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

Figure 5

Correlations between Vr_-water and UPVs_-water and between Vr_-gas and UPVs_-gas for (a, b) lignite, (c, d) bituminite, and (e, f) anthracite.

(a)

(b)

(c)

(d)

(e)

(f)