Effect of Oil-Displacing Agent Composition on Oil/Water InterfaceStability of the Asphaltene-Rich ASP Flooding-Produced Water

In this work, the effect of oil-displacing agent composition on oil/water interface stability of the asphaltene-rich alkali-surfactant-polymer (ASP)flooding-produced water was systematically investigated, especially from theperspective of the interaction between oil displacement agents and asphaltene atthe oil/water interface. Primarily, adsorption behavior of the artificial and naturalinterfacial substances (oil displacement surfactant and asphaltenes) on the oil/water interface was investigated by molecular dynamics simulation. The oildisplacement surfactant and asphaltenes formed a cross-linked and compactinterfacialfilm structure, which significantly enhanced the interface stability; themore the oil displacement surfactants adsorbed on the interface, the more stable isthe cross-linked structure formed between them and asphaltenes. Then, theinterfacial property variations that are originating from the interactions differencesbetween oil displacement agents and asphaltenes were monitored via interfacialtension, zeta potential, and interfacialfilm rheology tests. Moreover, the effect ofoil displacement agent concentrations on the interfacialfilm thinning and rupture kinetic behavior was further investigated. Finally,cream experiments were conducted to verify the effect of oil displacement agent composition on the oil/water separation efficienciesof asphaltene-rich ASPflooding-produced water. When 5% asphaltenes was added, the creaming oil removal rate reduced from 90.0to 85.3% at 19 h. The interactions between asphaltenes and oil displacement agents immensely enhance the oil/water interfacialfilmstrength and impede the oil/water separation process

Automated summary

The effect of oil-displacing agent composition on the oil/water interface stability of asphaltene-rich ASP flooding-produced water was investigated. Molecular dynamics simulation and experimental tests were conducted to study the adsorption behavior of oil displacement agents and asphaltenes on the interface, as well as the variations in interfacial properties. The results showed that the interaction between oil displacement agents and asphaltenes enhanced the interfacial film strength and impeded the oil/water separation process.