Non-isothermal two-phase flow in low-permeable porous media

Abstract

In this paper, we consider non-isothermal twophase flow of two components (air and water) in gaseous and liquid phases in extremely low-permeable porous media through the use of the finite element method (FEM). Interphase mass transfer of the components between any of the phases is evaluated by assuming local thermodynamic equilibrium between the phases. Heat transfer occurs by conduction and multiphase advection. General equations of state for phase changes (Clausius-Clapeyron and Henry law) as well as multiphase properties for the low-permeable bentonites are implemented in the code. Additionally we consider the impact of swelling/shrinking processes on porosity and permeability changes. The numerical model is implemented in the context of the simulator RockFlow/RockMech (RF/RM), which is based on object-oriented programming techniques. The finite element formulations are written in terms of dimensionless quantities. This has proved to be advantageous for preconditioning composite system matrices of coupled multi-field problems. Three application examples are presented. The first one examines differences between the Richards' approximation and the multicomponent/multiphase approach, and between two numerical coupling schemes. The second example serves as partial verification against experimental results and to demonstrate coherence between different element types. The last example shows simultaneous desaturation and resaturation in one system.

Numerical Simulation of Multiphase Hydromechanical Processes Induced by CO2Injection into Deep Saline Aquifers

“…Numerical strategies for the treatment of thermo-hydromechanical processes are introduced in e.g. [49][50][51][52].…”

Non-isothermal flow in low permeable porous media: a comparison of Richards’ and two-phase flow approaches

“…The fluid mass balance equations under non-isothermal conditions can be derived from the mass conservation law (Kolditz and De Jonge 2004;Lewis and Schrefler 1998;Rutqvist et al 2001;Sanavia et al 2006). The component form (i.e.…”

“…The heat transport equation for two-phase flow in porous media can be derived from the energy balance (Gray and Hassanizadeh 1991;Kolditz and De Jonge 2004). The coupling with fluid flow is represented by two convective transport terms (for liquid and gas) in the governing equation as follows…”

Modeling Thermal-Hydrologic Processes for a Heated Fractured Rock System: Impact of a Capillary-Pressure Maximum

“…The simplest extension methods of the van Genuchten capillary-pressure curve is a flat (FCPC) curve, which assigns a constant CPC in the dry region (Finsterle 2002;Kolditz and De Jonge 2004) and follows the van Genuchten curve in the wet region (curve ABE of Fig. 1a) …”