Numerical Study on the Field-Scale Criterion of Hydraulic Fracture Crossing the Interface Between Roof and Broken Low-Permeability Coal

In areas of broken soft and low-permeability coal, indirect hydraulic fracturing (HF) coal is a technology with great potential to increase coal bed methane (CBM) production. The key to success of the technology is that HFs can cross the coal–rock interface from the roof and propagate into the coal. To this end, this article focuses on the roots that hinder the HFs propagating enough in the coal, that is, the significant inelastic deformation...