Analysis of Gas Content and Permeability Change Pattern of a Coal Reservoir in the Tectonic Positions Based on a THM Coupled Model

Table 4

Main parameters of 1302 coal mining face modeling.

Parameter name	Variables	Numerical value	Unit
Coalbed gas dynamic viscosity coefficient			Pa-s
Initial porosity of the coal seam		0.0792	/
Rock modulus of elasticity		30,000	MPa
Modulus of elasticity of the coal matrix		14000	MPa
Coal Poisson’s ratio		0.27	/
Coefficient of volumetric thermal expansion of coal			m^3/(m^3-K)
Working surface gas pressure		0.1	MPa
Working surface boundary temperature		293	K
Langmuir pressure constants		3.87	MPa
Langmuir volume constants		6.73	cm^3/g
Density of coal		1400	kg/m^3
Rock density		2300	kg/m^3
Normal gas constants		8.3143	J/(mol-K)
Molar volume of coalbed methane		0.0224	m^3/mol
Initial penetration rate			m^2
Ash		0.1622	/
Moisture		0.0835	/
Coal seam gas pressure at standard condition		0.10	MPa
Coalbed gas density at standard condition		0.717	kg/m^3
The bulk modulus of solid particles			Pa
Pore fractal dimension		2.776	/