Hydrofracturing is a key process in many areas of pure and applied geosciences, such as the intentional hydraulic fracturing of impermeable rock formations in the hydrocarbon and geothermal energy industries, as well as natural processes in volcanology. However, previous work investigating pressure confined hydraulic fracturing (simulating burial depth) was limited to either (a), in-situ ‘pumping tests’ that monitor only the fluid injection rate and resulting microseismicity with little control on the rock stress, type and anisotropy or (b), laboratory simulations that use homogeneous rocks lined with a rubber membrane that does not permit direct contact between the fluid and rock matrix and is more accurately described as ‘pressure driven tensile fracture’.
In this project, these shortfalls are tackled by conducting a comprehensive set of experiments on anisotropic shales in a rock physics laboratory environment with different pore fluids and stresses. Objectives include: 1, explore the dependence and fracture mechanics behaviour of the fluid driven mechanical fracture process in order to assess the competition between permeability and overpressure upon the derived fracture pattern. 2, test the importance of inherent and induced anisotropy on the fracture pattern. These goals are achieved using the latest generation of triaxial and hydrostatic cells, and with state-of-the-art micro-seismic instrumentation.