Research Article
Simulation of the Extraction Efficiency of Coalbed Methane under Water Injection: A Gas-Liquid-Solid Coupling Model
Table 1
Numerical model physical parameters.
| | Parameter | Value | Parameter | Value |
| | Coal elastic modulus /GPa | From Figure 1(a) | Adsorption pressure constant /MPa | 2.07 | | Compressive strength /MPa | From Figure 2(a) | Adsorption volume constant /m3/kg | 0.0256 | | Poisson ratio | 0.34 | Adsorption pressure strain | 0.0102 | | 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 | | Fracture width /m | 0.005 | Water injection pressure /MPa | 2 | | Combined water coefficient | 14.4 | Initial pore water content | 0.02 | | Water density /kg/m3 | 1000 | Water dynamic viscosity /Pa·s | 1·10-3 | | Initial gas saturation | 1 | Initial water saturation | 0 | | VG model | 1.89 | VG model | 0.54 | | VG model | 2.81 | VG model | 0.5 |
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