Coupling of a two phase gas liquid 3D Darcy flow in fractured porous media with a 1D free gas flow

摘要

A model coupling a three dimensional gas liquid compositional Darcy flow in a frac-tured porous medium, and a one dimensional compositional free gas flow is presented. The coupling conditions at the interface between the gallery and the porous medium account for the molar normal fluxes continuity for each component, the gas liquid thermody-namical equilibrium, the gas pressure continuity and the gas and liquid molar fractions continuity. The fractures are represented as interfaces of codimension one immersed in the surrounding 3D porous medium, the matrix. Pressure continuity is assumed for both phases at the interfaces between the fracture and the matrix. The spatial discretization is based on the Vertex Approximate Gradient (VAG) scheme in the porous medium coupled with a non conforming control volume finite element discretization in the gallery. This model is applied to the simulation of the mass exchanges at the interface between the repository and the ventilation excavated gallery in a nuclear waste geological repository.