Coal Seam Gas Parameters Testing and Numerical Simulation Analysis with CO2 Gas Phase Fracturing
The 9#coal seam of Shanxi Formation mined by Wuhushan Coal Mine is a high gas and dif-ficult to extract coal seam.The efficiency of gas extraction during mining is low,which seriously restricts the safe and efficient production of coal mines.In order to explore the suitable CO2 gas phase fracturing gas control technology scheme,the CO2 gas phase fracturing gas parameter test is carried out in the gas control roadway.The test results show that after the gas phase fracturing,the average gas content is reduced from 8.26 m3/t to 7.67 m3/t,which is reduced by 7%.The Langmuir adsorption volume increased from 19.096 9 cm3/g to 20.265 7 cm3/g,an increase of 6.12%.The permeability coefficient of coal seam increased from 0.022～0.027 to 0.780～0.791,which increased by 28～35 times.Based on the test results of gas parameters,a COMSOL Multiphysics fluid-solid coupling model is established to simulate the gas extraction radius be-fore and after gas phase fracturing.The simulation results show that the gas extraction radius of coal seam is greatly improved after gas phase fracturing,and the extraction radius is increased from 0.63 m to 4.13 m af-ter 180 days of extraction,which is increased by 5.56 times.When the extraction time is 6 months,the gas phase fracturing boreholes can be arranged according to the hole spacing of 8 m,and a good gas extraction effect can be obtained.The research results can provide reference for gas control in coal mines with similar conditions.
CO2 gas phase fracturingcoal seam gasextraction radius
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