稠油油藏冷采降黏复合驱油体系研究及应用OA

To address the low waterflooding efficiency in heavy oil reservoirs of Henan Oilfield,which arises from high crude oil viscosity and a large water-oil mobility ratio,macro-and micro-scale oil displacement experiments were conducted combined with the characteristics of heavy oil reservoirs in Block W,focusing on the development of a cold-production viscosity-reducing composite oil displacement system.The results indicate that compounding an emulsifying viscosity reducer with a polymer yields a new cold-production viscosity-reducing composite oil displacement system(0.3%H1 viscosity reducer+0.1%ZL polymer)capable of"regulating the viscosity of both oil and water phases".Under the conditions of an oil-water ratio of 5:5 and 50℃,this composite system significantly reduces the oil-water viscosity ratio to 2.02,achieving an emulsifying viscosity reduction rate of up to 97.77%for heavy oil.Additionally,the mechanism by which the composite system microscopically activates residual oil and its oil recovery enhancement effect have been clarified:through the synergistic action of its inherent viscoelasticity and emulsifying viscosity-reducing properties,it effectively mobilizes residual oil in blind-end,thin-film,and adsorbed forms.Compared with water flooding,it increases oil recovery by 40.35%and reduces water cut by 59.5%.Field tests in Well Group 3 of Block W have all demonstrated favorable water cut reduction and oil increment effects,further confirming the broad application prospects of this composite oil displacement system.