长链烷基甜菜碱表面活性剂在驱油用油水界面行为的分子模拟研究

Molecular simulation study on the behavior of long-alkyl-chain betaine surfactants at the interface between water and the oil

随着化学驱规模化实施,表面活性剂的需求量猛增,而甜菜碱型表面活性剂由于其优异的界面活性、抗盐性能及绿色环保等特点,是适合油田多场景开采的一类高效驱油剂。为从分子尺度探究长链烷基甜菜碱型表面活性剂的界面活性并解释提采机制,利用分子动力学模拟研究了不同疏水链长和亲水基团的甜菜碱型表面活性剂油水界面行为和微观分子构型。通过与实验数据相互验证,为宏观实验现象提供了微观分子层面解释,并归纳了长链烷基甜菜碱型表面活性剂的界面作用机制,为根据分子模拟界面迁移及分布规律进行驱油剂设计提供指导。

With the large-scale implementation of chemical flooding,the demand for surfactants has increased sharply.Betaine surfactants are a type of efficient displacement agent suitable for multi-scenario exploitation in oilfields due to their excellent interfacial activity,salt resistance,and environmental friendliness.Molecular dynamics simulations were used to study the oil-water interface behavior and microscopic molecular configuration of betaine surfactants with different hydrophobic chain lengths and hydrophilic groups,so as to explore the interfacial activity of long-alkyl-chain betaine surfactants at the molecular level,and explain the recovery-enhancing mechanism.Through mutual verification between the simulation results and experimental data,microscopic explanations for macroscopic experimental phenomena were provided.Furthermore,the interfacial action mechanism of long-alkyl-chain betaine surfactants was summarized,providing guidance for the design of displacement agents based on the interface migration and distribution by molecular simulation.