Analysis of Thermo-Hydro-Mechanical Coupling of Coal and Gas with Absorption/Desorption Thermal Effect

Table 4

The parameters used for gas migration in coal seam.

Variable	Parameter	Value	Unit
	Young’s modulus of coal	2.56 × 10^3	MPa
	Poisson’s ratio of coal	0.12
	Density of coal	1400	kg·m^−3
	Universal gas constant	8.3143	J·mol^−1 K^−1
	Gas molar volume	22.4 × 10^−3	m^3·mol^−1
	Initial porosity of coal	0.0436
	Initial permeability of coal	1.77 × 10^−18	M^2
	Initial temperature	292.4	K
	Initial gas pressure of coal	1.3	MPa
	Methane dynamic viscosity	1.087 × 10^−5	Pa·s
	Density of gas at standard condition	0.717	kg·m^−3
	Pressure at standard condition	0.101325	MPa
	Langmuir’s volume constant	0.03476	m^3·kg^−1
	Langmuir’s pressure constant	0.6521	MPa
	Temperature at standard condition	273	K
	Volumetric thermal expansion of the solid matrix coefficient	0.000116	K^−1
	Thermal conductivity of coal particles	0.443	J·m^−1·s^−1 K^−1
	Specific heat capacity of gas	2.16	kJ·kg^−1 K^−1
	Specific heat capacity of coal	1.26	kJ·kg^−1 K^−1