分层注采三元复合驱对大庆二类油层适应性评价

为了克服传统小岩心驱油实验在宏观尺度上的局限性,制作了三层非均质性三维平板径向流物理模型,在五点法井网条件下,分别开展笼统注采三元复合驱和分层注采三元复合驱实验,研究驱替过程中三个层位沿主流线方向上压力分布状况、采出液粘度和界面张力变化情况以及三个层位上每一点处含油饱和度变化情况,对比分析两种注采方式下的驱油效果和剩余油分布特征。研究结果表明,波及效率是影响非均质油藏最终采收率的一个非常重要因素,而分层注采能够有效提高水驱阶段中渗、低渗层的波及效率;在三元复合驱开始后,驱油剂在中渗、低渗层中运移距离更远,发挥作用时间延长,基质动用程度和最终采收率大幅提高。本实验的研究结果为油田矿场开发方案的编制提供了理论指导和参考依据。

Adaptability Evaluation of Stratified Injection-production by ASP Flooding in Class II Reservoirs in Daqing Oilfield

In order to overcome the limitations of traditional small cores in macro scale, a kind of heterogeneous core model with three layers has been designed and made. On the condition of five-point well pattern method, ASP flooding of three layers general injection-production and stratified injection-production were carried out successively. Along the main flow direction in the process of displacement, recording the pressure distribution, produced fluid viscosity, interfacial tension changes and changes of oil saturation at every point in three layers. Oil displacement efficiency and residual oil distribution by two kinds of injection and production methods can be studied. The results show that, sweep efficiency is one of the most important factors affecting the ultimate recovery of heterogeneous reservoir. Stratified injection and production can improve the sweep efficiency effectively in medium and low permeable layers during water flooding stage. When ASP flooding begins, chemical agent can migrate farther in medium and low permeable layers, extending its function time. Therefore, the utilization degree and ultimate recovery rate are greatly improved. The laboratory results can provide theoretical guidance and experimental basis for oilfield application.