| matrix width, a (m) |
0.01 |
Langmuir constant of CH4-induced strain, εL1
|
0.0128 |
| fracture aperture, b(m) |
0.0002 |
Langmuir constant of CO2-induced strain, εL2
|
0.0237 |
| initial permeability of
the matrix, km0 (m2) |
1 × 10–17
|
Langmuir volume constant
of CH4, VL1 (m3/kg) |
0.0256 |
| initial permeability of
the fracture, kf0 (m2) |
1 × 10–14
|
Langmuir volume constant
of CO2, VL2 (m3/kg) |
0.0477 |
| porosity of the matrix, ϕm0
|
0.045 |
Langmuir pressure constant
of CH4, PL1 (MPa) |
2.07 |
| porosity of the fracture, ϕf0
|
0.011 |
Langmuir pressure constant
of CO2, PL2 (MPa) |
1.38 |
| density of coal, ρs (kg/m3) |
1.47 × 103
|
initial water saturation, Sw0
|
0.82 |
| bulk modulus
of the matrix, Km (Pa) |
1.2 × 1010
|
irreducible water saturation, Swr
|
0.42 |
| bulk modulus of the fracture, Kf (Pa) |
1.5 × 108
|
residual gas saturation, Sgr
|
0.05 |
| Young’s
modulus of
coal seam, E (GPa) |
4 |
dynamic viscosity of CH4, μ1 (Pa·s) |
1.34 × 10–5
|
| temperature, T (K) |
338.8 |
dynamic viscosity of CO2, μ2 (Pa·s) |
1.84 × 10–5
|
| coefficient, η |
1 |
dynamic viscosity of water,
μw (Pa·s) |
1.01 × 10–3
|
| Klinkenberg factor, bk (MPa) |
0.76 |
diffusion
coefficient of
CH4, D10 (m2/s) |
3.6 × 10–12
|
| entry capillary pressure, pe (MPa) |
0.1 |
diffusion coefficient
of
CO2, D20 (m2/s) |
5.8 × 10–12
|
| capillary pressure model:
coefficient, λ |
2 |
relative permeability
model
coefficient, m
|
0.6 |
| Poisson’s ratio,
ν |
0.35 |
In situ stress of reservoir,
σ (MPa) |
6 |
