(713h) Understanding Light Oil – Rock Interactions Using Molecular Dynamics

In enhanced oil recovery, the extraction efficiency of injecting fluids (IFL) heavily relies on the adsorption behavior of crude oil on the rock surfaces. Therefore, a detailed understanding of oil-rock interactions is crucial when designing efficient IFL for crude oil extraction. In this study, we performed molecular dynamics simulations to probe the structure and energetics of light oil (dodecane) near the carbonate (calcite), clay-type (mica), and sandstone (silica) reservoir surfaces. We found several layers of light oil adjacent to each rock surface with an additional bound layer on the calcite surface. We observed that the light oil molecules preferentially adsorbed parallel to the surface, with epitaxial adsorption over the calcium ions of the calcite surface, whereas structured adsorption was observed over oxygen atoms and silicate chains of the mica and silica surfaces, respectively. The adsorption strength, determining the presence or absence of the bound layer, was primarily governed by the strong net-interaction energy between the rock surface and oil, which was dominated by van der Waals interactions. In contrast, the distinctive adsorption pattern observed on each rock surface is attributed to local, atomic-level electrostatic interactions. Based on our comprehensive analysis, we provided a few recommendations for the IFL design.