A Two-Phase Flowback Model for Multiscale Diffusion and Flow in Fractured Shale Gas Reservoirs

Table 1

Model parameters for Barnett shales.

Parameter	Unit	Value	Physical meanings
		0.15	Residual saturation of gas
		0.6	Residual saturation of water
	Pas		Water viscosity
		2	Pore size distribution index
		2	Corey parameter for water
		2	Corey parameter for gas
	MPa	20.34	Initial reservoir pressure
	m	47.2	Fracture half-length
	MPa	3.45	Well pressure
	mD	0.7	Initial permeability in fractured zone
		0.2	Initial porosity in fractured zone
	mD	50	Permeability in hydraulic fracture
		0.25	Porosity in hydraulic fracture
		0.03	Initial porosity in microfracture of matrix
		0.01	Initial porosity in matrix
		14	Number of hydraulic fractures
	MPa	2	Entry capillary pressure
		0.3	Poisson’s ratio of shale
	kg/m^3	2300	Shale density
	MPa	6	Langmuir pressure of gas in shale
	m^3/kg	0.03	Langmuir sorption capacity of shale for gas
		0.9	End-point relative permeability for water phase
		1	End-point relative permeability for gas phase
T	K	352	Reservoir temperature
	m		Aperture of microfracture in matrix
	m		Diameter of pore in matrix
	m	0.003	Hydraulic fracture width