Experimental Studies On Viscosity Reduction Of Heavy Oil-water System By Sonochemical Treatment

Viscosity reduction is one of the key issues for heavy oil reservoir development and heavy oil transportation. The sonochemical mehtod is a new method for viscosity reduction, which combines ultrasonic method with chemical method to decrease the viscosity of heavy oil greatly. Up to now, the mechanisms for sonochemical viscosity reduction are not clear, especially for heavy oil-water system and need to be studied urgently.The viscosity was measured by Brookfield DV-III Ultra Programmable Rheometer. The effect of ultrasonic treatment, chemical treatment and sonochemical treatment on the viscosity of dewatered heavy oil and heavy oil-water system was studied. The influence of ultrasonic power, treating time, temperature, water cut,shear rate and the concentration of chemicals on viscosity reduction of heavy oil and heavy oil-water system were analyzed by orthogonal tests. The parameters for viscosity reduction were optimized to achieve the excellent result of viscosity reduction. The comparisons of viscosity reduction between ultrasonic treatment, chemical method and sonochemical method were carried out.Experiments show that ultrasonic treatment can reduce the viscosity of heavy oil and heavy oil-water system greatly and the viscosity reduction rate can reach 90%. The viscosity reduction rate increases with the increase of ultrasonic power and treating time. As for the heavy oil, the parameters influencing viscosity reduction by ultrasonic treatment are in the order of treating time, ultrasonic power and temperature. As for the heavy oil-water system, the parameters influencing viscosity reduction are in the order of ultrasonic power, treating time, water-cut and temperature. Sonochemical method is the best for viscosity reduction than ultrasonic treatment and chemical method used separately. This proves the existence of synergistic effect between ultrasonic treatment and chemical agent. The concentration of chemical agent can be reduced by 50% when sonochemical method is used to achieve the same result.