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.