Abstract:

THM coupling analysis in porous medium has an important research significance in geological sciences such as nuclear waste geological storage, hot dry rock, CO₂ geological storage, etc.，in which numerical method is often required in view of its computational complexity. TOUGHREACT is joined together with FLAC^3D using grid conversion between the corner points and center point as well as three dimension three point Lagrange interpolation methods, and realizes the multiphase and multicomponent fluid-temperature-rock mechanics coupling analysis. In order to verify the efficiency and applicability of the program, numerical model of CO₂ sequestration into underground saline reservoir in Salah is founded, and three years continuous injection of CO₂ is simulated. Fluid migration and reservoir, cap rock mechanics variation underground is evaluated, and the ground surface displacement is compared with measured values by inSAR. Then a further simulation of three-dimensional cylinder injection model of CO₂ sequestration in a basin of West China is done. The applicability of the coupled program TOUGHREACT-FLAC^3D is demonstrated. The results under the influence of mechanics on the injection pressure as well as the displacement of ground surface are reasonable and in a good agreement with the monitoring value, and some other mechanical results are also obtained.

Key words: THM coupling in porous medium, code research, TOUGHREACT-FLAC^3D, numerical analysis, storage