低渗油藏二元复合驱协同机理研究

Study on mechanism of binary compound flooding in low permeability reservoir

为探究低渗透油藏二元复合驱中聚合物和表面活性剂的协同作用机制,室内系统开展了聚合物HF和表面活性剂NPAC的吸附性能测定实验和不同岩心驱替实验。研究结果表明:在天然露头砂人造均质岩心上,二元复合驱的驱油效果主要是由聚合物贡献的,二元复合驱采收率仅比单一聚合物驱提高2.21%,单一表面活性剂驱仅在水驱基础上提高4.88%;表面活性剂NPAC在石英砂岩心上具有较好的驱油效果,采收率提高幅度可达9.3%,远高于天然露头砂岩心,同时二元复合驱的采收率比单一聚合物驱提高5.07%,协同驱油作用明显;低渗油藏二元复合驱时,表面活性剂不仅可以降低原油界面张力提高采收率,还具有降低注入压力的作用,二元复合体系在石英砂人造岩心的注入压力远低于单一聚合物体系的注入压力。

In order to explore the synergistic action mechanism of polymer and surfactant in binary composite flooding of low permeability reservoir,the adsorption performance test of polymer HF and surfactant NPAC and the displacement experiment of different cores were carried out systematically in laboratory.The results show that:on the artificial homogeneous core of natural outcrop sand,the oil displacement effect of binary composite flooding is mainly contributed by polymer,the recovery of binary composite flooding is only 2.21%more than that of single polymer flooding,and that of single surfactant flooding is only 4.88%higher than that of water flooding.The surface active agent NPAC has good oil displacement effect on quartz sandstone core,and the recovery increase can reach 9.3%.At the same time,the recovery of binary compound flooding is 5.07%higher than that of single polymer flooding,andthe synergistic oil flooding is abvious.In low permeability reservoir,surfactant can not only reduce the interfacial tension of crude oil,but also reduce the injection pressure.The injection pressure of binary composite system in quartz sand artificial core is much lower than that of single polymer flooding.