Numerical Simulation and Sensitivity Analysis of CO2 Injection Displacement Gas Extraction in Coal Seam
Coal seam gas injection displacement extraction is an effective measure to reduce the gas content of coal seam.In order to explore the influence factors and their sensitivity on the effect of CO2 injection displacement gas extraction in coal seam,the control variable method and orthogonal test method were used to analyze the law of CO2 injection displacement gas extraction in coal seam by using COMSOL Multiphysics numerical simulation software.The sensitivity analysis was carried out on the factors affecting the effect of displacement gas extraction,such as gas injection pressure,coal temperature,coal permeability and coal load.The results show that the increase of gas injection pressure and permeability plays a strengthening role in displacement.The increase of coal temperature and load plays a weakening role in displacement.The sensitivity of the influencing factors of displacement gas volume is ranked as coal permeability＞gas injection pressure＞coal temperature＞load.The effect of coal permeability on displacement gas volume is 5.97 times that of gas injection pressure.The gas injection pressure is 14.97 times that of coal temperature,and coal temperature is 1.65 times that of load.The order of displacement velocity sensitivity is coal permeability＞gas injection pressure＞load＞coal temperature.The effect of permeability on displacement velocity is 9.23 times that of gas injection pressure.The gas injection pressure is 32.66 times that of load,and load is 3.20 times that of coal temperature.In order to achieve better displacement effect in practical engineering,it can be considered to improve coal permeability and increase gas injection pressure.
Gas injection displacementSensitivity analysisDisplacement volumeDisplacement velocityNumerical simulation
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