CO2flooding can increase coal bed methane production rate, enhance coal bed methane recovery and store CO2into underground. It has good application prospect for CBM development. This paper analyzes the adsorption-desorption law of mixed gas in the coal during the CO2injection process, as well as the diffusion and seepage law of gas in the coal seam. The sensitivity of factors affecting coal bed methane production is studied and then the coal bed methane production under different conditions is simulated numerically. The results show that methane concentration and coals permeability are the two key factors affecting the output of coal bed gas and their influence on productivity are even more significant than injection pressure and initial pressure. The higher injection pressure, coals permeability and gas concentration, the greater amount of methane the coal reservoirs will yield. When the coals permeability and the gas concentration in coal reservoirs increase, the growth rate of methane production accelerates accordingly.
Simulation of CO2-geosequestration enhanced coal bed methane recovery with a deformation-flow coupled model
