Investigation of the Velocities of Coals of Diverse Rank under Water- or Gas-Saturated Conditions for Application in Coalbed Methane Recovery

Table 2

UPVp and UPVs velocity ranges and the mean values of three ranks of coals.

	Water saturation condition (km/s)				Gas saturation condition (km/s)
	UPVp	UPVpmean	UPVs	UPVsmean	UPVp	UPVpmean	UPVs	UPVsmean
Lignite	[1.18, 2.17]	1.86	[1.13, 1.87]	1.57	[0.61, 1.67]	1.22	[0.44, 1.23]	0.90
Bituminite	[1.61, 2.17]	1.95	[1.04, 1.89]	1.59	[0.71, 1.85]	1.34	[0.64, 1.72]	1.07
Anthracite	[1.63, 2.25]	1.93	[1.26, 1.87]	1.58	[1.12, 1.94]	1.61	[0.74, 1.69]	1.21