Abstract:

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.

Key words:

CO2 gas phase fracturing, coal seam gas, extraction radius