1. State Key Laboratory of Coal Mine Disaster Dynamics and Control,Chongqing University,Chongqing　 400044,China;2. Research Institute of Henan Ener-gy Resource and Chemical Industry Group Co. ,Ltd. ,Zhengzhou　 450046,China;3. Yongcheng Coal & Electricity Holding Group Co. ,Ltd. ,Yongcheng　476600,China

利用自主研发的"多场耦合煤层气开采物理模拟试验系统",开展了煤层非均布应力状态下不同钻孔位置条件的煤层瓦斯抽采物理模拟试验,以探讨抽采过程中的瓦斯流动特性及钻孔位置的影响规律和作用机制。对结果进行分析表明:抽采过程中瓦斯压力降低先快后慢,变化形式符合weibull分布函数,温度变化趋势与瓦斯压力基本一致;与钻孔距离越近,瓦斯压力和温度降低越快,瓦斯压力梯度也越大,相反,瓦斯压力梯度则越小;应力集中区对煤层瓦斯流动有一定的屏障作用,不利于气体流动和抽采效率的提高,而渗透系数较高的卸压区有利于瓦斯气体的流动;对拟合所得的Weibull参数分析发现,钻孔位置对瓦斯抽采效率有明显影响,卸压区抽采时位置参数和尺度参数都相对较小,标示着较大的瓦斯压力降低速度和较好地抽采效果,且抽采量也是最大,因此认为采用单一钻孔时,卸压区抽采是相对优化的方式,研究结果对煤层瓦斯抽采提供了参考。

Using a self-developed multi-field coupling testing system for CBM extraction,the physical simulation exper- iments of CBM extraction with different drill hole locations under a non-uniform stress state were carried out,and the gas flow characteristics and the influence law and mechanism with drill hole locations were studied. The results show that gas pressure decreases quickly at the beginning but slowly in the end during CBM extraction,and the variation law is in accord with Weibull distribution function;the variation trend of temperature is consistent with gas pressure. The shorter distance to the drill hole,the faster gas pressure and temperature decrease and the bigger gas pressure gradient is,otherwise the smaller gas pressure gradient is. The stress concentration area seems to hinder gas flow on a certain extent and thus low CBM extraction efficiency,but the pressure relief area which has high permeability is favorable for gas flow. After analyzing the fitted Weibull parameters,the authors canclude that the drill hole locations influence extraction efficiency apparently,location and scale parameters are relatively small when extraction is in pressure relief ar- ea,which suggests a faster gas pressure decrease and more effective extraction,and also the extraction quantity is the biggest. Therefore,when using single drill hole,the extraction in pressure relief area is relatively an optimal method.

国家科技重大专项资助项目(2011ZX05034-004)；强卸荷条件下煤与瓦斯突出动力学演化规律研究资助项目(2011DA105287—MS201302)；重庆市基础与前沿研究计划资助项目(cstc2013jjB90001)；

Wang Weizhong,Liu Dong,Xu Jiang,et al. Experimental study on the influence of drainage borehole position on dynamic parameters of coal seam in CBM recovery process[J]. Journal of China Coal Society,2016,41(2):414-423.