Abstract: Stability dynamic characteristics of alkali/surfactant/polymer(ASP) flooding crude oil emulsion was studied using emulsion stability model based on two-phase separation. Effect of alkali/surfactant/polymer on dynamic characteristics of ASP flooding crude oil emulsion was also studied by analyzing oil film strength qualitatively and measuring oil-water interfacial tension. The results showed that Civan model was suitable to evaluate the stability of ASP flooding crude oil emulsion and thus the stability dynamic characteristics were obtained. The crude oil emulsions became more stable with the increase of alkali concentration firstly at low alkali concentration(＜900 mg/L) and then less stable with the increasing alkali concentration at high alkali concentration(＞900 mg/L). The stabilities of crude oil emulsions were improved with the increase of the concentrations of surfactant and polymer. The stability mechanism of ASP flooding W/O emulsion could be ascribed to the decrease of oil-water interfacial tensions when alkali and surfactant were used and increase of the oil-water interfacial strength when the polymer was added to the system. Therefore alkali, surfactant and polymer have synergistic effect.

Key words: ASP flooding, crude oil emulsion, dynamic characteristics, interfacial tension, oil film strength, stability