Application of rock failure simulation in design optimization of the hydraulic fracturing

Energy production from unconventional geothermal and petroleum resources relies on reservoir stimulation by hydraulic fracturing. Unconventional reservoir stimulation involves multiple fractures possibly propagating in both tensile and shear mode or propagation. Therefore, application of rock fracture mechanics and advanced modeling are necessary for improved understanding of the process and its optimization. This paper presents an overview of hydraulic fracturing conceptual models and rock failure mechanisms followed by a series of numerical simulations and analyses to provide some insight into various phenomena observed in hydraulic fracturing of unconventional reservoirs. In particular, two-dimensional and three-dimensional examples are used to illustrate the impact of hydraulic fracture interactions with each other and with discontinuities and highlight the role of rock anisotropy and heterogeneity and mixed-mode stimulation in relation to permeability change.