A numerical investigation of hydraulic fracturing on coal seam permeability based on PFC-COMSOL coupling method

Abstract Hydraulic fracturing and permeability enhancement are effective methods to improve low-permeability coal seams. However, few studies focused on increase permeability, there no suitable prediction for engineering applications. In this work, PFC2D software was used simulate seam hydraulic fracturing. The results were in a coupled mathematical model of the interaction between deformation gas flow. show that displacement velocity particles direction minimum principal stress, cracks propagate maximum stress. pressure drop rate fracture higher than non-fracture model. Both parameters decrease rapidly with an drainage time approach 0. longer time, more complex network is, faster drops. impact effect declines over time. As increases, difference horizontal vertical increases. decreases as initial void pressure, drops, greater is. influence research provide guidance predicting anti-reflection underground mines.