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为研究煤层瓦斯解吸过程中煤层温度的演化规律,利用自主研发的多场耦合煤层气开采物理模拟试验系统,开展不同初始瓦斯压力和不同地应力水平下抽采瓦斯的物理模拟试验。研究结果表明:(1)煤层瓦斯解吸吸热导致煤层温度下降,且温度和流量具有很好的相关性,都表现出在抽采初期下降较快,后期下降缓慢,其中温度随时间的下降量符合对数函数关系;(2)距抽采钻孔越近,瓦斯解吸速度及温度下降越快、温度下降量越大,且垂直钻孔方向的温度梯度大于平行钻孔方向的温度梯度;(3)初始瓦斯压力越大,瓦斯解吸速度及煤层温度下降越快、温度下降量越大,而地应力越大,瓦斯解吸速度及温度下降越慢、温度下降量越小,并且初始瓦斯压力对解吸过程中煤层温度的影响效果较地应力更加显著。
In order to study the evolution law of coal seam temperature during coal seam gas desorption, physical simulation experiments of gas drainage under different initial gas pressures and different ground stress levels were carried out by using the multi-field coupled CBM mining physical simulation test system independently developed. The results show that: (1) The desorption of coal seam gas desorption causes the temperature of coal seam to decrease, and the temperature and flow rate have good correlation. Both of them show a rapid decline in the early stage of pumping and a slow decline in the late stage, of which the temperature decreases with time (2) The closer to the drilling hole, the faster the rate of gas desorption and temperature drop, the larger the temperature drop, and the temperature gradient in vertical drilling direction is greater than the temperature gradient in parallel drilling direction; ( 3) The higher the initial gas pressure, the faster the gas desorption rate and coal seam temperature drop, the greater the temperature drop, and the greater the ground stress, the slower the gas desorption speed and temperature drop, the smaller the temperature drop, and the initial gas pressure pair The influence of coal seam temperature during desorption is more significant than that of in-situ stress.