(1. State Key Laboratory of Coal Mine Disaster Dynamics and Control，Chongqing University，Chongqing 400044，China；2. State and Local Joint Engineering Laboratory of Methane Drainage in Complex Coal Gas Seam，Chongqing University，Chongqing 400044，China；3. Huadian Electric Power Research Institute，Hangzhou 310030，China)
Abstract：Coal-bed methane (CBM) is an unconventional gas，its exploitation has fully staffed effect and gets more and more national attention. In order to research the evolution of temperature during gas desorption，the physical simulation of CBM drainage under different gas pressure and in-situ stress was determined based on self-developed multi-field coupling test system for CBM drainage. The results showed as follows：(1) During the drainage process，the coal seam temperature decreased because of gas desorption. As a result，temperature and flow had close correlation，which showed that they decreased rapidly in the early stage，and then declined steadily after a period of drainage. Relationships between temperature dropping and time were logarithmic regression；(2) The closer to the borehole the faster temperature dropped at the same time，the temperature gradient of vertical plane was greater than horizontal plane；(3) The larger the gas pressure，the faster temperature dropped and the greater amount it dropped，while the larger in-situ stress and the slower temperature dropped，the smaller amount it dropped. It can be concluded that the effect of temperature on gas pressure was more significant during gas desorption.
2015, Vol. 34 
