Effect of pressure sensitivity on production rate in low permeability sandstone formation

This paper adopts a set of systematic experimental methods that simulate the overburden pressure,simulate the ways of pressurization for the originally state of reservoir,and ascertain the equilibrium time for physical properties after pressure to study the effect of pressure sensitivity on production rate in low permeability sandstone in laboratories.It aims to research the effect of pressure sensitivity on production rate in low-permeability sandstone formation based on simulating the pressure change in real oilfield production,comparing the different effect of rapid-changing effective pressure and slow-changing effective pressure on reservoir petrophysics,and analyzing the porosity of the physic parameters in low permeability formation and the changing law of permeability with the effective pressure as well as the characteristics of pressure sensitivity.The research shows that rocks permeability will see a dramatic decrease even if there is little loss in the porosity of low permeability formation,which is greatly influenced by the ways of pressurization.The more rapidly the speed pressure increases,the more the rate of core permeability reduces and the more the inconvertible permeability loses.Instead,the more slowly the speed pressure decreases,the less the rate of core permeability reduces and the less the inconvertible permeability loses.It is suggested that multi-stage sequential decrease of flowing bottom-hole pressure be employed and rational exploitation velocity be kept to increase ultimate recovery rate during developing low permeability oilfield.