Geomechanical stability analysis of reservoir rock related to CO2 injection in Japan

In the CO2 geo-sequestration, CO2 gas is injected into deep aquifer by high injection pressure. As the results, the pore pressure will be increase from the initial state. This is corresponding to decreasing "effective stress", which is acting on the reservoir and cap rock system. The change in effective stress causes the geomechanical response of deep strata, e.g. deformation of rock, induced seismicity. We evaluated the geomechanical stability of reservoir and caprock at Tomakomai candidate site in order to evaluate the effect of planned CO2 injection on geomechanical stability of the reservoir based on "slip tendency". The slip tendency around injection point where maximum pore pressure built-up was estimated about 0.495, which means geomechanical instability will unlikely occur by planned CO2 injection.