Study On Viscosity Reduction Of The Sulfonate Complex System In Heavy Oil Reservoir

Heavy oilcomprises a significant proportion of crude oil reserves in the world. Heavy oil resources are also very rich in China, and there are nearly 200 million tons remain unexploited in Shengli Oilfield. With the unusual properties of hyperviscosity and high pour point, it is hard to be developed and applicated.Steam drive and steam stimulation are applied most frequently in viscosity reduction of heavy oil. The early treatment effect is good, but its high energy consumption,and the high water cutstage influence subsequent heavy oil recovery. Surfactants occupies an important position in the oilfield chemicals, especially has broad application prospects as the viscosity reducer because of the capacity of reducing the interfacial tension between oil and water and promoting the emulsion and dispersion of crude oil. Petroleum sulfonate arouses the interest of research institutes both at home and abroad as a good surfactant, which focus on the usage as system of surfactant in improving recovery of heavy oil.In this paper,extraction separation is used to calibrate the activity component in petroleum sulfonate, and two kinds of additives named polyether sulfonate and polymer surfactant are selected. Through a series of compound viscosity reduction experiments, the formulation PS-480%/polyether sulfonate 20% is ultimately chosen.The mixed sulfonate system is evaluated systematically. It proves that the mixed sulfonate system can improve the steam displacement efficiency by 7%-15%,and can improve the simulation displacement efficiency of heterogeneous oil by 3%,but can not improve the degree of uniformity effectively.