With the application of shear displacements of 12.5 mm, 25 mm and 50 mm to large synthetic fractures created on a computer by a new spectral method, the initial aperture (the aperture when the surfaces are in contact at a single point) was determined for a square area with a side length of from 0. l m to 6.4 m. By taking aperture data at constant intervals to establish a flow area, macroscopic water flow both parallel and perpendicular to the shear displacement was simulated for fractures during closure by solving Reynolds equation to determine the hydraulic aperture. When the fracture is closed after shearing, the hydraulic conductivity shows remarkable anisotropy due to the formation of both channels and ridges perpendicular to the shear displacement. This anisotropy becomes more remarkable with both shear displacement and closure. Thus, the hydraulic transmissivity of a sheared fracture between two boreholes is much greater when the two boreholes are aligned perpendicular to the shear displacement than when they are aligned parallel to the shear displacement. Furthermore, water flow is more localized as shear displacement increases, since fewer channels and ridges with a greater area are formed as shear displacement increases. Thus, a sheared fracture is not always hydraulically conductive when the permeability of the fracture is estimated for a small area, as in borehole logging.
- Anisotropic flow
- Heterogeneous flow
- Synthetic fracture
ASJC Scopus subject areas
- Renewable Energy, Sustainability and the Environment
- Energy Engineering and Power Technology