特高含水油藏复合驱技术提高采收率研究

Study on Combination Flooding Enhanced Oil Recovery Technique in Ultra-High Water Cut Reservoir

刘艳华 孔柏岭 肖 磊 吕晓华 束华东 林 杨

LIU Yan-Hua，KONG Bai-Ling，XIAO Lei，LV Xiao-Hua，SHU Hua-Dong，LIN Yang

针对双河油田IV5-11层系特高含水油藏条件，筛选出SP二元复合体系、ASP三元复合体系的优选配方，分别为2000 mg/L表面活性剂SH6+1500 mg/L聚合物ZL-II和8000 mg/L Na2CO3 +2000 mg/L表面活性剂SH6+1500 mg/L聚合物ZL-II，并对比评价了两种体系的热稳定性能、多次吸附性能和岩心驱油效果。实验结果表明，在81℃、7.34 s-1下优选出的SP二元体系、ASP三元体系的黏度分别为74.6 mPa·s和46.5 mPa·s，与原油间的界面张力分别为3.64×10-3和3.89×10-4 mN/m， ASP三元体系与SP二元体系相比，界面张力有一个数量级的下降，黏度下降37%。81℃老化120 d后，APS三元体系的黏度保留率高于SP二元体系，界面张力始终维持在10-4 mN/m数量级，较SP二元体系低两个数量级，长期稳定性能优越于SP二元体系。ASP三元体系在与天然油砂重复接触5次以后，界面张力从3.63×10-4 mN/m增至4.67×10-3 mN/m，仍维持在超低数量级，且非均质岩心驱油效果整体比SP二元体系高3%～5%。因此采用三元复合驱技术作为双河油田IV5-11层系在特高含水阶段水驱后大幅度提高采收率的接替技术。经过两年的的矿场试验，区块已经见到较好的增油降水效果。

The optimal formula and thermal stability, repetitious adsorption capacity, core displacement experiment of surfactant/polymer (SP) and alkali/surfactant/polymer (ASP) combinational flooding system were studied for ultra-high water cut reservoirs in IV5-11 layers Shuanghe oil filed. The experimental results showed that the optimized SP system and ASP system, composed of 2000 mg/L surfactant SH6+1500 mg/L polymer ZL-II, 8000 mg/L Na2CO3 +2000 mg/L surfactant SH6+1500 mg/L polymer ZL-II，respectively, had high viscosity(74.6 mPa·s and 46.5 mPa·s, respectively) and ultra low interfacial tension properties(3.64×10-3 and 3.89×10-4 mN/m, respectively). Compared with SP system, the interfacial tension of ASP system had a magnitude of decline, and the viscosity of ASP system decreased by 37%. With the condition of 81℃ aging for 120 days, ASP system had higher viscosity retention rate and lower interfacial tension compared with that of SP system, indicating that ASP system possessed more superior thermal stability. After repeatable adsorption at natural oil sand for five times, the interfacial tension between ASP system and the crude oil increased from 3.63×10-4 mN/m to 4.67×10-3 mN/m, still being ultra low order of magnitude. The heterogeneous core displacement experiments showed that ASP compound flooding after water flooding finished, the enhanced oil recovery were 3%—5% higher than that of SP compound flooding. Therefore, ASP compound flooding was applied in IV5-11 layers Shuanghe oil filed as a replacing technology at ultra-high water cut stage. Through about two year’s field test, good effect of increasing oil and decreasing water appears.