Study of Asphaltene Deposition in the Presence of a Hydrophobic Deep Eutectic Solvent Using XDLVO Theory

This study aims to theoretically investigate the performance of an ionic liquid-based hydrophobic deep eutectic solvent (HDES), methyltrioctylammonium chloride:glycerol (1:2), as an asphaltene deposition inhibitor. To do so, the concept of surface energy was implemented by applying the extended DLVO (Derjaguin–Landau–Verwey–Overbeek) theory. Accordingly, the impact of surface energy components in terms of electrostatic (EL), acid–base (AB), Lifshitz–van der Waals (LW), and Brownian (Br) interactions on the deposition process has been examined. In addition, the works of cohesion and adhesion between different interacting bodies involved in the deposition process have been determined. The results revealed that AB interactions played an essential role in the inhibition of asphaltene deposition by reducing the propensity of asphaltene toward the dolomite surface. The total interaction energy also showed that the presence of HDES would take the interaction energy of asphaltene-dolomite from attraction toward the repulsive state as much as 125%. Furthermore, the calculated works of cohesion/adhesion proved that the addition of HDES to the model oil could retard asphaltene particles’ cohesion, thus preventing them from aggregation and subsequent deposition onto the dolomite surface. It was also shown that HDES, dissolved in the model oil, would primarily be attracted by asphaltene rather than its own molecules, hence producing HDES-asphaltene conjugates in the medium. Finally, the lower affinity of asphaltenes toward the dolomite surface in the presence of HDES was confirmed using the work of adhesion. The theoretical approach, proposed in this study, can provide a guideline to evaluate the intermolecular interactions between interacting bodies during the asphaltene deposition process, including asphaltene, inhibitor, reservoir rock, and oleic medium.