油滴的宏观聚并机制及油膜分子之间的微观相互作用研究

Study of Macroscopic Aggregation Mechanism of Oil Droplets and Microscopic Interactions Between Oil Film Molecules

为研究油滴聚并过程中油滴之间的微观相互作用,通过有限元模拟方法,结合乳状液稳定性实验与分子动力学模拟技术,研究了油井采出液中乳化油滴的聚并行为,并分析了油滴聚并的影响因素。研究结果表明:2个油滴在聚并过程中液膜位置处流体流速较高,聚并完成后达到稳定;油滴尺寸与聚并时间并不存在明显的对应关系,当2个油滴半径不同时,较大的油滴移动位移较小;初始时刻,油膜和水相之间存在明显的界限;碳链越长,乳状液越稳定,在碳原子数量相同的条件下,原油组分对乳状液稳定性的影响由小到大为饱和烃、碳碳双键、碳碳三键、环烷烃;沥青质含量升高是造成乳状液体系乳化能力和乳化稳定性增强的主要原因。该研究对提高原油油水分离效率,降低原油储运成本有重要意义。

In order to study the microscopic interactions between oil droplets in the process of oil droplet coalescence,the coalescence behavior of emulsified oil droplets in oil well recovery fluid was studied by finite element simulation method,in combination with the emulsion stability experiments and molecular dynamics simulation technology,and the influencing factors of oil droplet coalescence were analyzed.The study results show that the fluid flow rate is relatively high at the location of the liquid film during the coalescence of the 2 oil droplets,and reaches stability after the coalescence is completed.There is no obvious correspondence between the size of oil droplets and the coalescence time,and when the radii of 2 oil droplets are different,the larger droplets move less;at the initial moment,there is an obvious boundary between oil film and water phase;the longer the carbon chain,the more stable the emulsion;under the condition of the same number of carbon atoms,the influence of crude oil components on the stability of emulsion is from small to large for saturated hydrocarbons,carbon-carbon double bonds,carbon-carbon triple bonds,and cycloalkanes;the increase of asphaltene content is the main reason for the increase of emulsification capacity and emulsion stability of emulsion system.This study is of great significance to improve the oil-water separation efficiency of crude oil and reduce the cost of crude oil storage and transportation.