小窑火区下回采工作面易发生上隅角低氧和有害气体超限，严重制约着矿井安全生产。为理清采空区有害气体的运移规律，以达西定律、扩散定律、流体动力弥散定律为基础构建了采空区气体运移的数学模型，利用COMSOL Multiphysics反演了沙坪矿13102工作面采空区有害气体的运移过程。结果表明：新鲜风流从进风巷道以及工作面流入采空区，然后从上隅角流出，在风流的带动下CH₄和CO从上隅角流出，导致工作面上隅角CH₄和CO体积分数超限、工作面低氧，在此基础上提出上隅角埋管抽采和均压通风的措施防治工作面上隅角低氧、有害气体超限，数值模拟发现上隅角埋管抽采只能防治工作面低氧的问题，而均压通风既能够防治工作面低氧还能阻止采空区有害气体涌向工作面。

Low oxygen and excessive harmful gas in upper corner are easy to occur in the lower mining face under sealed fire area of small coal mine, which seriously restricts the safe production of coal mine. To clarify the migration law of harmful gas in goaf, a mathematical model of gas migration in goaf was derived based on Darcy’s law, diffusion law and hydrodynamic dispersion law. The migration process of harmful gas in goaf in 13102 working face of Shaping Mine was simulated using COMSOL Multiphysics. The results show that the fresh air in the inlet roadway and working face leaks into the goaf, and then flows out from the upper corner of the return air roadway. Driven by the fresh air, CH₄ and CO flows out from the upper corner, resulting in excessive CH₄ and CO and low oxygen at the upper corner of the working face. On this basis, the measures of buried pipe for extraction at upper corner and balanced pressure ventilation are put forward to prevent low oxygen and harmful gas at the corner of the working face. The buried pipe for extraction at upper corner can only prevent the problem of low oxygen in the working face, while the balanced pressure ventilation can prevent the low oxygen in the working face and prevent the harmful gas from flowing to the working face.