Asphaltene Aggregation and Assembly Behaviors in Organic Solvents with Water and Inhibitor

Asphaltenes cause problems such as emulsion formation and deposition/precipitation during crude oil production, processing, and transport. A deeper understanding of the behaviors of asphaltenes is needed to design remediation treatments to minimize costs during production. In this study, the aggregation and assembly behaviors of asphaltene model compound CSPeC11 under different conditions were studied and visualized through molecular dynamic simulations. CSPeC11 aggregates were formed as a result of the competition between the solvation of CSPeC11 in solvents and the self-association of CSPeC11 molecules. One-dimensional bent linear assembly of CSPeC11 aggregates was observed upon the addition of n-heptane to toluene. Although the water content was low, the addition of water molecules resulted in enhanced CSPeC11 aggregation and considerably different C5PeC11 aggregate assembly behaviors. CSPeC11 aggregates formed a cluster in a parallel horizontal connection manner with the hydrocarbon tails located outside and polar groups located inside. The network formed via the hydrogen bonding between CSPeC11 and water as well as between water molecules provided new binding interactions for CSPeC11 aggregates. Water molecules were indispensable for the formation and retention of a CSPeC11 aggregate cluster. Dodecylbenzene sulfonic acid (DBSA) and water competed with each other to influence asphaltene associations when they were both present in the system. Both the hydrogen bonding between CSPeC11 and water and hydrogen bonding between water molecules contributing to the development of the network were hindered by DBSA. DBSA molecules succeeded in stabilizing C5PeC11 even in the presence of water molecules.