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

Table 5

Fitting and the calculated results of permeability increments under the effect of gas adsorption.

Confining pressure (MPa)	Coal thermal maturity	Fitting results			Permeability decrement (mD)
		a	b	R ^2
6	HA	0.196	0.969	0.652	0.161
8	HA	0.187	0.826	0.617	0.166
8	HB	0.206	1.438	0.852	0.244
10	HA	0.106	0.938	0.657	0.066
12	HA	0.048	5.798	0.977	0.144
12	HB	0.248	0.965	0.742	0.189
14	HA	0.096	1.673	0.867	0.119
16	HB	0.270	0.58	0.423	0.117
20	HB	0.158	1.7	0.791	0.179