Research status on direct measurement and sampling technology for coal seam gas content

Accurate measurement of coal seam gas content is the premise of coal mine gas disaster prevention and control, the development of "real" sampling technology is the key to accurately measure coal seam gas content.Based on the previous study and literature research, this paper reviews the development process of measurement and sampling technology for coal seam gas content in underground coal mines, analyzes the principle, technical characteristics, applicable conditions in engineering application and key problems of the representative technology of direct measurement and sampling of underground coal seam gas content in China. The deep-hole fixed-point sampling technology solves the problems of sampling time, sampling granularity and insitu sampling of coal samples. Long-distance sealed coring technology meets the needs of advanced and accurate gas detection and regional gas extraction effect evaluation for long-distance one-hole multiple measurements, low-temperature freezing sampling technology inhibits the temperature influence of gas desorption in coal samples.Looking forward to the development trend of direct measurement and sampling technology for coal seam gas content, it is considered that the development of visual sampling, real-time temperature control and pressurization sampling can reduce the measurement error, the necessity of tackling key scientific problems with insitu measurement technology in drilling is put forward.