Modeling Binary CO₂/CH₄ Flow through Coal Media

Abstract

CO₂ can be sequestered in coal seams considering the environmental issues. By means of injecting CO₂ into the coal seams, both sequestration of CO₂ and the enhanced recovery of methane inside the coal seam can be realized. One-dimensional simulation regarding the binary CO₂/CH₄ flow in a coal seam core was studied by using an analytical solution method. The simulation results were compared with experimental data by matching the effluent concentrations of CO₂ and CH₄. The transport parameters such as longitudinal dispersion coefficient, retardation factor, and distribution coefficient were determined. It was seen that the amount of CO₂ captured inside the coal sample during binary displacement was much lower than the maximum adsorption capacity of the coal at the same pressure. Then the transport behavior of CO₂ and CH₄ inside the coal seam was simulated. The results of analytical solution were in good agreement with the measured ones within the acceptable error range.

Keywords:

• analytical solution
• CO₂ sequestration
• coal seam
• enhanced coal bed methane

Acknowledgment

Assistance in providing the experimental data by A. R. Kovscek, Stanford University, is gratefully acknowledged.