煤层密闭取心瓦斯含量测试技术及其在定向长钻孔中的应用

Study on gas content measurement technology with sealed coal coring and its application in long borehole of directional drilling

为了准确测定煤层瓦斯含量,提出了煤矿井下煤层密闭取心瓦斯含量测试技术。采用高压水流驱动密闭取心装置中的球阀转动,以达到切断煤心并密封煤心的目的,同时采用取心解吸一体化设计,保证煤心在钻割后、退钻、自然解吸全程密闭,最大限度减少煤心瓦斯逸散量。将该技术应用于煤矿井下底抽巷定向长钻孔中,并成功完成了4个密闭取心样品的采集,最大取心深度达到400 m,煤心样品质量满足瓦斯含量测试要求,样品密封效果良好。从同一深度的取心对比测试结果看,密闭取心瓦斯含量测值大于常规取心测值,前者约高于后者19.07%~44.56%。现场试验表明,煤层密闭取心瓦斯含量测试技术可有效提高煤层瓦斯含量测试精度,其在定向长钻孔中的应用充分体现了密闭取心技术在深孔采样测定煤层瓦斯参数方面的突出优势。

In order to accurately determine the content of coal seam gas,a test technology of gas content of sealed coring in coal seam was put forward.The high pressure water was used to drive the ball valve in sealed coring device to cut off and to seal the coal core.The integrated design of coring and desorption was adopted,and then the core of coal was sealed in full process of drilling,removing the drill rods and natural desorption so as to minimize gas emission of coal core.This technology was applied to the directional long borehole in underground mine bottom drainage way,and 4 samples of sealed coring were completed successfully.The maximum coring depth was 400 m.The weight of coal core sample met the requirement of gas content test,and the sealed effect was good.The sealed coring measured value was larger than that of the conventional coring test,and the former was higher than the latter with 19.07%~44.56%.The field test showed that the measurement technology of coal seam sealed coring gas content could effectively improve the measurement accuracy of coal seam gas content.The application in the long directional drilling had the prominent advantage of the closed coring technology in the measurement of gas parameters in the deep-hole sampling.