Study on the effect of solid particle proppant on fracture support and flow conductivity in coal seam

Coal seam permeability enhancement is a key step in improving gas extraction efficiency and ensuring the safe mining of coal. The proppant plays a decisive role in maintaining the stability and conductivity of the fractures after permeability enhancement. To investigate the influence of proppants on the support characteristics and flow conductivity of coal seam fractures, this study takes the Shanxi Shiquan Coal Mine as the research object. Using the Meyer numerical simulation software, the effects of proppant type (quartz sand, ceramsite), particle size (10–20 mesh, 20–40 mesh, 40–70 mesh), and breakage rate (0%, 25%, 50%, 75%, and 100%) on the evolution of fracture support and conductivity were explored. The results show that, under the support of both quartz sand and ceramsite, the fracture width is reduced by 89.6% and 91.5%, respectively, compared to the initial enhanced permeability fracture. However, both types effectively maintain the fracture conductivity, with the average conductivity of ceramsite being approximately 1.72 times that of quartz sand. Under the same proppant type, the particle size is positively correlated with the fracture support width and conductivity. Specifically, the length-averaged fracture conductivity of 10–20 mesh ceramsite is 2.82 times and 10.95 times higher than that of the 20–40 mesh and 40–70 mesh ceramsites, respectively. Furthermore, the average fracture conductivity under proppant support shows a significant linear correlation with the breakage rate of the proppant. This study clarifies the mechanisms of different proppant types on coal seam fracture enhancement, providing reliable theoretical support and technical reference for proppant selection, particle size optimization, and breakage risk management in permeability enhancement projects for the Shanxi Shiquan Coal Mine and other mines with in-situ stress of approximately 10–30 MPa and coal seam permeability ranging from 1 × 10⁻¹⁸ to 1 × 10⁻¹⁵ m². It also has significant practical engineering implications for improving gas extraction efficiency and ensuring coal mining safety.