Investigation on the CBM Extraction Techniques in the Broken-Soft and Low-Permeability Coal Seams in Zhaozhuang Coalmine

Table 4

Physical mechanics test results of CBM well test.

Name	Elastic modulus/GPa	Poisson’s ratio	Minimum horizontal principal stress/MPa	Maximum horizontal principal stress/MPa	Vertical stress/MPa
Coal seam roof (mudstone)	2.36	0.32	9.84	10.95	13.22
3# (upper hard layer)	0.98	0.35	7.67	8.92	13.31
3# (lower soft layer)	0.85	0.38	7.67	8.92	13.31