Determination of aperture structure and fluid flow in a rock fracture by high-resolution numerical modeling on the basis of a flow-through experiment under confining pressure

A numerical model incorporating experimentally determined fracture surface geometries and fracture permeability is proposed for characterizing aperture structures and fluid flow through rock fractures under confining pressures. The model was applied to artificially created granite tensile fractures with varying shear displacements (0-10 mm) and confining pressures (10-100 MPa). The findings of the study were consistent with those obtained previously, which characterized experimentally determined contact areas and changes in shear stress during the shear process. While the confining pressures considered herein are higher than those of previous studies, experimentally obtained fracture permeability is important for understanding subsurface flow, specifically the fluid flow characteristics in aperture structures under different confining pressures. Development of preferential flow paths is observed in all aperture structures, suggesting that the concept of channeling flow is applicable even under high confining pressures, as well as the existence of 3-D preferential flow paths within the subsurface fracture network. Copyright 2008 by the American Geophysical Union.