潘三煤矿11-2煤穿层钻孔的优化布置

穿层钻孔的布置方式是影响瓦斯抽采效果的重要因素之一。为研究潘三煤矿11-2煤穿层钻孔布置方式对瓦斯抽采的影响,笔者以该矿2121(1)运顺瓦斯综合治理巷为工程研究对象,分析10×5,8×6和7×7穿层钻孔布置方式对瓦斯抽采的影响。基于对煤层瓦斯的一系列假设建立了煤层瓦斯气固耦合模型,利用有限容积和牛顿迭代法对3种钻孔布置方式的瓦斯抽采过程进行数值模拟,并对这3种钻孔布置方式的钻孔施工工程量和单孔平均抽采瓦斯纯量进行了现场试验考察。结果表明:采用7×7与8×6布孔方式在相同抽采时间下留有空白带面积明显小于10×5,而且它们在消除空白带所需的时间上也少于10×5,由此看出10×5布孔方式最不利于消突;8×6钻孔布置所需钻孔施工工程量最少,而7×7钻孔工程量最多;7×7布孔方式的单孔平均抽采瓦斯纯量略高于8×6,而10×5布孔方式单孔平均抽采瓦斯纯量最低。结合数值模拟和现场试验结果得出,采用8×6钻孔布置方式最优。该研究结果对煤矿井下穿层钻孔设计具有一定的指导作用。

Effects of cross-seam borehole layout on gas extraction in the Pansan mine

The layout of cross-layer boreholes is one of the important factors affecting the efficiency of gas extraction. In order to study the effects of the layouts of cross-seam boreholes on gas extraction, gas control roadway 2121(1) in the Pansan mine was taken as the research object in this paper to analyze the effects of the three kinds of layouts of cross-seam boreholes, 10×5, 8×6 and 7×7, on gas extraction. The gas-solid coupling model of coal seam based on fracture-pore dual media was established, and the gas extraction processes of the three kinds of borehole layouts were simulated numerically by using finite volume method and Newton iteration method. And the engineer quantity of boreholes and the average pure gas flow volume extracted in the 30 days were investigated at the field. The results show that the "blank zone" area of the borehole layout 8×6 and that of 7×7 are smaller obviously than that of 10×5 under the same time of gas extraction. And the extraction time required for the elimination of "blank zone" is less than that of the borehole layout of 10×5. So, the borehole layout of 10×5 is bad for eliminating gas outburst. The engineer quantity of the borehole layout of 8×6 is the smallest and that of the borehole layout of 7×7 is the largest. The average pure flow volume daily by single borehole of the borehole layout of 7×7 is larger slightly than that of the borehole layout of 8×6, and that of the borehole layout of 10×5 is the smallest. The results of the numerical simulation and the field experiments considered, it is obtained that the borehole layout of 8×6 is the optimal. The result of this study provides a good guidance for the design of cross-seam boreholes in a coal mine.