Rational Boreholes Arrangement of Gas Extraction from Unloaded Coal Seam

Table 2

Parameters of gas extraction in the coal seam.

Parameter	Value	Remark
Porosity Φ0	0.055	Experiments
Gas dynamic viscosity μg (Pa·s)	1.03 × 10^−5	Reference [19]
Langmuir pressure constant PL (MPa)	2.45	Experiments
Langmuir volume constant VL (m^3·kg^−1)	0.032	Experiments
Compression coefficient of the coal seam Cp (Pa^−1)	2.39 × 10^7	Experiments
Maximum adsorption strain εmax	0.01266	Reference [20]
Poisson’s ratio ν	0.28	Experiments
Klingberg coefficient b1 (MPa)	0.76	Reference [21]
Coal seam temperature T (K)	315.15	Reference [21]
Strain constant εL	0.0083	Reference [24]
Adsorption strain coefficient γ	52.8	Reference [24]
Adsorption pressure constant P50 (MPa)	5.17	Reference [24]