高位钻孔优势抽采区分布规律研究

Research on distribution law of dominant gas extraction area of high-level borehole

  • 摘要: 为了提高煤矿高位钻孔抽采瓦斯效率,基于覆岩采动破坏理论和瓦斯运移特征,提出了高位钻孔优势抽采区的概念,即位于冒落带和裂隙带之间的能够保证稳定高效抽采效果的区域。以下沟煤矿作为研究对象,采用数值模拟及现场验证的方法确定了该矿ZF302采煤工作面的高位钻孔优势抽采区,并对其分布规律进行了研究。研究结果表明,ZF302采煤工作面抽采优势区位于顶板垂高为34~57 m的区域;抽采优势区中,单孔瓦斯抽采量呈现出先升高、后平稳、再降低的趋势; 当终孔高度位于70~57 m区域时,单孔瓦斯抽采量从0.66 m3/min逐渐上升至1.48 m3/min,之后在高度57~34 m区域内进入平稳区,单孔瓦斯抽采量始终保持在1.0 m3/min以上;高位钻孔终孔位置位于顶板垂高55~65 m范围内时,优势抽采区的抽采时间最长,单孔瓦斯抽采量最高;钻孔参数优化后,钻场钻孔数量从28个减少到18个,减少了35.71%;日抽采量从26 008.75 m3提升到31 046.4 m3,提升了19.37%。

     

    Abstract: In order to improve efficiency of gas extraction of high-level boreholes in coal mines, the concept of dominant gas extraction area of high-level boreholes was put forward based on theory of overburden strata mining failure and characteristics of gas migration, that is, the area between caving zone and fracture zone that can guarantee stable and efficient extraction effect.Taking Xiagou Coal Mine as research object, numerical simulation and field verification methods were used to determine dominant gas extraction area of high-level boreholes in ZF302 coal face, and its distribution law was studied. The research results show that the dominant gas extraction area of high-level boreholes in ZF302 coal face is located in the area with vertical height of roof of 33-57 m. In the dominant gas extraction area, the gas extraction volume of single hole shows a trend of first increasing, then becoming stable, and then decreasing. When the height of the final hole is located in the area of 70-57 m, the gas extraction volume of single hole gradually increases from 0.66 m3 /min to 1.48 m3 /min, and then enters the stable area within the height of 57-34 m, and the gas extraction volume of single hole always keeps above 1.0 m3 /min.When the position of the final hole of high-level boreholes is located in the vertical height of 55-65 m, the extraction time of dominant gas extraction area is the longest and the gas extraction quantity of single hole is the highest. After optimization of drilling parameters, the number of boreholes in the drilling field is reduced from 28 to 18, a decrease of 35.71%. The daily extraction volume increases from 26 008.75 m3 to 31 046.4 m3, increasing by 19.37%.

     

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