Implementation and Verification of the Fully Coupled T-H-M Code, T2STR, for Multiphase Flow in Porous Media

Abstract

We present the formulation details of the research code T2STR, capable of simulating a fully coupled thermo-hydro-mechanical (THM) analysis of porous media under multiphase conditions. The IFDM based computer code TOUGH2 is modified using features from FEM based computer code Geocrack3D to include the mechanical effects. The dual mesh technique is natural for combining both discretization methods and is used in our implementation.

T2STR is implemented to carry out a fully coupled, one way coupled (only deformation as function of hydro-thermal effects), and original TOUGH2 simulations. T2STR also allows the user to study the variation in porosity, permeability and capillary pressure as function of mean effective stress in both the one-way and fully coupled approaches. The coupled sets of equations in T2STR have been combined using the dual mesh concept.

Numerical examples are presented to show the accuracy and capability of the enhanced T2STR code.

The code modifications to TOUGH2 and the additional code required to run the fully coupled simulations will be publicly available and will be posted on the web.