Opalinus Clay formation (OPA) is an indurated shale under study in the context of geological deep disposal of nuclear waste in Switzerland. We will study the frictional properties of fault zones in OPA to evaluate the long-term safety performance of the repository. A better understanding of fault stability and possible related leakages are the main goals. In this project, we will focus on the effect of pore fluid pressure and micro-structural texture on the frictional properties of OPA. Series of friction experiments at different slip velocities and normal stress, on solid and granular material will be carry out. We have considered dry, fluid-saturated, and fluid reactive environments for the planned tests. The main objective is to study the mechanisms involved during deformation and fracture permeability change. Using a bi-axial and a rotary shear apparatus, the systematic study of experimental faults should allow us to identify the couplings between hydraulic and mechanical properties, but also alteration reactions occurring during deformation. Systematic investigations with different techniques have being carried out, and are planned to characterize OPA faulting zone. Among the techniques, we have studied the microstructure through X-Ray powder diffraction, Atomic Force Microscopy (AFM), SEM images and others. Petro-physical properties have been measured such as porosity (Mercury Intrusion Porosimetry and permeability (transient state method). First results on the characterization of the faulting zone properties are presented.