Study On Oil And Water Interferential Pressure Gradient And Characterization Method Of Inefficient Water-flooding

For decades,in the development of domestic continental sandstone oil fields,the traditional theory of fluid transport in porous media based on Darcy’s law have made great contributions.However,in the high water cut stage,there is obvious adaptability of the traditional theory of fluid transport in porous media.Including there is large prediction error of development index,such as water flooding characteristic curve,the calculated interlayer interferential factor is far less than the actual results,and it unable to describe the phenomenon of no water absorption for low permeability layer.Therefore,there would cause great deviation if traditional theory continue applied in high water cut stage.The development of oilfield couldn’t be conducted correctly until revealing the mechanism of inadaptability and improving the corresponding porous flow mathematical model.Via the microcosmic numerical simulation,this paper presented the oil and water twophase flow in the pore scale.By analyzing the inadaptability of traditional theory,the oil and water interferential pressure gradients are presented to improve the corresponding mathematical model of fluid transport in porous media.At the same time,the phase field method and physical experiments are employed to verify the existence and rationality of oil and water interferential pressure gradient.Then,a large number of porous media models with different physical properties are constructed,and the corresponding oil-water interferential pressure gradients are simulated.By discussing the relationship between two-phase interferential pressure gradient and rock physical parameters,the characterization model of two-phase interferential pressure gradient are established.Afterward,this paper compiled the new numerical simulator considering the mechanism of two-phase interferential pressure gradient,by embedding the two-phase interferential pressure gradient characterization model into the mathematical model of fluid transport in porous media.On the basis of the new numerical simulator,the remaining oil characteristics,water flooding characteristics and interferential characteristics are analyzed.Finally,this paper used the improved numerical simulator to study the characterization method of inefficient water-flooding zone,which realizes the accurate and rapid identification of the inefficient water-flooding zone.Results show that the simulation results considering the mechanism of two-phase interferential pressure gradient are closer to the actual situation of oilfield.The different hierarchical inefficiency water-flooding zone can be recognized by the identification method.