Influence of combination forms of intact sub-layer and tectonically deformed sub-layer of coal on the gas drainage performance of boreholes: a numerical study  

作　　者：Wei Zhao Kai Wang Rong Zhang Huzi Dong Zhen Lou Fenghua An 

机构地区：[1]Beijing Key Laboratory for Precise Mining of Intergrown Energy and Resources,China University of Mining&Technology,Beijing,Beijing,100083,China [2]School of Emergency Management and Safety Engineering,China University of Mining&Technology,Beijing,Beijing,100083,China [3]Flight Technology College,Civil Aviation University of China,Tianjin,300300,China [4]State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University),Jiaozuo,454003,China

出　　处：《International Journal of Coal Science & Technology》2020年第3期571-580,共10页国际煤炭科学技术学报（英文）

基　　金：National Science Foundation of China(Nos.51904311,51874314);Beijing Municipal Natural Science Foundation(8194072);Fundamental Research Funds for the Central Universities(2019QY02);State Key Laboratory Cultivation Base for Gas Geology and Gas Control(Henan Polytechnic University)(WS2019A04).

摘　　要：High concentration and large flow flux of gas drainage from underground coal seams is the precondition of reducing emission and large-scale use of gas.However,the layered occurrence of coal seams with tectonically deformed sub-layers and intact sub-layers makes it difficult to effectively drain gas through commonly designed boreholes.In this study,the gas drainage performance in coal seams with different combinations of tectonically deformed sub-layers and intact sub-layers was numerically analyzed.The analysis results show that the gas drainage curve changes from a single-stage line to a dual-stage curve as the permeability ratios of Zone II(kII)and Zone I(kI)increase,raising the difficulty in gas drainage.Furthermore,a dual-system pressure decay model based on the first-order kinetic model was developed to describe the dual-stage characteristics of pressure decay curves with different permeability ratios.In the end,the simulation results were verified with reference to in-situ drainage data from literature.The research results are helpful for mines,especially those with layered coal seams comprising tectonically deformed sub-layers and intact sub-layers,to choose appropriate gas drainage methods and develop the original drainage designs for achieving better gas drainage performance.

关 键 词：Tectonically deformed coal Pressure decay Permeability Hydraulic flushing boreholes 

分 类 号：TD712.6[矿业工程—矿井通风与安全]