Porosity and conductivity (or permeability) are the two main hydraulic properties of rocks in subsurface reservoirs (freshwater aquifers, geothermal systems, hydrocarbon reservoirs). Porosity measures the ability of the rock to store fluids in pore spaces and in fractures. The hydraulic conductivity KH describes the ease with which a fluid can move through open rock conduits. The main geomechanical parameters of rocks are: absolute permeability k , Young’s modulus of elasticity E, rock bulk compressibility CB, Poisson’s ratio ν, Lamé coefficient λ, shear or rigidity modulus G, bulk modulus KB and thermal expansivity γB. All the petrophysical properties are measured in the laboratory specifically for each system.