Winsor相图法研究盐和醇对十二烷基甜菜碱体系驱油性能的影响

Effect of Salt and Alcohol on the Displacement Performance of Dodecyl Dimethyl Betaine Microemulsion System Using Winsor Phase Diagram Method

为获得驱油性能良好的十二烷基甜菜碱(BS-12)体系,通过Winsor相图法研究了NaCl和正丁醇加量对十二烷基甜菜碱/正丁醇/正己烷/NaCl微乳液体系相态变化的影响,及相体积变化对微乳液增溶能力及界面张力的影响,评价了按最佳配方制备的BS-12微乳液体系的驱油性能。结果表明,NaCl和正丁醇对微乳液相态的影响较大。随NaCl和正丁醇加量增大,微乳液相态经历WinsorⅠ型到WinsorⅢ型再到WinsorⅡ型的转变。4%BS-12、9.3%正丁醇、3.8%NaCl形成的WinsorⅢ型(中相)微乳液(油水比1∶1)增溶能力最强、界面张力最低、驱油潜力最大。室内岩心驱替结果表明,该中相微乳液增油降水效果较好,可在水驱基础上降低含水率9.4%、提高采收率8.34%。

In order to obtain dodecyl dimethyl betaine（BS-12）microemulsion system with good oil displacement performance,the effect of NaCl and n-butanol dosage on the phase change of BS-12/n-butanol/n-hexane/NaCl microemulsion was studied through Winsor phase diagram method,and the influence of phase volume change on the solubilization and interfacial tension of microemulsion was also studied. The oil displacement performance of BS-12 microemulsion system prepared according to the optimum formula was evaluated. The results showed that NaCl and n-butanol had great influence on the phase state of microemulsion. The phase of microemulsion had undergone the transition from WinsorⅠ to Winsor Ⅲ and Winsor Ⅱ with increasing addition of NaCl and n-butanol. The Winsor Ⅲ（middle-phase）microemulsion（1∶1 oil-water ratio）formed by 4% BS-12,9.3%n-butanol and 3.8% NaCl had the strongest solubilization ability,the lowest interfacial tension and the largest oil displacement.continuedfromp.124）potential. The results of indoor core displacement showed that the middle-phase microemulsion could reduced water content by9.4% on the basis of water flooding and increased recovery rate by 8.34%,indicating good effect of enhancing oil recovery and reducing water cut.