Characterization of Permeability Changes in Coal of High Rank during the CH₄-CO₂ Replacement Process

Table 3

Contrasting results of the decreasing value of permeability caused by increasing effective stress on the HA and HB coal specimens.

Injection gas balanced pressures (MPa)	Relationships between effect stress and permeability		Decreasing values of permeability (mD)
	HA coal	HB coal	HA coal	HB coal
1.25			0.180	0.107
2.25			0.119	0.067
3.25			0.166	0.091
4.25			0.174	0.086
5.25			0.172	0.096
6.25			0.154	0.081