高盐油藏下两性/阴离子表面活性剂协同获得油水超低界面张力

Ultra-Low Interfacial Tension in High Salinity Reservoir Driven by Synergistic Interaction of Zwitterionic and Anionic Surfactants

研究了在高盐油藏中,利用两性/阴离子表面活性剂的协同效应获得油水超低界面张力的方法.两性表面活性剂十六烷基磺基甜菜碱与高盐矿化水具有很好的相容性,但在表面活性剂浓度为0.07%-0.39%(质量分数)范围内仅能使油水界面张力达到10-2mN·m-1量级,加入阴离子表面活性剂十二烷基硫酸钠后则可与原油达到超低界面张力.通过探讨表面活性剂总浓度、金属离子浓度、复配比例对油水动态界面张力的影响,发现两性/阴离子表面活性剂混合体系可以在高矿化度、低浓度和0.04%-0.37%的宽浓度范围下获得10-5mN·m-1量级的超低界面张力,并分析了两性/阴离子表面活性剂间协同获得超低界面张力的机制.

The present work investigates the use of synergistic interactions between zwitterionic and anionic surfactants to obtain ultra-low interfacial tension （IFT） in a high salinity reservoir.Zwitterionic surfactant N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate was found to be compatible with simulated high salinity water,reducing crude oil/water interfacial tension to a magnitude of 10-2mN·m-1 in a surfactant concentration range of 0.07%-0.39% （mass fraction）,whereas ultra-low IFT was obtained by adding anionic surfactant sodium dodecyl sulfate.Furthermore,the effects of total surfactant concentration,metal ion concentration,and molar ratio on the dynamic interfacial tension of zwitterionic/anionic surfactant mixtures were studied.Results showed that 10-5mN·m-1 magnitude ultra-low IFT was obtained over a wide range of surfactant concentrations from as low as 0.04% and up to 0.37% in high salinity water.The synergistic mechanism of ultra-low IFT formed in zwitterionic/anionic surfactant systems was further analyzed.