Nie Chunhong, Han Guoqiang, Ni Jiawen, Guan Shuxia, Du Huan, Zhang Yupeng, Wang Heting
College of Chemistry & Chemical Engineering, Northeast Petroleum University, Daqing 163318, China.
ACS Omega. 2021 Jul 18;6(29):19058-19066. doi: 10.1021/acsomega.1c02367. eCollection 2021 Jul 27.
The relationship model between the droplet lifetime and interface properties is established to characterize the stability of oil droplets, and then, the influence of the alkali-surfactant-polymer (ASP) concentration on the lifetime is analyzed by theoretical calculations. The stability dynamic characteristics of oil-in-water (O/W) emulsions from ASP flooding were evaluated using the emulsion stability model (Civan model) based on two-phase separation. The effect of ASP on dynamic characteristics of the emulsion was explored by analyzing film strength qualitatively and measuring interfacial tension and ζ potential. The results showed that the Civan model was suitable to evaluate the stability of the O/W emulsion and to obtain the corresponding dynamic characteristics. The O/W emulsions became more stable with the increasing alkali concentration first at a low alkali concentration ( < 200 mg/L) and then became less stable with the increasing alkali concentration at a high alkali concentration ( > 200 mg/L). The stabilities of O/W emulsions were improved with the increasing concentrations of the surfactant and polymer. The mechanism of stabilization of the O/W emulsion by ASP is as follows. The surface-active substances formed by the reaction of alkali and acidic substances in the oil phase, together with surfactants, adsorb at the oil-water interface, reducing the interfacial tension and increasing the strength of the oil-water interface film. The polymer only increases the strength of the interface film by increasing the viscoelasticity of the oil-water interface film.
建立了液滴寿命与界面性质之间的关系模型以表征油滴的稳定性，然后通过理论计算分析了碱-表面活性剂-聚合物（ASP）浓度对液滴寿命的影响。基于两相分离，使用乳液稳定性模型（Civan模型）评估了ASP驱油过程中形成的水包油（O/W）乳液的稳定性动态特征。通过定性分析膜强度以及测量界面张力和ζ电位，探讨了ASP对乳液动态特征的影响。结果表明，Civan模型适用于评估O/W乳液的稳定性并获得相应的动态特征。在低碱浓度（<200mg/L）下，O/W乳液随着碱浓度的增加首先变得更稳定，而在高碱浓度（>200mg/L）下，随着碱浓度的增加则变得不太稳定。O/W乳液的稳定性随着表面活性剂和聚合物浓度的增加而提高。ASP使O/W乳液稳定的机理如下：碱与油相中酸性物质反应形成的表面活性物质与表面活性剂一起吸附在油水界面，降低界面张力并增加油水界面膜的强度。聚合物仅通过增加油水界面膜的粘弹性来提高界面膜的强度。
