Effect of Reaction of NaOH and Daqing Crude Oil on Oil/Water Interfacial Properties and Emulsion Stability

The oil/water interfacial properties and the stability of the emulsion of ASP flooding in Daqing Oilfield were investigated with the measurement of interfacial tension, interfacial shear viscosity,Zeta potential and turbidity of the oil/water system. The results show that, after NaOH has reacted with Daqing crude oil for a long time, the interfacial tension between the aqueous phase and Daqing model oil decreases. The absolute value of the Zeta potential of the surface of oil droplets increases. The changes of the interfacial shear viscosity between the aqueous phase and the oil phase do not appear to be obvious. The stability of O/W emulsion formed by Daqing model oil and the aqueous phase is enhanced. After NaOH has reacted with crude oil for 1d, the interfacial tension between oil phase and simulated water, Zeta potential and the stability of the oil/water emulsion become higher than that of the emulsion without NaOH. However, after NaOH has reacted with crude oil for 10 d and 30 d, respectively, the interfacial tension between oil phase and simulated water, Zeta potential and the stability of the O/W emulsion are lower than that of the emulsion with the same reaction for 1d.