特高含水后期提高采收率物理模拟实验

为了探索特高含水后期剩余油的潜力区和不同驱油方法提高采收率的机理，采用三维大模型物理模拟实验，研究了高倍数水驱、活性剂驱、聚合物驱、二元复合驱、微球-乳化剂驱过程中注入压力、波及系数的变化情况和剩余油饱和度的分布特征。研究结果表明，特高含水后期提高采收率的潜力区为未波及区的剩余油和已波及的弱水洗区和中水洗区，而不是强水洗区；继续高倍数水驱和超低界面张力活性剂驱不能进一步扩大波及系数，提高采收率潜力小，需采用深部调堵+微调驱油相结合的技术。自聚集微球-乳化剂驱具有封堵-驱替-再封堵-再驱替的特点，可扩大波及系数38.6%，提高采收率19.1%，其封堵能力、波及范围和驱油效率均明显高于聚合物驱和二元复合驱，具有良好的应用前景。

Physical simulation experimental study on the enhanced oil recovery in the late stage of ultra-high water cut

In order to search for remaining oil potential areas in the late stage of ultra-high water cut and explore the enhanced oil recovery (EOR) mechanisms of different oil displacement methods, this paper carried out physical simulation experiment of 3D large model to analyze the variation of injection pressure and sweep efficiency and the distribution characteristics of remaining oil saturation in the process of high-expansion water flooding, surfactant flooding, polymer flooding, binary compound flooding and microsphere emulsifier flooding. It is indicated that EOR potential areas in the late stage of ultra-high water cut are the unswept remaining oil areas and the swept weak and moderate water flushed areas instead of strong water flushed areas. The sweep efficiency cannot be increased further if high-expansion water flooding or ultra-low interfacial tension surfactant flooding is continued, which verifies that their EOR potential is low. And it is necessary to adopt the combination technology of in-depth plugging control and micro-flooding control. Self-aggregating microsphere emulsifier flooding has the advantage of plugging, displacement, re-plugging, re-displacement, and it can increase sweep efficiency and recovery factor by 38.6 % and 19.1 %, respectively. Compared with polymer flooding and binary compound flooding, it is much better in terms of plugging capacity, sweep area and oil displacement efficiency and presents promising application prospect.