The environmental risks associated with casing deformation in unconventional (shale) gas wells positioned in abutment pillars of longwall mines is a concern to many in the mining and gas well industry. With the recent interest in shale exploration and the proximity to longwall mining in Southwestern Pennsylvania, the risk to mine workers could be catastrophic as fractures in surrounding strata create pathways for transport of leaked gases. Hence, this research by the National Institute for Occupational Safety and Health (NIOSH) presents an analytical model of the gas transport through fractures in a low permeable stratum. The derived equations are used to conduct parametric studies of specific transport conditions to understand the influence of stratum geology, fracture lengths, and the leaked gas properties on subsurface transport. The results indicated that the prediction that the subsurface gas flux decreases with an increase in fracture length is specifically for a non-gassy stratum. The sub-transport trend could be significantly impacted by the stratum gas generation rate within specific fracture lengths, which emphasized the importance of the stratum geology. These findings provide new insights for improved understanding of subsurface gas transport to ensure mine safety.

与位于长壁矿井台柱中的非常规（页岩）气井套管变形相关的环境风险是采矿和气井行业的许多人关注的问题。由于最近对页岩勘探的兴趣以及宾夕法尼亚州西南部靠近长壁开采区，矿工面临的风险可能是灾难性的，因为周围地层的裂缝为泄漏气体的输送创造了通道。因此，美国国家职业安全与健康研究所 (NIOSH) 的这项研究提出了一种气体通过低渗透地层中的裂缝输送的分析模型。导出的方程用于对特定输运条件进行参数研究，以了解地层地质、裂缝长度和泄漏气体性质对地下输运的影响。结果表明，地下气体通量随着裂缝长度的增加而减少的预测是专门针对非含气地层的。特定裂缝长度内的地层产气率可能显着影响次输运趋势，这强调了地层地质的重要性。这些发现为更好地了解地下气体输送以确保矿山安全提供了新的见解。