摘要
为使瓦斯抽采效果在技术、经济方面达到最佳,研究了瓦斯抽采过程中煤层瓦斯的运移规律和钻孔的合理布孔间距。将煤层视为双孔隙双渗透率弹性介质,推导了煤基质、裂隙渗透率演化方程,综合考虑了瓦斯吸附/解吸特性、煤岩变形等因素的影响,建立了煤层双重介质流固耦合模型,并进行了钻孔瓦斯抽采模拟,分析了钻孔间距对瓦斯抽采的影响。结果表明：不同钻孔间距的瓦斯压力随抽采时间的增加先快速下降再趋于平缓,且钻孔间距越小,瓦斯压力下降越快;随着钻孔间距的增大,O点消突时间逐渐增加,与钻孔间距呈二次方关系;现场试验与模拟结果基本吻合,钻孔间距5 m时瓦斯抽采效果最佳。
The paper intends to pursue the gas migration law and the reasonable allocation among the boreholes through a numerical simulation and the on-spot test. Different from the general opinion to take the coal seam as an elastic medium with the single permeability,the present author prefers to take it as a kind of elastic medium with the dual porosity and permeability,including the coal matrix permeability and the fracture permeability,so as to deduce the dynamic evolution equations of the coal matrix,fracture porosity and permeability. Thus,it may allow us to establish a hydraulic-mechanical coupling model of the dual media in the coal seam through the study of the gas adsorption and desorption and taking into account the coal rock deformation factors and the two-phase flow nature. While studying the numerical simulation of borehole gas extraction,we have also analyzed the influence of boreholes spacing on the gas extraction. The simulation results of ours show that： First of all,the gas pressure of the different boreholes spacing at first tends to decline quickly and then comes to get stabilized with the increase of the extraction time. Therefore,the closer the borehole is,the more quickly the gas pressure tends to drop down. Secondly,with the increase of the boreholes spacing,the outburst elimination time of point O may tend to increase gradually in a square relation with the interpolation of the boreholes. Thus,it can be found that the effect of the gas extraction tends to be optimistic when the average interpolation distance reaches 5 m. In so doing,it would be possible to get rid of the blind area of extraction and achieve effective gas extraction and economize engineering input. The status-in-situ testing results here displayed prove to be basically consistent with that of the said simulation and also conform the reliability and availability of the hydraulic-mechanical coupling model with the dual porosity and dual permeability,thus,providing a faithfulness of the design approach to the gas extraction.
作者
李胜
张浩浩
范超军
陶梅
LI Sheng;ZHANG Hao-hao;FAN Chao-jun;TAO Mei(College of Mining engineering,Liaoning Technical University,Fuxin 123000,Liaoning,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2018年第4期1284-1289,共6页
Journal of Safety and Environment
基金
国家重点研发计划项目(2016YFC0801407)
国家自然科学基金项目(51674132)
辽宁省教育厅城市研究院项目(LJCl002)
关键词
安全工程
瓦斯抽采
双重介质
流固耦合
钻孔间距
safety engineering
gas extraction
dual medium
hydraulic-mechanical coupling
boreholes spacing
作者简介
李胜,教授，博士生导师，从事矿山压力与矿井动力灾害防治研究，lisheng76@139．com。
