Anthracite in Jincheng is a highly metamorphic coal and its system of fissures and pores is differentfrom that of low and medium ranked coal.In order to discover their characteristics,69 samples were collected from 18...Anthracite in Jincheng is a highly metamorphic coal and its system of fissures and pores is differentfrom that of low and medium ranked coal.In order to discover their characteristics,69 samples were collected from 18 CBM wells in Zhengzhuang in Jincheng and their fissures and pores were observed by a Scanning Electron Microscope(SEM).To the naked eyes and by SEM,the pores in the Jincheng anthracite are seen to have abundant mold pores with isolated,shallow and poor connectivity(diameters between 1～50 μm) and few plant tissue pores,gas pores,and solution pores.Most of the fissures are filled with clay minerals or closed;while open fissures are not often visible in the Jincheng coal(aperture between 3～10 μm).These characteristics are determined by the high rank and high vitrinite content of the coal.The existence of too many mold pores and filled fissures does not allow the migration of methane,hence hydraulic fracture stimulation will be required and is an effective method of adding and connecting fissures to enhance CBM production.展开更多
A gas migration controlling equation was formulated based on the characteristics of the dual pore–fracture media of coal mass and in consideration of the matrix exchange between pores and fractures.A model of permeab...A gas migration controlling equation was formulated based on the characteristics of the dual pore–fracture media of coal mass and in consideration of the matrix exchange between pores and fractures.A model of permeability dynamic evolution was established by analyzing the variation in effective stress during gas drainage and the action mechanism of the effect of coal matrix desorption on porosity and fracture in the coal body.A coupling model can then be obtained to characterize gas compressibility and coal deformability under the gas–solid coupling of loading coal.In addition,a 3D model of boreholes was established and solved for gas drainage based on the relevant physical parameters of real mines.The comparison and analysis results for the law of gas migration and the evolution of coal body permeability around the boreholes before and after gas extraction between the dual media and the single-seepage field models can provide a theoretical basis for further research on the action mechanism of gas drainage.展开更多
基金supported by the National Basic Research Program of China (No.2006CB202200)
文摘Anthracite in Jincheng is a highly metamorphic coal and its system of fissures and pores is differentfrom that of low and medium ranked coal.In order to discover their characteristics,69 samples were collected from 18 CBM wells in Zhengzhuang in Jincheng and their fissures and pores were observed by a Scanning Electron Microscope(SEM).To the naked eyes and by SEM,the pores in the Jincheng anthracite are seen to have abundant mold pores with isolated,shallow and poor connectivity(diameters between 1～50 μm) and few plant tissue pores,gas pores,and solution pores.Most of the fissures are filled with clay minerals or closed;while open fissures are not often visible in the Jincheng coal(aperture between 3～10 μm).These characteristics are determined by the high rank and high vitrinite content of the coal.The existence of too many mold pores and filled fissures does not allow the migration of methane,hence hydraulic fracture stimulation will be required and is an effective method of adding and connecting fissures to enhance CBM production.
基金supported by Chinese Ministry of Education (No.213022A)the National Natural Science Foundation of China (No.51574112)+4 种基金Henan Key Laboratory of Biogenic Traces and Sedimentary Minerals (No.OTMP1410)the Key Research Project of Higher Education Institution of Henan Province in 2015 (No.15A440001)the Doctor Funds of Henan Polytechnic University (No.B2015-05)the Basic and Advanced Technology Research Projects of Henan Province (No.162300410031)the Science and Technology Innovation Funds for Distinguished Young Scholar in Henan Province (No.164100510013)
文摘A gas migration controlling equation was formulated based on the characteristics of the dual pore–fracture media of coal mass and in consideration of the matrix exchange between pores and fractures.A model of permeability dynamic evolution was established by analyzing the variation in effective stress during gas drainage and the action mechanism of the effect of coal matrix desorption on porosity and fracture in the coal body.A coupling model can then be obtained to characterize gas compressibility and coal deformability under the gas–solid coupling of loading coal.In addition,a 3D model of boreholes was established and solved for gas drainage based on the relevant physical parameters of real mines.The comparison and analysis results for the law of gas migration and the evolution of coal body permeability around the boreholes before and after gas extraction between the dual media and the single-seepage field models can provide a theoretical basis for further research on the action mechanism of gas drainage.
