低渗透油层超低界面张力化学驱油方式研究

针对目前低渗透油层水驱采收率较低的问题,在室内采用新型超低界面张力活性剂(SLB甜菜碱型)稀体系及其与相对分子质量为480万的聚丙烯酰胺复配体系,在人造低渗透均质圆柱状岩心中进行了8个方案的化学驱油方式对比研究.结果表明:对未开发或刚投入水驱的低渗透油层单独使用SLB超低界面张力活性剂驱油时,应先注活性水段塞,后进行水驱,方可获得较高的采收率;对已进行水驱且注入水接近突破的低渗透油层,在采出液含水率达98%以后,先注低分子量聚合物水溶液段塞,后注SLB超低界面张力活性水段塞,将比注入二者的复配体系段塞获得更高的采收率.

Study on ultralow interfacial tension chemical flooding in low permeability reservoirs

In accordance with the low recovery efficiency of water flooding in low permeability reservoirs, the comparative study of 8 chemical flooding schemes of surfactant (SLB Lycine type) system and surfactant-polymer compound system (relative molecular mass of 480 × 104) is carried out with the artificial isotropic cores of low permeability in the lab. The study shows: when SLB ultralow interfacial tension surfactant flooding system is applied to undeveloped or just putting into water flooding blocks, higher recovery efficiency can be obtained if the activated water slug of SLB surfactant is injected at the first time and then the traditional waterflooding is carried out; for the waterflooding blocks with the water cut of above 98% , higher recovery efficiency is obtained by injecting polymer slug firstly and then injecting the activated water slug of SLB surfactant than by directly injecting SLB surfactant - polymer compound slug.