针对致密油藏经“水平井+体积压裂”技术改造开发后井间流体发生窜流及致密油采收率偏低的问题,研制了一种高起泡强渗吸纳米驱油剂。以自研双子表面活性剂BD-2、CHSB、LAB为纳米驱油剂的主剂,通过三元相图法得出纳米驱油剂的配方为:25 % BD-2+10 % LAB+4.5 % CHSB+5 %油溶性增效剂+15.5 %小分子醇。对纳米驱油剂界面性能、润湿调节性能、渗吸性能、起泡性能、耐温抗盐性能、增容性能、静态洗油性能进行评价,同时研究了驱油剂对岩心中致密油动用情况。结果表明,在2 000 mg/L下,纳米驱油剂YYC-2与玛湖原油的界面张力可达6.318×10^-3 mN/m,可将接触角降低至20.36°,渗吸采出程度达到21.37 %;在90 ℃、10×10⁴ mg/L NaCl和5×10³ mg/L CaCl₂矿化度下均能达到超低界面水平,最大增容粒径可达593.6 nm,静态洗油效率最大可达80 %左右。高压压汞曲线与核磁共振曲线的转换系数C为791 nm/ms,能启动岩心最小孔隙直径为20.030 4 nm。

After the "horizontal well+volume fracturing" technology transformation and development has been performed in tight oil reservoirs,there appear the problems that cross flow happens between wells' fluid and the recovery rate of tight oil becomes low.In order to solve these problems,a high foaming and strong permeable nano oil displacement agent is developed.The self-developed gemini surfactants including BD-2,CHSB and LAB are used as main agents of nano oil displacement agent,the formula of nano oil displacement agent is obtained through ternary phase diagram method as follows:25 % BD-2+10 % LAB+4.5 % CHSB+5 % oil-soluble synergist+15.5 % small molecule alcohol.The interfacial properties,wetting adjustment performance,imbibition performance,foaming performance,temperature resistance,salt resistance,compatibilization performance and static oil washing performance of the agent are evaluated.Meanwhile,the application of the nano oil displacement agent to tight oil in core is studied.The results show that at 2 000 mg·L^-1,the interfacial tension between YYC-2 nano oil displacement agent and Mahu crude oil can reach 6.318×10^-3 mN·m^-1,and the contact angle can be reduced to 20.36°.The degree of imbibition recovery reaches 21.37 %.It can reach the ultra-low interface level at 90℃,10×10⁴ mg·L^-1 NaCl and 5×10³ mg·L^-1 CaCl₂ salinity.The maximum compatibilized particle size can reach 593.6 nm.The maximum static oil washing efficiency can reach about 80 %.The conversion coefficient between high-pressure mercury injection curve and nuclear magnetic resonance curve is 791 nm·ms^-1,and the minimum pore diameter that can start the core is 20.030 4 nm.

张利伟(1993-),男,硕士,工程师,主要从事油藏提高采收率技术研究,792873184@qq.com