长钻孔远距离定点瓦斯含量测定研究

Study on long drilling long-distance fixed-point gas content measurement

  • 摘要: 针对定向长钻孔定点取样测定瓦斯含量存在取样时间长,因现场无解吸量而无法准确测定煤层瓦斯含量的问题,提出采用类比法推算取样过程瓦斯损失量和常压瓦斯解吸量的方法。在相同地质条件和瓦斯地质单元内,将普通回转钻机浅孔风排粉取样瓦斯含量测定结果中的损失量和现场瓦斯解吸量占总瓦斯含量的比例作为标准,类比为千米定向钻孔深孔定点取样损失量和现场解吸量占总瓦斯含量的比例,将类比的损失量和现场解吸量所占的比例加入最终所测定的残余瓦斯含量中,得到千米定向钻机深孔定点取样总瓦斯含量。将该方法用于平煤十一矿己16-17-24070工作面长钻孔瓦斯含量测定,对千米定向钻孔取样瓦斯含量测值进行修正。测试结果表明,运用类比法修正过的长钻孔瓦斯含量测值与短钻孔直接法测定的瓦斯含量测值对比,平均误差由12.07%降至0.19%;运用类比法修正过的长钻孔瓦斯含量测值与瓦斯含量预测值对比,平均误差由12.90%降至4.71%。

     

    Abstract: The sampling time of long drilling fixed-point gas content measurement is long. And it is unable to measure the gas content in coal seams accurately due to the absence of desorption on site. In order to solve the above problems, a method of using analogy to estimate gas loss and atmospheric gas desorption during sampling is proposed. In the same geological conditions and gas geological unit, the ratio of gas loss and on-site gas desorption to the total gas content in the measurement results of the gas content of the shallow drilling air exhaust powder sampling of the common rotary drilling rig is used as the standard. The analogy is the ratio of gas loss and on-site gas desorption to the total gas content in the deep drilling fixed-point sampling of the kilometer directional drilling rig. The ratio of gas loss and on-site gas desorption is added to the final measured residual gas content. The total gas content of the deep drilling fixed-point sampling of the kilometer directional drilling rig is obtained. This method is used to measure the gas content of long drilling in the Ji16-17-24070 working face of No.11 Pingdingshan Coal Mine, and to correct the gas content measured values of the kilometer directional drilling sampling. The test results show that compared with the gas content measurement of the short drilling direct method, the average error of the long drilling gas content measurement corrected by the analogy method is reduced from 12.07% to 0.19%. Compared with the content prediction values, the average error of the long drilling gas content measured values corrected by analogy method is reduced from 12.90% to 4.71%.

     

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