COMPARISON OF FIELD-SCALE EFFECTIVE PROPERTIES OF TWO-PHASE FLOW IN HETEROGENEOUS POROUS MEDIA OBTAINED BY STOCHASTIC ANALYSIS AND NUMERICAL EXPERIMENTS

摘要

The field-scale effective relative permeability and capillary pressure function (with respect to mean saturation) of two-phase flow were obtained for a heterogeneous system with properties representing the Borden Aquifer, using numerical and stochastic analysis. The vertical effective relative permeability is significantly lower than the homogeneous one found using mean capillary parameters, particularly at low mean DNAPL saturation (low mean capillary pressure). The significant difference is mainly due to the large variance of actual DNAPL permeability (combination of intrinsic permeability and its positively correlated relative permeability). On the other hand, the effective capillary pressure function differs only slightly from the homogeneous case. This deviation results from the small variance of capillary pressure, which is smaller than that of the characteristic capillary pressure. By comparison, the effective properties of two-phase flow obtained by the numerical simulation and stochastic analysis are in good agreement. The numerical analysis can be used for any highly heterogeneous formations, whereas the stochastic analysis can give us insight into the internal correlations between output and input variability in mildly heterogeneous systems.