Effects of Borehole Arrangement on Methane Migration and Implications for High Efficiency Extraction in Intact and Tectonic Combined Coal Seams

Table 2

Numerical simulation schemes.

Case	Thickness of intact coal sublayer (m)	Thickness of tectonic coal sublayer (m)	Permeability of intact coal sublayer (mD)	Permeability of tectonic coal sublayer (mD)	Permeability ratio ()	Thickness ratio ()
1	1.5	2.0	0.02	0.01	2	1.33
2	1.5	2.0	0.02	0.005	4	1.33
3	1.5	2.0	0.02	0.0033	6	1.33
4	1.5	2.0	0.02	0.0025	8	1.33
5	1.5	2.0	0.02	0.002	10	1.33
6	2.0	1.0	0.02	0.005	4	0.50
7	1.8	1.4	0.02	0.005	4	0.78
8	1.2	2.6	0.02	0.005	4	2.17
9	1.0	3.0	0.02	0.005	4	3.00