Experiment Study On Gas Sorption,gas Percolation And Gas Injection Displacement Of Bituminous Coal In Xutuan Mine

The research of gas storage characteristic in coal seam is is an important research foundation for extraction of coal and gas together.Gas injection displacement is an important measure to promote gas extraction.The study of coal gas sorption and seepage not only helps explain the mechanism of gas injection,but also provides important basic cognition for extraction of coal and gas together.This paper takes Anhui province Xutuan coal mine coal samples as the research object,the experiment study of coal gas sorption,coal gas seepage and gas injection was carried out,and the relevant research results were obtained.（1）The isothermal sorption experiments of bituminous coal sample to pure gases were carried out.And the adsorption capacity of three kinds of gas in bituminous coal is CO₂>CH₄>N₂.The fitting analysis indicates that the fitting effect of Langmuir equation and DR equation is better than that of BET equation.（2）The isothermal adsorption experiments of bituminous coal sample to CO₂-CH₄ mixture were carried out.It is found that displacement and competitive adsorption had the same final adsorption capacity and the total adsorption capacity of multi components is between the one component carbon dioxide adsorption capacity and the methane adsorption amount.Based on the Langmuir parameters,the E-L equation can predict the adsorption capacity of the mixed gas properly.（3）The mechanical analysis of fluid solid coupling coal is carried out,and the control factors of the permeability experiment are determined.The influence of pore pressure to permeability mainly attributes to the Klinbenberg effect.The increase of effective positive stress resulted that the compression of the coal skeleton,and finally decreased the permeability.Both the direction and size of the effective shear stress will have an impact to the gas permeability.（4）The comparison experiment of free desorption and gas injection showed that gas injection released more methane than free desorption,and the increase of displacement pressure helps to release more methane.When gas injection works as an auxiliary means to promote gas drainage,this thesis suggests injecting compressed air into the coal seam to improve the drainage effect.