基于非均匀渗透率和气水相渗时变的超深层裂缝性致密砂岩气藏数值模拟方法OA

Application of conventional numerical simulation methods to ultra-deep fractured tight sandstone gas reservoirs fails to consider the impact of the spatial heterogeneity of reservoir properties(e.g.porosity)on permeability reduction and the time-dependent effect of gas–water relative permeability during development,thereby impeding the accuracy of productivity and water breakthrough forecast.For ultra-deep fractured gas reservoirs with water presence,this paper investigates the correlation between matrix/fracture permeability variation and reservoir properties,and the changes in gas–water flow capacity during water invasion,by considering the time-dependent variations of heterogeneous matrix/fracture permeability and gas–water relative permeability.Then,a time-dependent numerical simulation method for ultra-deep fractured tight sandstone gas reservoirs is developed based on a projection-based embedded discrete fracture model(pEDFM).The following results are obtained.First,when the heterogeneous permeability variation in the matrix and fractures is considered,the overall permeability exhibits a smaller heterogeneous reduction than homogeneous reduction in conventional simulation.Second,the numerical simulation yields higher daily and cumulative gas productions compared to the case with homogeneous permeability variation,reflecting the extent to which how the heterogeneous reduction of matrix/fracture permeability is more reasonable.Third,the numerical simulation incorporating time-dependent gas–water relative permeability indicates that edge water invades more prominently along fractures,and accelerates its breakthrough toward production wells,leading to premature water breakthrough,shorter stable production period,and lower gas production.It is concluded that the proposed numerical simulation method considering heterogeneous permeability and time-dependent gas–water relative permeability matches field history more accurately,confirming its reliability and practical value.This research insight offers a robust theoretical and technical foundation for enhancing the development efficiency of ultra-deep fractured tight sandstone gas reservoirs.