oa Fault Reactivation and Fault Properties – 3D Geomechanical Modeling Approach and Application to Nuclear Waste Disposal

We present the preliminary results of a methodology that consists on modeling 3D fault reactivation and to relate both the computed fault slip and residual stresses to fault seal and leakage capacity. A series of geomechanical simulations is run on a 3D fault model, which integrates friction, cohesion, far field stress and fluid pressure as variables. The hundreds of simulations are analyzed as a whole in order to determine the likelihood of fault reactivation with respect to the variable parameters. Each reactivated fault is then analyzed independently. Fault sealing and/or leakage capacity can be estimated when the relationship between computed fault slip and/or residual stresses and fault zone deformation mechanisms is known. The methodology has been applied and tested on the Olkiluoto nuclear waste repository site, Finland. The method can be applied to petroleum reservoirs, where depletion can affects fault reactivation, hence fault sealing and leakage reliability.