Experimental research on displacing coal bed methane with supercritical CO2

The high-gas and low-permeability are the common problems of China coal mine, which restrain the mining of coal-seam gas resources safely and efficiently. Hence, to solve the problem of low permeability of coal seam, an experimental system was set up and experimental research was conducted to investigate the effect of the displacement of methane by injecting supercritical CO2 into coal samples. The experimental results indicated that, the extraction effect of supercritical CO2 changes the coal’s porosity, and broadens the seepage channel for methane. Thus, the methane could be desorbed effectively from the coal matrix, and flow through more cracks at higher speed.

► To improve the permeability of coal-bed, an experimental system was set up.
► The effect of displacement of coal-bed methane by supercritical CO2 was studied.
► The extraction broadens the seepage channel for coal-bed methane.
► The permeability of coal sample increased after the extraction of supercritical CO2.