稠油油藏表面活性剂辅助蒸汽驱适应性评价研究

针对胜利稠油油藏条件,利用室内实验和油藏数值模拟技术,系统研究了表面活性剂辅助蒸汽驱开发效果。考察了高温表面活性剂WT的界面张力、耐温性和降黏性。结果表明,WT溶液与原油间的动态界面张力最小值达10-2mN/m。耐温可达150℃,半衰期大于15 d。油水质量比8∶2、7∶3时的降黏率分别大于86%和95%。表面活性剂辅助蒸汽驱最终采收率为74.32%,比蒸汽驱提高12.11%,增油效果明显。在驱油实验的基础上,基于数值模拟方法对孤岛中二北Ng5典型井组表面活性剂辅助蒸汽驱注入参数进行优化。最佳注入方案为:段塞交替注入,表面活性剂质量分数0.5%,注入体积0.3 PV,预测该方案提高采收率3.58%。通过动态经济评价方法,推导得到了"经济极限增油量"表达式,在此基础上建立了表面活性剂辅助蒸汽驱经济技术界限研究方法,并确定了典型井组表面活性剂辅助蒸汽驱有效厚度、原油黏度界限。

Adaptability Evaluation of Surfactant Assisted Steam Flooding for Heavy Oil Reservoir

The surfactant assisted steam flooding efficiency was systematically investigated by means of laboratory experiments and numerical simulation in light of the specific reservoir conditions of Shengli oilfield.Some property parameters of high-temperature surfactant(WT) such as interfacial tension,temperature resistance and viscosity reducing property were determined.Experiment results showed that the minimum dynamic interfacial tension between WT solution and oil was of 10-2 mN/m.And the temperature resistance researched to 150℃.The half-life was over 15 d.When the mass ratio of oil to water was of 8∶ 2 and 7∶ 3,the viscosity reducing rate was higher than 86% and 95%,respectively.The ultimate recovery of surfactant assisted steam flooding was of 74.32%,which improved by 12.11% comparing with steam flooding.Based on displacement experiments,the injection parameters of surfactant for the typical well group in Zhongerbei Ng5 of Gudao oilfield were optimized by numerical simulation technique.The optimum injection project was obtained as follows: alternative injection,0.5% surfactant dosage and 0.3 PV injection volume.The increasing oil recovery of the optimum plan predicted was of 3.58%.The expression of economic minimum oil increment was derived by dynamic economic evaluation.Based on this,a method for studying economic and technical boundary values of surfactant assisted steam flooding was built.Effective thickness and oil viscosity economic and technical boundary values of the typical well group were studied.