用于注聚驱后的含有中强缓冲碱三元复合体系研究

Studies on the ASP compound system with moderate basic strength alkali after polymer injection flooding

针对胜利油田孤岛河滩油区注聚驱后,开展改性天然羧酸盐/缓冲碱/聚合物三元复合驱研究。先对改性天然羧酸盐SDCM-2的界面活性及其影响因素进行了系统的研究,然后通过室内物理模型实验,研究了水驱、聚驱、缓冲碱ASP复合驱的驱油效果,当复碱质量分数为1.5%(碳酸钠与碳酸氢钠质量比为1:1),SDCM-2质量分数仅为0.1%时油水界面张力就能达到超低;在注聚驱后,缓冲碱ASP复合驱室内驱油效率为18%OOIP;最后开展可视化微观模型驱油实验,直接观察了流体在孔隙介质内的流动形态。实验结果为:ASP体系进入模型中,能够使注聚后束缚残余油重新启动,使油块变形、拉细,通过毛细管喉道,渐渐形成油墙向出口处运移。表明缓冲碱ASP复合驱能够有效扩大波及体积、提高洗油效率,从而使驱油效率得到有效提高,该方法是注聚后提高采收率的有效方法之一。

Modified natural earboxylate/buffer base/polymer flooding was studied for the Gudao River Shoal Oil of the Shengli Oil Field after polymer injection flooding. First, interfacial activating and the influence of modified natural carhoxylate , i.e., SDCM-2 was systematically investigated. Then, the effects of water flooding, polymer flooding and buffer base ASP flooding were studied by laboratory physical simulation experiments. When the concentration of mixed alkali （ m （ Na2 CO3 ） ： m （ NaHCO3 ） = 1：1） is 1.5% and the concentration of SDCM-2 is 0. 1%, the oil-water interfacial tension reaches to a ultra-low level. The flooding efficiency of buffer base ASP flooding is 18% OOIP after polymer injection flooding. Finally, a visualized microscopic simulation flooding experiment was developed and the flow pattern of fluid in porous media was directly observed. Results show that the binding residual oil after polymer flooding deforms to be thinner and longer, then forms an oil bank through the capillary throat and moves to exit when the ASP system is added into the model. It is also shown that buffer base ASP flooding can improve flooding efficiency apparently by enlarging the swept volume and advances washing oil efficiency. Buffer base ASP flooding is one of the efficient methods to enhance recovery efficiency.