LABORATORY AND NUMERICAL INVESTIGATIONS OF IMMISCIBLE MULTIPHASE FLOW IN SOIL

Immiscible multiphase flow in porous media is investigated by laboratory experiments and numerical simulations. The hydraulic parameters used in mathematical models for multiphase flow are determined experimentally, and the interrelations between the individual parameters are analysed. The experimental data support the applicability of analytical closed-form expressions for the constitutive relations, and a scaling procedure is verified in which the interfacial tensions are used to derive scaling factors. These simplifications in the parameter requirements are very valuable from an engineering point of view. A two-dimensional plexiglass flume is used for studying the flow of lighter-than-water, non-aqueous phase liquids (LNAPL) in sandy porous media, The migration of the LNAPL is observed both in the unsaturated zone and in the saturated zone at the bottom of the flume. A dual-gamma attenuation system is used for measuring the phase saturations of organic fluid, water, and air simultaneously without disturbing the flow. This permits a two-dimensional quantitative determination of the LNAPL plume in contrast to many earlier qualitative studies. A black oil reservoir model is used to simulate immiscible multiphase flow. By using the parameter estimation methods presented for establishing the constitutive relations, the model is applied to the simulation of the laboratory experiments. The experimental and numerical results compare reasonably well, thus supporting the adopted model formulation.