Abstract

To clarify the mechanism responsible for the reduction of interfacial tension (IFT), the dynamic and equilibrium IFTs of different betaine solutions against n-alkanes, kerosene, heavy oil fractions model oil and crude oil have been investigated by spinning-drop interfacial tensiometer. The experimental results show that the synergism for lowering IFT between heavy crude oil and betaine solutions are controlled by two main factors. One is “size compatibility” between surfactant molecules and surface-active substances in crude oil. The other is the optimized ratio of crude oil fraction to betaine. The betaine molecules with large size of hydrophilic group can form compact interfacial film with surface-active fractions in heavy crude oil by mixed adsorption. Therefore, betaines with large hydrophilic groups show an apparent synergism with heavy crude oil in lowering IFT and can produce ultralow IFT value at optimized concentration.

摘要

为了阐明降低界面张力 (IFT) 的机制，采用旋滴界面张力计研究了不同甜菜碱溶液对正构烷烃、煤油、重油馏分模型油和原油的动态和平衡界面张力。实验结果表明，重质原油和甜菜碱溶液之间降低 IFT 的协同作用受两个主要因素控制。一是表面活性剂分子与原油中表面活性物质之间的“尺寸相容性”。二是原油馏分与甜菜碱的优化配比。具有大亲水基团的甜菜碱分子可以通过混合吸附与稠油中的表面活性馏分形成致密的界面膜。所以，