煤层群开采工作面瓦斯涌出来源及比例的定量分析，是矿井瓦斯抽采设计与治理的重要前提。稳定碳氢同位素法基于瓦斯气体混合前后碳、氢同位素总量各自保持不变的原理，可以对工作面瓦斯各来源比例进行定量计算，成为工作面瓦斯精准定量溯源的有效方法。稳定碳氢同位素分析实现的必要条件是混合气样的瓦斯体积分数不低于10%，对此，首先提出煤层群开采工作面瓦斯精准定量溯源原理，并构建了高效分离低浓度瓦斯方法，研究了吸附柱中甲烷、氧气和氮气的分离规律，对比确定了优化的吸附剂种类和吸附柱尺寸，对上隅角、回风巷等地点的超低浓度瓦斯进行分离，进而进行稳定碳氢同位素测试。然后通过测得的各煤层端元气体以及工作面不同位置混合气体的甲烷碳、氢同位素值，利用二端元、三端元线性混合模型，定量分析了西山矿区东曲矿和屯兰矿的4个试验工作面各位置瓦斯来源的占比及规律。最终确定了近距离煤层群回采工作面瓦斯的重点抽采目标：工作面上隅角只有5%来自上邻近层，本煤层占比达到78%，因此应着力加大本煤层瓦斯抽采强度；采空区、上隅角、回风巷的瓦斯主要来源于本煤层卸压瓦斯，从采空区到上隅角和回风巷，上邻近层瓦斯占比呈现上升趋势；采空区、上隅角瓦斯各来源比例受工作面推进度影响较小，基本维持稳定。煤层群开采工作面瓦斯精准定量溯源技术实施简便，效果显著，有效解决了上隅角、回风巷等地点精准定量溯源的重大工程难题。

Quantitative analysis of the source and proportion of gas emission from longwall face of coal seams is an important prerequisite for mine gas drainage design and management. The stable hydrocarbon isotope method is based on the principle that the total amount of carbon and hydrogen isotopes remain unchanged before and after the gas is mixed. It can quantitatively calculate the proportion of each source of gas in the working face and become an effective method for accurate and quantitative traceability of the gas at the working face. The necessary condition for the realization of stable hydrocarbon isotope analysis is that the concentration of gas mixture is not less than 10%. In this regard, the principle of accurate and quantitative gas traceability at the coal mining face was firstly proposed,and a method for efficiently separating low-concentration gas was constructed.The separation law of methane, oxygen and nitrogen in the adsorption column was compared and the optimized adsorbent and the size of the adsorption column were compared and determined. The ultra-low concentration gas in the upper corner, return airway and other places was separated and further measured for carbon and hydrogen isotopes.hen, based on the measued carbon and hydrogen isotope values of methane in the end-member gas of each coal seam and the mixed gas at different positions of the longwall face,the proportion and regularity of gas sources in each position of the four tested longwall faces (Dongqu mine and Tunlan mine in Xishan mining area) were quantitatively analyzed using the linear mixing model of two and three end members. Finally, the key gas drainage targets for the working face of the short-distance coal seams were determined: Only 5% of the gas in the upper corners come from the upper adjacent seam, and the current coal seam accounts for 78%, indicating that efforts should be made to increase the gas drainage intensity of the current coal seam. The gas in the gob, upper corner and return airway mainly comes from the pressure relief gas in the current coal seam, and the proportion of gas from the upper adjacent layer shows an upward trend from the goaf to the upper corner and return airway. The ratio of each source in the gob and upper corner gas is less affected by the advancement of the working face and remains basically stable. The technology of precise and quantitative traceability of gas in coal seam mining face is easy to implement and has significant effects. It effectively solves the major engineering problems of precise and quantitative traceability in places such as upper corners and return airways.

0 引言

1 工程概况

   1.1 东曲矿试验工作面

   1.2 屯兰矿试验工作面

2 低浓度瓦斯溯源技术原理

   2.1 N端元线性混合模型

   2.2 低浓度瓦斯分离与精准溯源

3 工作面瓦斯涌出来源比例定量分析

   3.1 混合瓦斯来源判别计算

   3.2 不同工作面瓦斯涌出来源比例分析

   3.3 瓦斯涌出来源比例随工作面推进的规律

4 结论