Research Article
The Migration of Coalbed Methane under Mining Pressure and Air Injection: A Case Study in China
Table 1
Numerical model physical parameters.
| | Parameter | Value | Parameter | Value |
| | Coal elastic modulus (MPa) | 2813 | Adsorption pressure constant (MPa) | 2.07 | | Matrix elastic modulus (MPa) | 8439 | Adsorption volume constant (m3/kg) | 0.0256 | | Poisson’s ratio | 0.34 | Adsorption pressure strain | 0.015 | | Coal density (kg/m3) | 1250 | Initial matrix porosity. | 0.05 | | Air density (kg/m3) | 0.717 | Initial matrix permeability | 2.8·10−18 | | Facture stiffness (MPa) | 4800 | Methane diffusion rate (m2) | 3.6·10−12 | | Dynamic viscosity (Pa·s) | 1.84·10−5 | Initial fracture porosity | 0.002 | | Bulk modulus (MPa) | 5400 | Initial fracture permeability | 2.08·10−17 | | Matrix width (m) | 5·10−6 | Initial temperature (K) | 300 | | Frack width (m) | 0.005 | Air diffusion rate (m2) | 5.8·10−12 |
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