Effects of diffusion and suction negative pressure on coalbed methane extraction and a new measure to increase the methane utilization rate
Effects of diffusion and suction negative pressure on coalbed methane extraction and a new measure to increase the methane utilization rate
复制标题
扩散吸负压对煤层气抽采的影响及提高瓦斯利用率的新措施
DOI：
10.1016/j.fuel.2017.02.006
复制
发表时间：
2017-06-01
期刊：
影响因子：
7.4
通讯作者：
Hu, Biao
中科院分区：
文献类型：
--
作者：
Dong, Jun;Cheng, Yuanping;Hu, Biao
由于缺乏对扩散和抽吸负压对瓦斯抽放影响的研究，煤矿多采用恒定负压抽放，导致瓦斯浓度和利用率较低。本文利用COMSOL多物理软件对考虑了煤体中拟稳态扩散、裂隙渗流、渗透率演化和煤体变形的气固耦合模型进行了数值求解。模拟结果揭示了甲烷的运移规律和扩散过程对甲烷运移的影响。研究了抽吸负压对瓦斯抽提的作用和影响程度，结果表明，抽吸负压效应随抽放时间的增加而逐渐减弱。结合甲烷运移与漏风的平行关系，计算了不同负压下的甲烷浓度，结果表明，降低负压可以有效地提高甲烷浓度。为改变煤矿瓦斯浓度低、瓦斯利用率低的现状，提出了调整抽放负压、提高瓦斯利用率的成组平行钻孔抽放瓦斯的新技术措施。(C)2017爱思唯尔有限公司。保留所有权利。
A constant suction negative pressure is used in coal mines owing to a lack of research on the effects of diffusion and suction negative pressure on methane extraction, resulting in the low methane concentration and utilization rate. In this study, Comsol Multiphysics is used to conduct a numerical solution of a gas-solid coupling model considering pseudo-steady diffusion in coal matrix, seepage in fractures, permeability evolution and coal deformation. The simulation results reveal the methane migration law and the effect of the diffusion process on the methane migration. The role and the influence degree of the suction negative pressure on methane extraction are studied, demonstrating that the suction negative pressure effect weakens gradually with the increasing methane extraction time. The methane concentrations of different suction negative pressures are calculated considering the changing effects of diffusion and suction negative pressure combined with the parallel relation between the methane migration and the air leakage, indicating that reducing the suction negative pressure can effectively increase the methane concentration. To change the present situation of the low methane concentration and utilization rate in coal mines, a new technical measure of methane extraction through parallel boreholes in groups is proposed to adjust the suction negative pressure and increase the methane utilization rate. (C) 2017 Elsevier Ltd. All rights reserved.