宽分子量聚合物/表面活性剂复合驱油体系性能评价

Evaluation on the properties of broad-molecular-weight polymer/surfactant flooding system

为解决注水开发油藏在高含水、高采出程度开发阶段,非均质性较强、层间及层内矛盾突出而又无法实现分注的问题,提出了宽分子量聚合物/表面活性剂二元复合驱油体系。采用理论计算及室内实验的方法,评价了复合体系的性能,结果表明:宽分子量聚合物具有较好的增黏效果,与表面活性剂配伍性较好;并且同时发挥了宽分子量聚合物扩大波及的作用以及表面活性剂提高洗油效率的作用,与储层的适应性更好,可以在水驱基础上提高采收率15%以上;宽分子量聚合物中分子量配比应根据储层的渗透率划分确定,只有宽分子量聚合物体系与储层非均质情况匹配性最好时,才能取得最好的驱油效果。宽分子量聚合物复合驱油体系是一种有效的驱替体系,研究结果可以为处于双高开发期的非均质油藏提高采收率提供借鉴。

When waterflooding reservoirs are in the development stage of high water cut and high degree of reserve recovery, they are faced with the difficulties of stronger heterogeneity and obvious interlayer and intralayer contradictions, and separate injection cannot be fulfilled. In order to solve these problems, the broad-molecular-weight polymer/surfactant flooding system was proposed in this paper. In addition, its properties were evaluated by means of theoretical calculation and laboratory experiment. It is indicated that broad-molecular weight polymer has better viscosity increasing effect and it is better compatible with the surfactant. This broad-molecular-weight polymer/surfactant flooding system gives the full play to the sweeping enlargement effect of broad-molecular-weight polymer and the displacement efficiency increasing effect of surfactant, and its applicability to reservoirs is better. By virtue of this system, the recovery factor is increased by over 15% on the basis of water flooding. The molecular weight proportion of broad-molecular-weight polymer shall be determined according to the reservoir permeability. The best displacement efficiency cannot be realized unless the compatibility between the broad-molecular-weight polymer system and the reservoir heterogeneity is the best. In conclusion, the combination flooding system of broad-molecular-weight polymer is an effective displacement system. The research results can be used as the reference for EOR of heterogeneous oil reservoirs in the development stage of high water cut and high degree of reserve recovery.