Development of a 3D Fem Simulator on Multiphase Seepage Flows and its Applications

Abstract

This paper introduces a 3D FEM simulator for multiphase flows in porous media and its applications through consecutive consulting projects in the past three years. Based on the three-dimensional finite element method for two-phase flow of a liquid (underground water) and an immiscible or partly soluble gas (air, methane, CO 2 , etc.) seepage flows in porous media, the corresponding partial differential simultaneous equations and their numerical discretization method as well as the sorption/diffusion formulations are described. The simulator has been mainly applied to simulate both the combustible gas and water flows induced by a step-wise excavation process in sedimentary rock for disaster prevention during underground excavation for nuclear waste disposal. Furthermore, the simulator has been applied to predict the coal mine gas and water flows induced by face advancement in coal mining. These practical application examples are given in this paper.

Pore-scale gas–water flow in rock: Visualization experiment and simulation

“…In recent years, with the improvement of pore-scale flow theories and computer performance, the numerical simulation of pore-scale flow in rock has developed rapidly [15][16][17][18][19]. At present, the commonly used simulation methods include the Lattice Boltzmann Method (hereafter referred to as "the LBM") [23][24][25][26][27] and the Navier-Stokes equation based numerical simulation method [28][29][30][31][32][33][34][35]. Both methods are based on the pore network characteristics and used to simulate the pore-scale fluid flow in rock.…”

“…By contrast, the numerical simulation method based on Navier-Stokes equations takes the fluids as an uninterrupted entirety and calculates the parameters of movement by means of calculus. To be specific, it includes the finite difference method (hereafter referred to as "the FDM") [31] and the finite element method (hereafter referred to as "the FEM") [32][33][34][35]. Generally, the FDM is based on differential equations.…”

“…Given this deficiency, the FDM is almost replaced by the FEM, which is more flexible in meshing and more applicable to boundaries. Consequently, the FEM is broadly applied in the simulation of fluid flow [32][33][34][35].…”

Upscaling Transmissivity in the Near-Well Region for Numerical Simulation: A Comparison on Uncertainty Propagation

“…Limitation in computer resources forces these models to be upscaled to a modeling (coarse) scale such that a numerical simulator can afford in practical engineering applications of computational fluid mechanics, e.g., petroleum engineering, hydrogeology, environmental engineering, CO 2 sequestration, etc. (see Li et al, 2007;Fu, 2008;Jenny et al, 2003). A large number of upscaling approaches have been developed to coarsen detailed aquifer or reservoir models into those at an appropriate scale for numerical simulations (Wen and GomezHernandez, 1996; Renard and de Marsily, 1997).…”