Synergetic Water Control Technique Combining Relative Permeability Modification And Inflow Control

Water production is a common phenomenon at the middle and last development stages of oil reservoirs.Due to the oil layer heterogeneity and improper yielding measure,water unevenly propelles along the large pores of high permeability layer and fractures,which lead to a sharp increase of water content and a decrease of oil recovery index.The horizontal wells have advantages of higher oil recovery index,smaller differential pressure of production and longer water-free oil production period.However,when water breakthrough,the water content will rise and oil production decrease sharply.In this paper,a synergistic water control technology by using relative permeability modifier(RPM)and flow controlling technologies was proposed to postpon the water breakthrough time,enhance the water controlling effect of mechanical water control technologies such as base pipe and Inflow Control Device(ICD)by changing relative permeability near the wellbore and changing the oil-water ratio of the fluid which flows into the wellbore.In this paper,based on the physical parameters of oil reservoir in Xinjiang Luliang oil field,single-phase core fluxion experiment and unsteady(constant velocity)method were used in the tests.Kinds of RPMs(Anionic polymer,Polymer,Weak gel,etc.)were prepared and optimized,the injection parameters(injection volume and injection concentration)were determined;on this basis,the Eclipse numerical simulator was used to simulate the synergetic effect of RPM and flow controlling technologies.The test results showed that RPM had a strong selective effect for both oil and water,of which HPAM weak gel performed well.It can reduce the relative permeability of water by 65%on average and reduce the relative permeability of oil within 15%on average.HPAM weak gel can reduce relative permeability of water by 80.07%and reduce relative permeability of oil by19.92%at the injection concentration of 0.35%and injection volume of 0.5PV.The numerical simulation results showed a better effect when combined RPM with ICD or base pipe techonologies in high permeability strip of horizontal well,and the base pipe technology performed better than ICD technology.With the application of base pipe and RPM,the water content fell by 11.72%at 60%water content,and cumulative oil production rose 5.37×10~3m~3after 3600 days.From the view of injection parameters,earlier injection of RPM resulted in a better effect,but the effective time and cost should be considered.In high permeability strip of horizontal well,the injection depth should not be too deep.