• 论文
主办单位:煤炭科学研究总院有限公司、中国煤炭学会学术期刊工作委员会
考虑时效影响的深部煤层瓦斯运移特性
  • Title

    Characteristics of deep coalbed gas migration based on the time-dependent effect

  • 作者

    张雷周宏伟王向宇荣腾龙陈超凡

  • Author

    ZHANG Lei1 ,ZHOU Hongwei2,3 ,WANG Xiangyu1 ,RONG Tenglong1 ,CHEN Chaofan4

  • 单位

    中国矿业大学(北京) 力学与建筑工程学院中国矿业大学(北京) 能源与矿业学院中国矿业大学(北京) 煤炭资源与安全开采国家重点实验室德国亥姆霍兹环境研究中心(UFZ)

  • Organization
    1. School of Mechanics and Civil Engineering,China University of Mining and Technology(Beijing),Beijing  100083,China; 2. School of Energy and Min- ing Engineering,China University of Mining and Technology(Beijing),Beijing  100083,China; 3. State Key Laboratory of Coal Resources and Safety Mining, China University of Mining and Technology(Beijing),Beijing  100083,China; 4. Helmholtz Centre for Environmental Research-UFZ,Leipzig  04318,Ger- many
  • 摘要

    为了考虑长期抽采过程中时间效应对煤体渗透率的影响,结合平均有效应力建立了时间效应和气体解吸效应耦合作用下的深部煤体孔隙率及渗透率演化模型。运用COMSOL Multiphysics对钻孔周围瓦斯运移过程进行了定量计算,结合现场数据对是否考虑时间效应的瓦斯渗流场变化规律进行了对比分析,并对长期抽采过程中深部煤层瓦斯运移规律进行了模拟分析。结果表明:煤层渗透率随瓦斯压力的下降呈指数型上升趋势;考虑时间效应的孔隙率、渗透率模拟结果明显小于未考虑时间效应模型的结果,且随着抽采时间的增长,蠕变本构中的黏弹性元件使得煤体更为致密,深部煤层的时间效应越发明显,考虑时间效应的孔隙率、渗透率模拟结果与未考虑时间效应的结果差值逐渐增大;考虑时间效应的模拟结果与现场数据匹配度较高,更符合深部煤层孔隙率和渗透率的实际演化特征。在同一抽采时刻,随着距钻孔中心距离的减小,渗透率呈现升高的趋势,压力呈现降低的趋势,当模拟抽采时间为1 d时,临近钻孔中心处渗透率较大、瓦斯压力较小;在不同抽采时刻,当抽采时间逐渐增长时,相同位置处的渗透率逐渐增大,瓦斯压力逐渐减小,当抽采时间由1 d增至30 d时,临近钻孔中心处的渗透率增长近1.4倍,瓦斯压力降低近3.8倍,且模型内渗透率与瓦斯压力的演化趋于平衡状态。

  • Abstract
    In order to study the permeability of deep coal seam with time-dependent effect during the long-term extrac- tion process,the improved porosity and permeability model coupling with gas desorption effect and time-dependent effect was developed by incorporating mean effective stress into the gas migration equation. By using COMSOL Mul- tiphysics,the process of gas migration around the borehole was calculated quantitatively. In combination with the field data,the variation law of gas seepage field with or without time-dependent effect was compared and analyzed,and the law of gas migration in deep coal seam during long-term extraction was simulated and analyzed. The results show that coal seam permeability increases exponentially with gas pressure decreasing. The porosity and permeability simulation results considering time-dependent effect are significantly smaller than those without considering the time-dependent effect model,and as the extraction time increases,the viscoelastic elements make the coal body denser in the creep constitutive. With the increase of extraction time,the time-dependent effect of deep coal seam becomes more obvious, and the difference increases gradually between the simulation results of porosity and permeability considering time-de- pendent effect or not. The time-dependent simulation results are in good agreement with the field data and are more in line with the actual evolutionary characteristics. At the same time,as the distance from the center of the borehole de- creases,the permeability shows an increasing trend,while the pressure shows a decreasing trend. When the extraction time is 1 d,the permeability is large and the gas pressure is small near the center of the borehole. At different extrac- tion times,when the extraction time gradually increases,the permeability gradually increases at the same position,and the gas pressure gradually decreases. When the extraction time increases from 1 d to 30 d,the permeability increases by nearly 1. 4 times near the center of the borehole,the gas pressure decreases by nearly 3. 8 times,and the evolution of permeability and gas pressure tends to balance in the model.
  • 关键词

    深部煤体时间效应渗透率模型瓦斯运移

  • KeyWords

    deep coal;time-dependent effect;permeability model;gas migration

  • 基金项目(Foundation)
    国家重点研发计划资助项目(2016YFC0600704);国家自然科学基金资助项目(51674266);中国矿业大学(北京)越崎杰出学者奖励计划资助项目
  • DOI
  • Citation
    ZHANG Lei,ZHOU Hongwei,WANG Xiangyu,et al. Characteristics of deep coalbed gas migration based on the time- dependent effect[J]. Journal of China Coal Society,2019,44(6):1771-1779.
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