表面活性剂复配提高超低渗油藏渗吸采收率

Surfactant Combination for Improving the Imbibition Recovery of Ultra-low Permeability Reservoir

康万利 赵 晗 邵 硕 张向峰 朱彤宇 杨红斌

KANG Wanli，ZHAO Han，SHAO Shuo，ZHANG Xiangfeng，ZHU Tongyu，YANG Hongbin

超低渗油藏开发主要靠压裂渗吸开采基质原油，但通常水驱渗吸采收率低，而表面活性剂复配可以提高渗吸采收率。通过对复配体系的性能分析，探讨表面活性剂体系复配对超低渗油藏渗吸采收率的影响规律。针对阴离子表面活性剂HABS、非离子表面活性剂APG1214及两者复配体系，采用渗吸瓶试法测定不同体系处理岩心的渗吸采收率效果；研究了渗吸体系与原油之间的界面张力、岩心经渗吸体系浸泡前后的接触角变化、体系乳状液稳定性3种因素对采收率的影响。结果表明，岩心在复配体系中的自发渗吸采收率最高（10.43%），而HABS体系仅为4.57%，KCl体系只有2.2%，APG1214体系不能发生渗吸。复配体系与原油间的界面张力能达到10-2mN/m数量级，并可将强水湿岩心转变为润湿角接近90o的弱亲油岩心，同时复配体系易与油生成乳液且乳液易聚并。岩心驱油实验中，复配体系的注入压力最小，采收率增幅最大。超低渗油藏渗吸采油率的提高需要低界面张力、偏中性润湿的超低渗岩心，易生成可聚并的乳状液，乳状液过于稳定不利于渗吸采油。图4表2参16

Fracturing and imbibition was the main method to extract matrix crude oil of ultra-low permeability reservoirs. But the oil recovery rate of water imbibition was lower than economic need，while using the surfactant combination could improve the imbibition recovery factor. The influence rules of the combined surfactant system on the imbibition recovery of ultra-low permeability reservoirs were discussed by performance analysis. For the anionic surfactant HABS，nonionic surfactant APG1214 and their combination system，the osmotic bottle test was used to determine the imbibition recovery. The effects of three factors on oil recovery rate including interfacial tension between oil and formation，contact angle of cores before-and-after soaking in surfactant and the stability of emulsion were analyzed. The results showed that the imbibition recovery rate of the compound system was the highest one（10.43%），that of HABS and KCl system was 4.57% and 2.2%，and APG1214 system couldn’t extract oil by imbibition.The interfacial tension（IFT）between combination system and oil could reach 10-2 mN/m. The combination system could exchange the wettability of cores from hydrophilic to weak hydrophobic which contact angle was nearly 90o，and the system was easy to form emulsion which was easy to coalesce. In the displacement experiments，the injected pressure of combined system was the lowest one and the enhanced oil recovery rate was the highest one. Lower IFT，intermediate-wet reservoir and unstable emulsion were favorable conditions of imbibition，while the emulsion with extremely high stability was helpless.

10.19346/j.cnki.1000-4092.2019.04.019