Characteristics and Breaking Conditions of Water-In-Oil Emulsions Based on Crude Oil from the Tailakovskoye Oil Field

The physicochemical properties and group composition of crude oil from the Tailakovskoye oil field were examined. As the temperature was lowered from 50 to 10°C, the structural and mechanical properties of the 20, 40, 60, and 70% water-in-oil emulsions (WOEs) of this oil were characterized and investigated. The mean molecular weights and spectral characteristics were evaluated for the resins and asphaltenes isolated both from the crude oil under study and from the stabilizing layers of the emulsions. The average molecule of the stabilizing layer asphaltenes was found to have a higher molecular weight than that of the parent oil asphaltenes. It was further shown that the WOE viscosity abruptly increases with rising water cut, especially at low temperatures: at 10°C the viscosity of the 70% WOE exceeded that of the parent crude oil by a factor of over 50. This is associated with the strengthening of the protective interfacial films surrounding water droplets. The emulsion stabilizers were found to mainly consist of asphaltenes. IR spectroscopy showed that the asphaltenes isolated from the stabilizing layer had a greater content of condensed and aliphatic moieties than the resins and asphaltenes from the parent crude oil. Finally, the effect of ultrasonic treatment on the dispersion of the WOEs was investigated for different water contents. The greatest sonication effect was observed for the WOEs with high water cuts.