The injection of CO2 will give rise to a variety of coupled physical and chemical processes, which may affect the hydraulic integrity of caprocks. Likewise, when CO2 is stored as a component of EOR projects, the initial depletion of the reservoir, and all the influences associated with the EOR processes may affect the hydraulic integrity of caprocks. Therefore, it is necessary to understand how the hydraulic integrity evolves to make geological storage of greenhouse gases a feasible option. Such information must be imbedded in a performance assessment to determine the integrity of a reservoir and its caprock over an extended period of time. A preliminary methodology to evaluate the hydraulic integrity of the Weyburn project is presented.