Fractured geologic materials have a dramatic impact on subsurface fluid transport because they carry fluid and solutes much more rapidly than the surrounding matrix. During oil and gas production, intentional hydraulic fracturing is common to create highly conductive pathways between the reservoir and the wellbore.

Modeling flow in a fractured reservoir is challenging because of the dramatically different length scales (fracture width to length), the complex fracture geometry, uncertainty about proppant placement, and the complex rheology of fracture fluids. The images shown above depict a computer-generated model of a small section in a propped fracture. The geometry of the fracture surfaces are generated using statistics measured from real fractured rocks; these statistics can be varied to created a wide range of geometries. The simulated proppant is placed into the fracture using the simulated annealing algorithm described in the packed beds section. The image on the far right is a network model of the propped fracture. These computer-generated structures are being used in pore-to-reservoir upscaling studies.