Research Article

Non-Darcy Flow in Hydraulic Flushing Hole Enlargement-Enhanced Gas Drainage: Does It Really Matter?

Table 2

Property parameters used in the simulation model.

ParametersValueSource

Young’s modulus of coal (, MPa)850Lab measurement
Poisson’s ratio of coal ()0.35Lab measurement
Initial cohesion of coal (, MPa)0.72Lab measurement
Residual cohesion of coal (, MPa)0.30Lab measurement
Friction angle of coal (, °)32Lab measurement
Coal density (, kg/m3)1375Lab measurement
Temperature of coal (, K)293Field data
Average thickness of coal (, m)1.8Field data
Horizontal principal stress (, MPa)14Field data
Initial coal permeability (, mD)0.0015Field data
Initial porosity of coal ()0.058Lab measurement
Fracture volume compressibility (, MPa−1)0.045Lab measurement
Initial gas pressure (, MPa)2.5Field data
Equivalent plastic shear strain from which the residual behavior starts ()0.012Lab measurement
Molar mass of methane (, g/mol)16Specified value
Molar volume of methane at the standard condition (, L/mol)22.4Specified value
Dynamic methane viscosity (, Pa·s)Specified value
Universal gas constant (, J/(mol·K))8.41351Specified value
Langmuir pressure (, MPa)1.32Lab measurement
Langmuir volume (, m3/t)22.5Lab measurement
Sorption time (, d)0.52Lab measurement
Langmuir volumetric strain constant ()0.0038Lab measurement
Cleat volume compressibility (, MPa−1)0.045Lab measurement