含水性及水动力条件对煤层瓦斯逸散与赋存的控制作用

Controlling role of hydrous and hydrodynamic conditions on gas fugitive and deposition

在大量测试瓦斯基础参数和分析瓦斯地质资料的基础上,从地层含水性及水动力条件基本特征入手,系统研究了二郎矿区含水层水动力条件对煤层瓦斯逸散模式、赋存规律和煤变质程度的影响,且对类似条件的矿区的情况进行了对比。结果表明:5号和8号煤层,瓦斯以垂直向上逸散模式为主,8号煤层瓦斯逸散量较小;受二叠系下统茅口组(P2m)强富水性的含水层的影响,下部的12号煤层瓦斯以垂直向下逸散为主,瓦斯先通过其直接底板,然后通过地下水动力活动性极强的茅口灰岩含水层逸散;12号煤层的瓦斯含量和瓦斯压力小于其上部的5号和8号煤层,瓦斯梯度和突出危险性也小于其上部的5号和8号煤层;由于12号煤层下部的含水层常年的流动性,致使12号煤层储存温度(古地温)略低于上部的5号和8号煤层,从而使得深部的12号煤层变质程度和瓦斯放散性均略低于浅部的5号和8号煤层。

Based on a large amount of gas measurement parameters and gas-geological analysis data, this paper system- atically investigated the effect of Erlang mine aquifer＇ s hydrodynamic conditions on gas escaping mode, gas deposit law, and coal metamorphism degree. Also, a comparison with the mines in similar conditions was made. The results show that the main gas escaping mode at No. 5 and No. 8 coal seams is vertical upward, and the gas escape at No. 8 coal seam is less. Affected by the Lower Permian Maokou（P2m） rich watery aquifer,the main gas escaping mode at No. 12 coal seam is vertical downward. The gas escapes through the direct seam floor firstly, and then goes through Maokou limestone aquifer which has highly active groundwater dynamics. The No. 12 coal seam gas content and pres- sure are less than that at No. 5 and No. 8 coal seams situated above it. The gas gradient and outburst risk at No. 12 coal seam are less than that at No. 5 and No. 8 coal seams. Due to the flow at the lower part of No. 12 coal seam aquifer,the temperature in No. 12 coal seam（paleo-geotherm） is slightly lower than that in No. 5 and No. 8 coal seams, which makes both the metamorphic grade and the gas diffuse in No. 12 coal seam are slightly lower than that in No. 5 and No. 8 coal seams.