Coupled thermo-hydro-mechanical (THM) process is an important and hot-spot issue. Based on Biot consolidation theory and Morh-Coulomb failure criteria

coupled THM model is built in the framework of TOUGH2 which is a multiphase fluid flow

nonisothermal simulation software. At the same time

a new simulator-TOUGH2Biot is developed with fully coupling between thermal and hydrodynamic processes and partly coupling for mechanics

using mixed integral finite difference and finite element method. Analytical solution is employed to verify the simulator. Finally

TOUGH2Biot is used to numerically analyze the THM response of formations after CO2 injection. The results show that the CO2 injection induces to a quick increase in fluid pressure and corresponding decrease in effective stress. Consequently

there is an uplift of tens of centimeters at the surface. Also

the porosity and permeability are enhanced

which are favorable for dissipation of pressure buildup. The most possibility of shear slip failure is at the caprock above the maximum injection rate location. The second potential failure location is near the surface.