The key mechanical problems on hydraulic fracture in shale

The exploitation of shale gas has become a promising field of green energy development in China. Although great success has been achieved in shale gas revolution in North America with the technique of hydraulic fracturing, only 5%-15% of the stored oil and gas could be exploited. Where was the problem occurred? A huge challenge accompanied with great opportunity is presented to the mechanics researchers. This paper explores the mechanical mechanism and control of complex fracture network in hydraulic fracturing in theory, numerical simulation and experiments. It includes the experimental platform for large objects model, time-dependent anisotropic Biot constitutive, the fracture criteria and simulation methods for fracture initiation, branching and interaction of multiple cracks and multi-scale models for steadily extending fracture families, as well as numerical software for modeling hydraulic fracture network, in which both fracture mechanics and fluid mechanics can be considered.