近水平特厚煤层分层开采瓦斯含量立体分布规律分析

Study on the Three-dimensional Distribution of Gas Content in Stratified Mining Extra-thick Flat Seam

针对近水平特厚煤层分层开采工作面煤层厚度大、瓦斯含量高、抽采效果检验无法准确掌握整体抽采效果的问题,以白芨沟煤矿特厚煤层分层开采工作面为工程背景,通过研究特厚高变质无烟煤瓦斯赋存规律,在对现场不同抽采时期、不同层位煤层瓦斯含量进行大量、精准测定的基础上,开展了近水平特厚煤层分层开采瓦斯含量立体分布规律研究。结果表明:走向上,越靠近工作面开切眼,煤层残存瓦斯含量越高;倾向上,越靠近运输巷,煤层残存瓦斯含量越高;垂向上,沿厚度方向特厚煤层中部残存瓦斯含量较高,沿顶、底板方向残存瓦斯含量呈逐渐降低趋势。据此提出基于抽采条件下的特厚煤层残存瓦斯含量立体分布概念,构建了白芨沟煤矿特厚煤层区域立体抽采条件下不同层位煤层的残存瓦斯含量与抽采时间的关系模型,补充完善了矿井瓦斯地质管理体系,为指导抽采钻孔布置和确定抽采效果检验目标层提供了科学依据。

In view of the problems of large thickness of coal seam,high gas content and inability to accurately master the overall extraction effect in layered mining working face of extra-thick flat seam,taking the stratified mining working face of extra-thick seam in Baijigou Coal Mine as the engineering background,by studying the gas occurrence law of extra-thick and high metamorphic anthracite coal,on the basis of the large amount and accurate determination of gas content of coal seam in different extraction periods and different strata on site,the study on the three-dimensional distribution of gas content in stratified mining of extra-thick flat seam was carried out.The results show that,on the strike,the more close to the working face cutting,the higher the residual gas content of coal seam;in the trend,the closer to the transport lane,the higher the residual gas content of coal seam;in the vertical direction,the residual gas content in the middle of the extra-thick coal seam is relatively high and the residual gas content decreases gradually along the direction of roof and floor.On this basis,the concept of three-dimensional distribution of residual gas content in extra-thick coal seam was put forward.The relationship model between residual gas content and extraction time of coal seam in different positions under the condition of three-dimensional extraction in extra-thick coal seam of Baijigou Coal Mine was established.Therefore,the system of mine gas geology management was supplemented and perfected,which provided scientific basis for guiding the layout of extraction borehole and determining the inspection target layer of extraction effect.