体系总注入量一定,低界面张力二元体系与泡沫体系的交替方式不同,提高采收率的幅度不同。单周期注入0.05 PV泡沫基液+0.05 PV N₂+0.10 PV低界面张力二元体系,周期注入量为0.20 PV,交替轮次为3次的注入方式为最优注入方式,该注入方式下交替驱油体系的阶段采收率最高,在水驱的基础上提高了21.82%。

关键词: 低界面张力二元体系, 泡沫体系, 交替注入, 提高采收率