Determent of oil-soluble surfactants on aggregation of model asphaltene compound and synergistic effect of their mixtures on foaming property

Oil-based foam stabilized by dispersed asphaltene is potential in the oil recovery process of water-sensitive formations. But asphaltenes are prone to aggregate, which jeopardizes the stability of the foam. This paper investigated the effect of different VO79 (model asphaltene compound violanthrone-79) systems on the performance of oil-based foams through surface tension and foaming tests. And simulations were performed to investigate the microscopic mechanism of ODA (octadecyl amine) and Span20 (sorbitan monolaurate) on the dispersion effect of VO79 and the effect of their mixtures on the interfacial film formation. The experimental results showed that the mixed system of ODA, Span20, and VO79 significantly enhances the performance of the oil-based foam. According to simulative results, ODA and Span20 blending are able to form ODA: Span20 molecular pairs, inhibiting the aggregation of model asphaltenes. The blend of ODA, Span20, and VO79 tends to form a ternary supramolecular complex, assembling into a dense and stretchable interfacial film. The synergistic effect generated by the ternary blends is capable of optimizing the performance of oil-based foams.