Article ID Journal Published Year Pages File Type
4525478 Advances in Water Resources 2014 13 Pages PDF
Abstract

•A computational model for leakage of fluid in layered porous media is introduced.•A mixed finite element scheme is utilized.•Discontinuous saturation–continuous pressure formulation is adopted.•The boundary between layers can be embedded within the finite elements.•The model allows the use of structured, geometry-independent and coarse meshes.

This paper introduces a new and computationally efficient model for the simulation of non-wetting phase leakage in a rigid heterogeneous layered medium domain constituting layers of different physical properties. Such a leakage exhibits a discontinuity in the saturation field at the interface between layers. The governing field equations are derived based on the averaging theory and solved numerically using a mixed finite element discretization scheme. This scheme entails solving different balance equations using different discretization techniques, which are tailored to accurately simulate the physical behavior of the primary state variables. A discontinuous non-wetting phase saturation–continuous water pressure formulation is adopted. The standard Galerkin finite element method is utilized to discretize the water phase pressure field, and the partition of unity finite element method is utilized to discretize the non-wetting phase saturation field. This mixed discretization scheme leads to a locally conservative system, giving accurate simulation of the saturation jump. The boundary between layers is embedded within the finite elements, alleviating the need to use the typical interface elements, and allowing for the use of structured, geometry-independent and relatively coarse meshes. The accuracy and capability of the proposed model are evaluated by verification and numerical examples covering water, DNAPL and CO2 leakage through layers of different hydraulic properties.

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Related Topics
Physical Sciences and Engineering Earth and Planetary Sciences Earth-Surface Processes
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