Hydromechanical Behavior of a Fracture: How to Understand the Flow Paths
A combination of experimental and modeling techniques have been developed to identify and monitor the evolution of flow paths in natural fractures under normal and shear stresses. A casting method allows the morphology of the fracture to be analyzed in conjunction with the results of traditional hydromechanical tests. Modeling indicates that deformation of the fracture surfaces that occurs with increasing stress results in changes in void space geometry that could have a substantial affect on the hydromechanical response of the fracture. For fractures under a shear stress, the spatial distribution of flow is shown to be related to the damage zones that evolve with increasing tangential displacement. Results of laboratory experiments, during which fluid recovery is monitored, show that flow is progressively re-oriented during shearing in a direction subperpendicular to the shear direction.