Investigation on the mechanism of heating effect influencing emulsifying ability of crude oil: Experimental and molecular dynamics simulation

Abstract

Water flooding can create a transient heating effect that causes oil and water to self-emulsify. This study sought to understand how this effect impacts crude oil's emulsifying properties by conducting oil-water emulsification experiments and investigating the effects of initial temperature, heating rate, and effective time. Additionally, asphaltene dispersion, adsorption behavior, and viscoelasticity of crude oil and its interfacial components were analyzed to unravel the mechanism behind the heating effect on crude oil's emulsifying capacity. The heating effect was observed to suppress interaction force dissipation between asphaltene molecules effectively from low to high temperatures. This increased both the interfacial film thickness and steric hindrance, improving crude oil's emulsifying ability. However, at high temperatures, the interfacial film became unstable, which led to the normalization of crude oil's emulsifying ability after the effective time. These findings provide insight into the emulsifying mechanisms of water-drive reservoirs and the in-situ emulsifying theory of underground crude oil.