Multiscale Fracture Characteristics of Coal and Their Influence on Fracture Propagation

The complex natural fracture system in coalbed methane reservoirs plays a critical role in hydraulic fracture propagation. This study investigates coal specimens collected from the subsurface of the Ordos Basin (North China). By integrating CT scanning, X-ray diffraction, nanoindentation, and compression tests, the authors systematically characterized the natural fracture development, mineral composition, and mechanical properties of the coal. Based on these data, a numerical model of coal formation was established using the discrete fracture network (DFN) method to evaluate the influence of natural fracture characteristics on hydraulic fracture propagation. Finally, based on a field fracturing case, recommendations for fracturing treatment design are proposed.