Experimental Study On In-situ Self-emulsification Of Heavy Oil For Enhanced Oil Recovery

Some oil fields in China have entered a high water cut period,The development of the petroleum industry is in urgent need of improving the recovery technology,Chemical flooding is one of the most widely used methods for enhanced oil recovery,However,the world's crude oil prices have declined in recent years,The cost of chemical flooding technology has become increasingly apparent.It is the key to the development of petroleum industry that low cost and high efficiency improve recovery technology.In-situ emulsion flooding enhanced recovery technology has great potential in reducing oil production costs and improving oil recovery.The development of this technology is conducive to the development of the petroleum industry in today's situation.J reservoir in Xinjiang oilfield is a typical heavy oil reservoir,This paper takes it as the research background,The mechanism and efficiency of the In-situ emulsion flooding were studied in this paper.A large number of experimental studies on static evaluation of reservoir fluids show that the crude oil of J oil reservoir in Xinjiang oil field contains a large amount of gum.Stratum crude oil belongs to non-Newtonian fluid,the viscosity of crude oil decreases with the shear rate and temperature.The formation water contains high concentration of chloride ion and is weak alkaline.The type of emulsion formed by the formation of crude oil and injected water is W/O,Emulsion viscosity increases first and then decreases with increasing oil-water ratio,When the ratio of oil to water is 1:2,the viscosity of the emulsion reaches 6428 mPa s,Crude oil and injection water can be quickly emulsified,Crude oil and injected water can be quickly emulsified to form stable emulsion,this property of the emulsion contributes to enhanced oil recovery.The experiment of physical simulation shows that the optimum injection speed of water flooding and emulsion flooding is 0.8m/d.The ultimate recovery rate increases first and then decreases as the water drive time increases and Shows the same trend as the permeability increases.When the gas permeability is 500mD,the oil displacement efficiency is the highest.When using the best production method to physically simulate the flooding experiment,the ultimate recovery rate of the artificial core is as high as 61.14%,the oil displacement efficiency increased by 37.314%.Under the heterogeneous condition,the higher the permeability difference is,the lower the oil displacement efficiency is.The effect of emulsion injection timing on the ultimate recovery of emulsion flooding is not obvious.In general,the earlier the emulsion is flooded,the better the recovery effect is.Using the best injection method to physically simulate the recovery of emulsion flooding under heterogeneous conditions,the recovery rate can reach as high as 55.94%,and the recovery factor can be increased by 37.46%.Through the relewant experimental study of Emulsion flooding enhances oil recovery,It can provide a certain theoretical reference for the efficient development of heavy oil in thinking and methods.