Simulation of NAPL vertical infiltration in a heterogeneous soil

Simulation of NAPL vertical infiltration in a heterogeneous soil

Chetverushkin, B.N.
Churbanova, N.G.
Isupov, N.V.
Trapeznikova, M.A.

2006-09-06

The research deals with simulation of contaminant infiltration and spreading in soils. The problem has substantial ecological sense to predict possible contamination of the soil air and the groundwater. As contaminants, for example, mineral fuels, solvents and detergents (in other words Non-Aqueous Phase Liquids - NAPLs) can be considered. These liquids are immiscible with gas and water therefore one has to treat multiphase flows. The governing model takes into account capillary and gravity forces and includes some capillary pressure - saturation relation [1, 2]. There are Light and Dense NAPLs depending on the relation of their density to the water density. A number of test problems were solved. Tests concerning the DNAPL (tetrachloroethylene) infiltration into a fully saturated reservoir and the LNAPL (oil) infiltration into an unsaturated reservoir require the two-phase problem statement. Numerical implementations are based on the finite differences with consequent solution by the IMPES method. All the problems are treated in the 2D vertical section. It is assumed that porous media are heterogeneous, i.e. they consist of layers with different porosities and permeabilities or contain low permeability lenses. The special transition conditions are used at the interface of heterogeneity to ensure physically correct solutions. The applied problem that will be further under consideration is connected with the petrol infiltration from the earth surface into the relatively dry ground until reaching the water table. Realistic data obtaining by measuring in the locality will be used. Investigation of the oil-products propagation is of great practical importance due to the potential danger of drinking water contamination. In this case the three-phase flow has to be considered. Software tools developed and tested up to the present time will be implemented for solving such kind of ecological problems. Another aim for the future is to develop an efficient fully implicit algorithm to avoid strong time-step restrictions.

multiphase flow
Light and Dense Non-Aqueous Phase Liquids
infiltration
Heterogeneous Porous Media

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Conference proceedings

conference paper

(c) 2006 Chetverushkin, B.N.; Churbanova, N.G.; Isupov, N.V.; Trapeznikova, M.A.