钻井液与完井液2023，Vol.40Issue(5)：670-677,8.DOI:10.12358/j.issn.1001-5620.2023.05.018
分子模拟助溶剂在硅氧烷类SC-CO2压裂液中的助溶行为研究
Study on Solubilization Behavior of Molecular Simulation Cosolvent in Siloxane SC-CO2 Fracturing Fluid
摘要
Abstract
Due to the low viscosity of supercritical carbon dioxide fracturing fluid system,the method of adding tackifier is generally used to overcome the problem of low sand carrying efficiency.Siloxane tackifiers are widely used due to their low cohesive energy and good tackifying effect,but it is necessary to add cosolvent to improve the dissolution effect.Therefore,in this paper,the widely used polydimethylsiloxane was selected as the research object,and the effect of the addition of cosolvents such as methanol,toluene and cyclohexane on the dissolution behavior of polydimethylsiloxane in SC-CO2 system was studied by molecular simulation.Based on the binding energy,cohesive energy density and radial distribution function of solvent-solvent and solvent-solute,the solubilization effect of polar cosolvent and non-polar cosolvent on polydimethylsiloxane in supercritical carbon dioxide fracturing fluid system was compared and analyzed.The molecular simulation results show that the solubility parameter difference between methanol and solvent system is less than 0.5 at the same cosolvent content,and the solubilization effect is better than that of toluene and cyclohexane.The conclusion is that the essence of using cosolvent to improve the solubility of PDMS in SC-CO2 is the balance of the intermolecular force between CO2 and PDMS polymer,the intermolecular force between CO2 and cosolvent,and the intermolecular force between PDMS polymer and cosolvent.Therefore,when the siloxane tackifier itself is a non-polar material,toluene is recommended as a cosolvent.When the siloxane material has a certain weak polarity,methanol is the most suitable.关键词
超临界CO2压裂液/PDMS/分子模拟/溶解性/黏度Key words
SC-CO2 fracturing fluid/PDMS/Molecular simulation/Cosolvent/Viscosities分类
能源科技引用本文复制引用
陈雨飞,吴通,张辉,李军,周英操,张更..分子模拟助溶剂在硅氧烷类SC-CO2压裂液中的助溶行为研究[J].钻井液与完井液,2023,40(5):670-677,8.基金项目
国家自然基金科学基金资助项目"海相深层油气富集机理与关键工程技术基础研究"(19B6003). （19B6003）
