The stability of shale gas wells drilled through current and future coal reserves can be compromised by ground deformations due to nearby longwall mining. Depending on the longwall-induced rockmass permeability, the high-pressure explosive gas from the damaged well may reach mine workings and overwhelm the mine ventilation systems. This study uses geomechanical models to estimate the rockmass permeability induced by mining. A two-panel longwall model of a deep, 341-m-cover mining site in southwestern Pennsylvania is constructed in 3DEC to explicitly model the rockmass by a discrete fracture network (DFN) technique. Stress-induced fracture apertures and permeabilities are calculated across the model and are validated against permeability measurements. A fracture flow code (FFC) is developed to use these results to predict potential inflow to the mine should a gas well breach occur. One hundred DFN realizations are simulated, and the results show that for a gas pressure of 2.4 MPa, the average of the predicted inflow rates to this deep-cover mine is 0.006 m³/s, significantly lower than the average inflow of 0.22 m³/s for a shallow-cover mine (145-m deep) studied in the previous work (Khademian, et al. 2021). The result can help assess the potential hazards of a shale gas well breach for mine safety and evaluate the ventilation requirements to mitigate the risk.

通过当前和未来煤炭储量钻探的页岩气井的稳定性可能会因附近的长壁开采而受到地面变形的影响。根据长壁引起的岩体渗透率，来自受损井的高压爆炸性气体可能会到达矿井并淹没矿井通风系统。本研究使用地质力学模型来估计采矿引起的岩体渗透率。在 3DEC 中构建了宾夕法尼亚州西南部一个 341 米覆盖的深矿场的两面板长壁模型，以通过离散裂缝网络 (DFN) 技术明确模拟岩体。在整个模型中计算应力引起的裂缝孔径和渗透率，并根据渗透率测量结果进行验证。开发了压裂流代码 (FFC) 以使用这些结果来预测在发生气井破裂时可能流入矿井的流量。模拟了一百个 DFN 实现，结果表明，对于 2.4 MPa 的气体压力，该深盖矿的预测流入流量的平均值为 0.006 m³ / s，显着低于先前工作中研究的浅层矿山（145 米深）的平均流入量 0.22 m ^{3 / s（Khademian 等，2021）。}该结果有助于评估页岩气井破裂对矿山安全的潜在危害，并评估通风要求以降低风险。