Mathematical Simulation of Hydraulic Fracturing of Shale Strata

Because of continuing demand for energy from fossil fuels, low-permeability hydrocarbon-bearing rocks such as stiff shales and tight sandstones are regularly stimulated using hydraulic fracturing technology ( Curtis 2002 ). In a similar vein, development of intermediate-grade geothermal resources in low-permeability igneous and sedimentary rocks also requires hydraulic fracture stimulation. Most stiff rocks are naturally fractured, which affects hydraulically induced fracture direction locally, but the global orientation of induced fracture growth remains normal to the minimum principal stress. The key factor for economic success is to maximize the stimulated volume and the surface area across which heat, oil or gas can diffuse.