Relevance between Emulsification Capability and Interfacial Tension of Chemical Flooding Agents

Abstract

In chemical flooding processes, in situ emulsification between oil displacing agents and crude oil has a significant effect on enhanced oil recovery. Currently, this in situ emulsification process is still little understood. Aiming at this problem, we devised a novel experimental parameter (emulsification index) for better emulsification characterization (i.e., quantification of emulsification capability) and used this parameter to investigate the effect of crude oil–water interfacial tension (IFT) on the emulsification capability of three typical surfactant types. From comprehensive analysis of 111 experimental test results, we found that there was a critical IFT (σc) in the range of IFT level 10–4 to 101 mN/m in which the emulsification index and IFT went from no correlation to that of inverse log correlation. This critical IFT varies with the composition of crude oil and water. During oil displacement experiments, experimental observation of the emulsification process not only confirmed the aforementioned complex phenomenon between the emulsification capability and IFT but also demonstrated that the emulsification index was an effective parameter characterizing emulsification capability in a crude oil–water system during displacement process.