Geological CO2 storage under subsurface formation is a promising strategy to reduce the amount of greenhouse gas in the atmosphere. However, CO2 injections can alter the formation pressure distribution, potentially leading to geological fault reactivation and caprock integrity failure. Moreover, the interaction between CO2 storage mechanisms and pressure buildup plays a critical role in the geomechanical stability of geological faults [1]. This work investigates the influence of different CO2 storage mechanisms on pressure buildup and its implications for fault reactivation assessment. The Mohr-Coulomb failure criterion is adopted to evaluate fault stability. The proposed approach integrates compositional multiphase and geomechanical simulators using sequential coupling strategies [2]. The numerical results show that structural trapping often results in higher pore pressure diffusion that can easily reach sealed geological faults, compromising the fault stability. In contrast, residual and solubility trapping contribute to more uniform pore pressure distribution by immobilizing CO2 within the pore spaces and dissolving CO2 into the formation fluid, respectively. Although the studied scenarios are synthetic, the results provide valuable insight into the interaction between CO2 storage mechanisms and geomechanical responses, highlighting the need for optimized injection strategies to mitigate fault reactivation risks.