Recent advances in hydraulic fracturing (HF) have allowed for commercially viable extraction of oil/gas from deep underground shale formations previously deemed uneconomical to exploit. Indeed, HF promises to be one of the key industries for future energy exploitation. However, the use of HF in unconventional oil/gas extraction has generated controversy, so that several countries have imposed moratorium on its use for unconventional hydrocarbon extraction. Opponents of HF claim that its use poses severe environmental risks such as contamination of groundwater resources, that it depletes freshwater supply and induces seismicity.To gain a better understanding of the HF-process, the applicant proposes to develop, implement, verify and validate a 3D stochastic computational multiscale & multiphysics framework. The measurable outcome of this research will be an open-source software package that can be used to study and better understand HF and finally to improve current-practice HF.Within the computational framework, fluid flow through the evolving 3D fracture network will be modelled on a 2-stage reservoir scale. Fine-scale simulations will be performed in order to more reliably predict macroscopic material parameters at the 2-stage reservoir scale. Moreover, based on (stochastic) uncertain input parameters, the applicant will quantify uncertainties in order to provide upper and lower bounds of her predictions. The researcher will provide a framework based on graph-theory and sensitivity analysis to choose the appropriate model and discretization. This computational framework will be verified and validated by comparison to experiment and site data, and will be used to answer some of the most pressing issues in HF, e.g. the interaction between fracture networks at different stages, the possibility of the fracture network encroaching into adjacent layers of rock or the interaction of fractures with existing natural faults that intersect the shale seam, to name a few.