基于Darcy-Stokes耦合模型的缝洞型介质等效渗透率分析

根据缝洞型介质的特点和流体在不同尺度空间的流动特征,建立Darcy-Stokes耦合数学模型,推导出考虑基岩渗透率的广义立方定律和单裂缝多孔介质的等效渗透率张量表达式,以此为基础提出裂缝预处理技术,将溶洞-裂缝-基岩耦合流动问题转化为溶洞-基岩耦合流动问题,分析不同缝洞结构介质体的等效渗透率和渗透特性。结果表明:缝洞结构的存在不同程度地影响介质体的等效渗透率;含圆形溶洞介质的等效渗透率与基岩渗透率成线性关系;裂缝预处理技术可以提高计算效率。

Estimating equivalent permeability of fractured-vuggy media based on coupled Darcy-Stokes model

A coupled Darcy-Stokes model was developed to estimate equivalent permeability(EP) of fractured-vuggy media(FVM) according to the structure property of FVM and the fluid flow characteristics in different-scale voids.The generalized cubic law considering bedrock permeability and equivalent permeability tensor of single-fractured porous media were derived.The pretreatment technique of fractured porous media(FPM) was developed.Thus the vug-fracture-matrix coupled flow problem was converted into the vug-matrix problem.The equivalent permeability and permeability characteristics of different FVMs were analyzed.The results show that the EP of FVM was affected by the existence of fractures and vugs in various degrees.The EP of porous media with single circle vug is linear with the matrix permeability.The pretreatment technique of FPM can enhance the computation efficiency.