摘要
煤系页岩瓦斯微观解吸机理研究,对煤田区域煤系页岩瓦斯高效安全开采具有重要意义.基于核磁共振(简称NMR)无损检测技术,以典型高瓦斯矿井阜新清河门矿煤系页岩为例,将页岩试样放入低场核磁共振仪夹持器腔体中,通过先吸附,后降低瓦斯压力,模拟煤系页岩瓦斯解吸过程.以核磁共振T2谱幅值积分定量化表征瓦斯解吸量,以核磁共振横向弛豫时间T2均值减小幅度定量化表征煤系页岩孔隙结构收缩变形程度,从微观角度定量研究煤系页岩瓦斯解吸过程中吸附态和游离态瓦斯变化规律.研究结果表明:吸附态和游离态瓦斯核磁共振谱范围可以通过两个横向弛豫时间截止阈值定量划分;吸附态瓦斯量与瓦斯压力符合朗格缪尔等温吸附方程,游离态瓦斯量与瓦斯压力呈线性函数关系;随瓦斯压力降低,煤系页岩微孔隙结构收缩为原孔隙平均半径0.39倍,中-大孔隙结构收缩为原平均孔隙半径0.25倍.
The micro-mechanism study on desorpfion of coal shale gas was important for the safe and efficient exploitation that the coal shale gas in coalfield region. The non-destructive detecting technology based on nuclear magnetic resonance （hereafter referred to as a NMR） was used in experiments. Taking Qing Hemen Mine in Fuxin as the study case, the desorption process was simulated through first adsorption after constantly reduced gas pressure when the sample was placed into the low field NMR instrument. The micro-quantitative trends on the adsorption of shale-adsorbed gas and porous medium-confined gas were characterized by the nuclear magnetic resonance spectrums integrated amplitude which was equivalent to methane quantity. The mean value of the T2 relaxation time was used to quantitatively describe the shrinkage deformation of the average pore radius. From the micro-quantitative perspective, the trends of adsorbed and porous medium-confined gas were studied. Some new understandings were draw： The ranges of T2 spectrum curve for shale-adsorbed gas and free gas can be determined by the two cutoff thresholds.The relationship between adsorbed gas and gas pressure was in accordance with the Langmuir isothermal adsorption equation. The relation between porous medium-confined gas and gas pressure was linear.With the decrement of gas pressure, the average radiuses of the micro-pore structures were shrunk to 0.39 times original, the average radius of the medium-macro pore structures were shrunk to 0.25 times original.
作者
唐巨鹏
田虎楠
马圆
孙胜杰
李卫军
TANG Jupeng TIAN Hunan MA Yuan SUN Shengjie LI Weijun(School of Mechanics and Engineering, Liaoning Technical University, Fuxin 123000, China)
出处
《辽宁工程技术大学学报（自然科学版）》
CAS
北大核心
2017年第3期282-287,共6页
Journal of Liaoning Technical University (Natural Science)
基金
国家重点研发计划(2016YFC0600901)
国家自然科学基金面上项目(51374119)
辽宁省高等学校优秀人才支持计划(LR2015028)
关键词
NMR
煤系页岩
瓦斯解吸
吸附态瓦斯
游离态瓦斯
NMR
coal shale
gas desorption
shale-adsorbed gas
porous medium-confined gas
