三元复合驱采出水油/水界面稳定性机理研究——沥青质的影响  

Study of stability mechanism of the oil/water interface of alkali-surfactant-polymer flooding produced water: Effect of asphaltenes

作　　者：孙浩[1,2] 李晓庆[1,2] 刘丹丹 李小兵[1,2] SUN Hao;LI Xiaoqing;LIU Dandan;LI Xiaobing(National Engineering Research Center of Coal Preparation and Purification,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;School of Chemical Engineering and Technology,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China)

机构地区：[1]中国矿业大学国家煤加工与洁净化工程技术研究中心,江苏徐州221116 [2]中国矿业大学化工学院,江苏徐州221116

出　　处：《中国矿业大学学报》2022年第4期791-801,共11页Journal of China University of Mining & Technology

基　　金：国家自然科学基金项目(52004281);中国博士后科学基金项目(2020M671653);中央基本科研业务费项目(2020QN52)。

摘　　要：为探明沥青质对三元复合驱采出水油/水界面稳定性的影响,通过分子动力学模拟研究了沥青质与驱油表面活性剂(十二烷基苯磺酸钠,SDBS)分子在油/水界面的吸附行为,结合油/水界面膜的微观形貌、弹性模量及薄化破裂行为研究,明确了沥青质存在条件下油/水界面膜微观结构及界面性质的变化规律.结果表明:SDBS与沥青质分子交联形成了致密牢固的界面膜体系,这种复合界面膜结构具有较大的空间位阻,能阻碍水化膜脱稳和油滴排液,使油滴寿命延长;采出水乳液中油相沥青质含量越高,界面膜越致密平整,且黏弹性显著强化,导致采出水稳定性提升.聚醚破乳剂能破坏复合界面膜上乳化剂分子排列结构,但SDBS分子取向没有改变;而通过向聚醚分子中引入季铵盐基团,破乳剂电中和特性显著提高,结合聚醚自身优异的界面延展性,能实现复合界面膜的有效脱稳.To ascertain the influence of asphaltene on the stability of oil/water interface of alkali-surfactant-polymer flooding produced water, the adsorption behaviors of asphaltenes and oil displacement surfactant(sodium dodecyl benzene sulfonate, SDBS) at the oil/water interface were investigated by molecular dynamics simulation. Variations on the microstructure and interfacial properties of oil/water interfacial film were also monitored by microtopography and viscoelasticity characterization protocols. The results show that the dense and solid interfacial system is built by cross-linking SDBS with asphaltene molecules. The composite asphaltene-SDBS interfacial film structure has a large steric hindrance, which hinders the destabilization of the hydration shell and the oil droplet drainage, so as to further prolong the oil droplet life. For the alkali-surfactant-polymer flooding emulsions, the higher the asphaltene content is, the denser and smoother the oil/water interfacial film is, and the viscoelasticity of the interfacial film also significantly strengthens. As a result, the stability of the alkali-surfactant-polymer flooding emulsion significantly increases. Common polyether demulsifier can destroy the molecular structure of composite interfacial film, but the orientation of SDBS molecule does not change. By grafting the quaternary ammonium group, the interfacial electrical neutralization characteristics of polyether can be effectively improved. Combined with the excellent interfacial ductility of polyether, the composite interfacial film can be effectively destabilized.

关 键 词：三元复合驱 油水分离 沥青质 界面吸附 界面膜 

分 类 号：TD91[矿业工程—选矿]