Jeanne, Pierre (Lawrence Berkeley National Laboratory) | Rinaldi, Antonio Pio (Lawrence Berkeley National Laboratory) | Rutqvist, Jonny (Lawrence Berkeley National Laboratory) | Cappa, Frédéric (Lawrence Berkeley National Laboratory) | Guglielmi, Yves (CEREGE (UMR7330))
Abstract: In this study, we have examined the influence of the fault zone characteristics on pressure diffusion and fault reactivation by CO2 injection. Especially, we studied the effect of lithological and rock physical properties on the fault zone response inside a multilayer sedimentary system. Through numerical analysis, we compared four models where the complexity of the fault zone internal architecture is considered. Results show how the presence of hydromechanical heterogeneity influences the pressure diffusion, as well as the effective normal and shear stress evolutions. The more complex the fault zone architecture is and the more heterogeneities that are present, the faster the pressurization within the damage zone occurs. But, these hydromechanical heterogeneities (i) strengthen the fault zone resulting in earthquake of smaller magnitude, and (ii) impede fluid migration along the fault. We also show that the effects of the hydromechanical heterogeneities within the reservoir are negligible relative to those between the caprock and the reservoir.