SIMULATION OF ORGANIC LIQUID FLOW IN POROUS-MEDIA USING ESTIMATED ANDMEASURED TRANSPORT-PROPERTIES

Many numerical models which describe the movement of a separate organi c liquid phase in the subsurface require information about the relatio nships between capillary pressure and saturation, and between relative permeability and saturation. An evaluation of the information availab le for these relationships suggests that substantial discrepancies may be introduced into simulations if estimated, rather than measured, da ta are employed. The purpose of this study was to quantify these devia tions. Two-phase displacement simulations were performed in one and tw o dimensions for several organic liquid-water systems. Both constant-h ead and constant-flux boundary conditions were employed at a variety o f flow rates and time scales, using both measurements and estimates of capillary pressure and relative permeability for a sandy aquifer mate rial. The results demonstrate that the use of estimated transport rela tionships produces significantly different predictions of organic liqu id migration. The magnitude of the deviations between predictions may be as high as 25% or more after relatively short displacement periods, depending on the boundary conditions of the simulated scenario, as we ll as on the physical characteristics of the two-phase system. For the systems examined, most of the deviations resulted from the estimates for relative permeability to the organic liquid. Thus, improved method s for the estimation of the relative permeability to the organic liqui d are needed to reduce the uncertainty in displacement simulations.