二氧化碳响应型表面活性剂与稠油的相互作用

Interaction between Carbon Dioxide Responsive Surfactant and Heavy Oil

CO_(2)驱是提高稠油采收率的重要发展方向,使用各种助剂辅助CO_(2)进一步提高采收率是常用手段,但智能型阳离子表面活性剂与稠油之间的相互作用及其乳化降黏性能的研究鲜见报道。通过十六烷基三甲基氢氧化铵(1#)与CH_3COOH、CO_(2)反应制备了表面活性剂2#—4#,研究了1#—4#表面活性剂表面活性、对十二烷的乳化能力、1#—4#溶液与稠油的界面张力以及对稠油的乳化行为。研究结果表明,2#—4#的表面活性以及对十二烷的乳化能力与1#的变化不大;但1#对稠油会发生反相乳化,而2#—4#对稠油有明显的降黏能力。特别是CO_(2)反应比例较低时,可以与CTAOH生成一种“拟双子型”表面活性剂(4#),油水界面张力可达到10^(-3)mN/m超低数量级,乳化降黏率达98%以上。利用该类表面活性剂的温度响应的特点,通过升高温度可以加速乳状液的油水分离,从而实现驱油效果好和采出液易处理两方面的兼顾。本文研究结果对于稠油二氧化碳驱技术增效具有借鉴意义。

It is a promising way to produce heavy oil with CO_(2) flooding,and it is a common way to introduce various additives to assist CO_(2) to further enhance oil recovery.However,it is rarely reported the interaction between smart cationic surfactant and heavy oil and viscosity reduction by emulsification.In this work,a series of surfactants,i.e.,2#—4#,were prepared by reaction of hexadecyl trimethyl ammonium hydroxide(1#)with acetic acid and carbon dioxide.Besides,the surface activity and emulsifying ability of 1#—4#surfactant for dodecane,the interfacial tension between 1#—4#solution and heavy oil and the emulsifying behavior of heavy oil were studied comparatively.The results showed that the surface activity and emulsifying ability to dodecane of 2#—4#surfactant had little change with that of 1#surfactant.However,1#surfactant had reverse emulsification for heavy oil,while 2#—4#surfactant had obvious viscosity reduction ability for heavy oil.In particular,when the reaction ratio of CO_(2) was low,a“quasi-binary”surfactant(4#)could be formed with CTAOH,whose viscosity reduction rate was more than 98%and interfacial tension value could reach ultra low as 10^(-3) mN/m.Meanwhile,it was found that the synthetic surfactant was temperature-responsive and the dehydration rate was faster with temperature improving.The advantage could bring the better oil displacement effect and the easier treatment of produced liquid.The results show a prospective strategy for improving the enhanced oil recovery of carbon dioxide flooding.