复杂瓦斯地质条件下煤层透气性评价及抽采对策研究

Study on coal seam gas permeability evaluation and drainage countermeasures in complex gas geological conditions

针对煤层瓦斯地质条件复杂的米箩煤矿在生产过程中瓦斯抽采难、预抽时间长、矿区范围内可采煤层透气性不确定的问题,采用煤层透气性系数现场测定的方法,对米箩煤矿1号、3号、9号、10号、16号、26号、27号、29号、31号和40号煤层施工测压钻孔进行了煤层透气性系数相关参数的测定,并依据钻孔径向流量法计算公式,对米箩煤矿各煤层透气性系数进行了评价,得出了米箩煤矿矿区范围内1号、3号、9号、10号、16号、26号、27号、29号、31号和40号煤层均为低透气性煤层。通过优化瓦斯抽采钻孔直径和钻孔间距的方式,改善了煤层透气性,并在1108底板瓦斯抽放巷两侧每隔15 m分别增设一个高位钻场,在钻场内向3号煤层布置19个斜向穿层抽采钻孔,有效缩短了110310回采工作面瓦斯预抽时间。

The geological conditions of Miluo Coal Mine is complex, in the production process, gas is difficult to drain, the time of gas drainage is long, and permeability of minable seam was uncertain, aimed at these problems, the permeability coefficient measuring on site was applied, thus, pressure drilling were constructed in No. 1,3,9,10,16,26,27,29,31 and No. 40 coal seam, whose purpose was to evaluate the permeability coefficient of coal seams. It was proposed that No. 1,3,9,10,16,26,27,29,31 and No. 40 are of low per- meability coal seam. Through the optimization of diameter and spacing of holes for gas drainage, the permeability of coal seam was im- proved, high-level drilling field was added on two side of 1108 floor drainage roadway, and the spacing of drilling field was 15 m. 19 ob- lique layer-through boreholes were laid out into No. 3 coal seam in the drilling field, and this has effectively reduced the pre-pumping time of the gas on 110310 working face.