Preparation and application property of viscosity reducer with nano-sized KH550-C18/SiO₂ composite particles for heavy oil

A novel nano-silica composite particle viscosity reducer for heavy oil was prepared by modifying the surface of nano-silica with silane couping agent KH550 and stearic acid. The structure and property of modified nano-silica particles were characterized and analyzed by FTIR, TG, TEM and DSC. Its viscosity reducing effect for high-wax heavy oil in Daqing oilfield was studied, and the effects on viscosity reducing were investigated by the ratio of modifier and dosage of viscosity reducer. After surface modification, the nano-silica composite particles were low agglomerated and could be dispersed in organic medium stably. Because the nano-sized KH550-C18/SiO₂ composite particles were surface grafted with organic long chain containing polar group, they could change wax's crystallization behavior and prevent colloid and asphaltene forming large-sized aggregate. Under the optimal synthesis conditions and the best addition, its apparent viscosity reducing ratio and pure viscosity reducing ratio reached 66.91% and 40.32% respectively at 40 ℃, which is better than the commercial viscosity reducer EVA.