摘要
为了提高现实瓦斯抽采效率问题,针对平煤股份十矿24080工作面瓦斯赋存情况以及煤岩体的力学特性考虑影响瓦斯抽采效果的因素,采用单一变量法对抽采瓦斯的时间、负压、钻孔直径、钻孔间距影响抽采效率参数进行模拟研究,利用COMSOL多物理场模拟软件设置煤岩体固体力学和达西定律瓦斯渗流模块构建流固耦合模型并进行数值模拟研究。结果表明:通过1~180 d的瓦斯压力云图变化得到瓦斯抽采效果与时间呈现正相关的关系;在负压为15~25 kPa的范围进行间隔5 kPa梯度模拟,通过瓦斯压力云图等值圈及其重叠面积大小判断,改变抽采负压不仅能够一定程度上加速单孔瓦斯抽采速率,也能够使相邻钻孔产生促进抽采的扰动,在合适的扰动下能够改善瓦斯抽采效果;在钻孔直径为75 mm、95 mm、115 mm、150 mm时,对应的有效抽采半径分别为1.57 m、1.68 m、1.81 m、1.87 m.相邻设置钻孔之间的有效抽采相应增大0.11 m、0.13 m、0.06 m.说明在一定程度内钻孔直径越大,越有利于瓦斯抽采,但考虑到钻孔成型后,其受到地应力和开采扰动等影响,较大的孔径更易发生变形或塌孔,不利于瓦斯抽采;通过1 m、2 m、3 m的钻孔间距设置与分析抽采30 d时的多孔抽采瓦斯煤层瓦斯压力分布规律得到瓦斯压力下降程度指标,当压力下降超过50%认为该区域是强影响区,在此条件下的钻孔间距设计较为经济合理。
In order to improve the actual gas extraction efficiency,in view of the gas occurrence in No.24080 working face and the mechanical characteristics of coal and rock mass,the factors affecting the gas extraction efficiency were considered,the single variable method is used to simulate the effect of time,negative pressure,bore diameter and bore spacing on gas extraction efficiency,the fluidsolid coupling model was established by using COMSOL software to simulate the solid mechanics of coal and rock and the gas seepage module of Duthie's law.The results show that the relationship between gas extraction efficiency and gas extraction time is positive through 1~180 d gas pressure cloud map changes,and 5 kPa gradient simulation is carried out in the range of negative pressure 15~25kPa,according to the equivalent circle of gas pressure cloud graph and the size of its overlap area,changing the negative pressure of gas extraction can not only accelerate the gas extraction rate of single hole to a certain extent,but also cause the disturbance of adjacent boreholes to promote gas extraction,when the diameter of borehole is 75 mm,95 mm,115 mm,150 mm,the corresponding effective extraction radius is 1.57 m,1.68 m,1.81 m,1.87 m respectively.The effective pumping between adjacent boreholes increases by 0.11 m,0.13 m,0.06 m respectively.It shows that the larger the diameter of the borehole is,to some extent,more favorable to gas extraction,but considering that after the borehole is formed,it is affected by in-situ stress and mining disturbance,the larger the diameter of the borehole is more likely to deform or collapse,through setting the interval of 1 m,2 m and 3 m boreholes and analyzing the gas pressure distribution law of multi-hole gas extraction coal seam in 30 d,the index of gas pressure drop degree is obtained,when the pressure drop is more than 50%,the area is considered to be a strong influence area.
作者
张孟浩
寇杰
陈菲
ZHANG Menghao;KOU Jie;CHEN Fei(College of Coal Engineering of Shanxi Datong University,Datong 037003,China;Yiyang Education Consulting Co.,Ltd.,Xuzhou 221000,China)
出处
《煤》
2024年第5期10-17,共8页
Coal
基金
国家自然科学基金资助项目(51274113)
国家重点研发计划重点专项资助项目(2018YFC0807900)
山西大同大学博士启动金资助项目(2020-B-18,2020-B-08)。
