STOCHASTIC-ANALYSIS OF 2-PHASE FLOW IN POROUS-MEDIA .1. SPECTRAL PERTURBATION APPROACH

Stochastic analysis of steady-state two-phase (water and oil) flow in heterogeneous porous media is performed using the perturbation theory and spectral representation techniques. The governing equations descri bing the flow are coupled and nonlinear. The key stochastic input vari ables are intrinsic permeability, kappa, and the soil and fluid depend ent retention parameter, Gamma. Three different stochastic combination s of these two imput parameters were considered. The perturbation/spec tral analysis was used to develop closed-form expressions that describ e stochastic variability of key output processes, such as capillary an d individual phase pressures and specific discharges. The analysis als o included the estimation of the effective flow properties. The impact of the spatial variability of kappa and Gamma on the variances of pre ssures, effective conductivities, and specific discharges was examined .