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.
[1] 张朋飞,李翔.三元复合驱采出液稳定机理研究[J].油气田地面工程,2019,38(2):30-33.
ZHANG Pengfei,LI Xiang.Stabilizing mechanism study on the produced liquid of ASP flooding[J].Oil-Gas Field Surface Engineering,2019,38(2):30-33.
[2] OPAWALE F O,BURGESS D J.Influence of interfacial properties of lipophilic surfactants on water-in-oil emulsion stability[J].Journal of Colloid and Interface Science,1998,197(1):142-150.
[3] 蒋华义,孙娜娜,王舰,等.有机碱/复配表面活性剂稳定的稠油水包油乳状液的破乳研究[J].油田化学,2016,33(2):338-344.
JIANG Huayi,SUN Nana,WANG Jian,et al.Demulsification Efficiency of Heavy Oil-in-water Emulsion Stabilized by Organic Alkali and CompoundSurfactants[J]. Oilfield Chemistry,2016,33(2):338-344.
[4] 李枫,熊峰,刘彩玉,等.油滴聚并破碎行为对水力旋流器分离性能的影响[J].石油机械,2019,47(6):73-78.
LI Feng,XIONG Feng,LIU Caiyu,et al. Effect of oil droplet coalescence and breakup behavioron separation performance of hydrocyclone[J].China Petroleum Machinery,2019,47(6):73-78.
[5] 刘沙沙,张恒,苑世领,等.脉冲电场O/W乳状液破乳的分子动力学模拟[J].高等学校化学学报,2021,42(7):2170-2177.
LIU Shasha,ZHANG Heng,YUAN Shiling,et al.Molecular dynamics simulation of pulsed electric field O/W emulsion demulsification[J].Chemical Journal of Chinese Universities,2021,42(7):2170-2177.
[6] 霍进,周鹤,刘勇,等.风城油田超稠油污油处理技术[J].特种油气藏,2016,23(1):146-150.
HUO Jin,ZHOU He,LIU Yong,et al.Super heavy sump oil treatment technology in Fengcheng Oilfield[J].Special Oil & Gas Reservoirs, 2016,23(1):146-150.
[7] HUANG Bin,NAN Xiaohan,FU Cheng,et al.Study of the bubble collapse mechanism and its influencing factors on stability under ultra-low surface tension[J].Colloids and Surfaces A:Physicochemical and Engineering Aspects,2021,618(4):126-145.
[8] 吕凤霞,王剑,袁惠新,等.旋流器内油滴聚并破碎与粒径分布的数值模拟[J].自动化与仪表,2021,36(5):84-88.
LYU Fengxia,WANG Jian,YUAN Huixin,et al.Numerical simulation of oil droplets coalescence and breakage and particlesize distribution on hydrocyclone[J].Automation & Instrumentation,2021,36(5):84-88.
[9] AN Hongxin,CAO Guangsheng,BAi Yujie,et al.Study on the stability of emulsion based on molecular dynamics[J].Journal of Dispersion Science and Technology,2021,42(11):1723-1732.