Study on displacement coalbed methane by carbon dioxide injection

The adsorption-desorption behavior of carbon dioxide and methane gases in coal samples were experimentally studied,a modeling experiment of carbon dioxide displacing CH4 was accomplished.The results indicate that the adsorption of CO2 is prior to that of CH4 and the desorption rate of CH4 at unit pressure drop in the process of carbon dioxide displacement is obviously higher than that in the process of pure CH4 desorption,the coalbed methane desorption rate at unit pressure drop of coal was increased by 77.7%.