In this study, a coupled poro-elasto-plastic Finite Element Method (FEM) is used to calculate a set of scenarios of fault reactivation which could occur. The potential for fault reactivation is estimated numerically for faults surrounding a well designed for drilling cuttings reinjection in offshore West Africa. This well is in a block bordered with 3 major faults. The results of these calculations on fault reactivation are used to design the injection pressure and further control the total volume of drilling cuttings which can be safely injected. Numerical results obtained with the FEM model include: distribution of equivalent plastic strain within the whole model, distribution of von Mises equivalent stresses, and the displacement field under a given pore pressure boundary condition at the bottom of the model. The plastic region is the area where the fault is being reactivated. In this way, results of both the location and the level of fault reactivation are obtained and visualized. The numerical results are shown for the plastic strain distribution at the stage where the plastic region is growing up to the top of the fault zone and the distribution of the von Mises stresses.
In this study, both experimental and numerical studies were performed to investigate the impact of a bi-material interface on crack propagation. A set of thickness values for the weak interfacial layer was used in the experiments to investigate its influence on fracture propagation. In the numerical studies, the aforementioned experimental phenomena were simulated first, with the focus on calibrating the numerical model. Second, a numerical investigation of the influence of the strength and stiffness of the interface layer on crack propagation was performed. The influence of the interface layer permeability on the propagation of hydraulically generated fractures across the interface layer was also investigated. During the numerical studies, a simplified 3D Finite Element Model was built and used. The poroelastic plastic damage model is used to simulate crack propagation. The load of the numerical model for the 1st set of calculations is the point force in 3-point bending, which simulates the experimental phenomena. Loads in the 2nd set of calculations include the gravity load which balances the initial geostress field and the fluid injection flow rate. The results obtained can be used as a reference in the design of hydraulic fracturing for laminated thin formations.