Characterizing the behavior of asphaltenes at the water-decane interface: a Molecular Dynamics simulation approach

Abstract

Asphaltenes play a crucial role in the behavior of heavy crudes due to their propensity for aggregation, precipitation, and adsorption at various interfaces and surfaces. This behavior is especially significant in flow assurance, as it reduces rock permeability in reservoirs and decreases pipe diameter during transportation. Additionally, asphaltenes are known to stabilize water-in-oil (and oil-in-water) emulsions. Numerous experimental and computational studies have been conducted to investigate their behavior, but challenges arise due to variations in weight and molecular structure. In this study, molecular dynamics (MD) simulations were employed to evaluate the interfacial behavior of an asphaltene model compound (C5PeC11), considering the influence of the initial position of asphaltenes on surface pressure results compared to experimental data, as well as their behavior in adsorption at the water-decane interface and the interactions they exhibit. The MD simulations revealed that randomly inserting the asphaltene model compound provided a valuable tool for studying and characterizing natural asphaltenes. Results from the model asphaltene simulations closely reproduced experimental findings when utilizing an ordered initial insertion. Additionally, a notable energy barrier was observed in the region close to the liquid-condensed phase, which could be overcome by supplying energy to the system. This study enhances our understanding of asphaltene behavior at the water-decane interface and sheds light on their influence in the oil industry