Study on the stability of emulsion based on molecular dynamics

Emulsion stability directly affects the effect of surfactants in driving oil production. In this paper, the influence of crude oil components and the molecular structure of surfactants on the stability of emulsions is studied. First, emulsion samples with different asphaltene contents are prepared and passed. The emulsion time strength stability was characterized, and its mechanism of action was analyzed by molecular simulation methods. It was found that asphaltenes directly affect the strength of the oil-water interface membrane. The higher the asphaltene content, the stronger the emulsion stability. Then the emulsion containing different molecular structure surfactants was prepared, it was found that the more unstable bonds on the hydrophilic groups of nonionic surfactants, the weaker the strength of the interfacial membrane, and the worse the stability of the emulsion, and the cationic surfactants. The binding ability of different hydrophilic group ions to water molecules is different, and the thickness of the water adsorption layer is different. The order of the binding ability of ions to water is: K+ > Na+ > NH4+.