冷冻取心测定煤层瓦斯含量的可靠性研究

    Reliability of determination of gas content in coal seam with freezing coring

    • 摘要: 为了考察冷冻取心技术在煤层瓦斯含量测定中的可靠性及优势,采用试验和理论分析相结合的方法,通过自主研发的含瓦斯煤冷冻取心模拟试验装置开展了系列取样深度(20、30、40、50 m)条件下的冷冻取心过程及常规取心过程的煤样瓦斯解吸试验,得到了常规取心和冷冻取心过程在各个条件下的瓦斯解吸参数(解吸量、解吸速度)随时间的变化数据,并对数据进行了深入分析。研究结果表明:在不同取样深度下,冷冻取心过程中煤心样瓦斯解吸量变化分为前期快速增加、短暂稳定、中期减少和后期稳定阶段;冷冻取心过程中煤心瓦斯解吸速度变化分为快速衰减和缓慢衰减阶段,最后趋向于0;不同取样深度下,冷冻取心比常规取心的解吸量降低了77%~88%。

       

      Abstract: Coal seam gas content is one of the most important basic parameters in coal mine, and its accurate determination is very important for coal mine safety mining and coal seam gas exploration or development. In order to investigate the reliability and advantages of freezing coring technology which is usually used to determine the coal seam gas content, the gas desorption test under different sampling depths(20 m, 30 m, 40 m, 50 m) within conventional coring and freezing coring were conducted respectively. We got the gas desorption parameters(gas desorption amount, gas desorption rate) change data versus time, then we combined with theoretical knowledge to conduct an in-depth analysis of these data. The results show that: the change of coal sample gas desorption volume at different sampling depths during freezing and coring can be divided into the early stage of rapid increase, the short-term stability, the mid-term decrease, and the later stage of stability; the change of coal core gas desorption rate during the freezing core process can be divided into rapid decrease stage and slow decrease stage which finally tends to 0; freezing coring reduces the gas desorption capacity by 77% to 88% compared with conventional coring at different sampling depths.

       

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