G 1	thermal gradient within the frozen layer (°C/m)
G 2	thermal gradient below the frozen layer (°C/m)
H	permafrost thickness (m)
k	intrinsic permeability (m2)
k rA	aqueous relative permeability (m2)
k rG	gas relative permeability (m2)
k ΘC	thermal conductivity (W/(m·K))
k ΘRD	thermal conductivity of dry porous medium (W/(m·K))
k ΘRW	thermal conductivity of fully saturated porous medium (W(m·K))
k ΘI	thermal conductivity of ice (W/(m·K))
M W	cumulative mass of produced water (kg)
P	pressure (Pa)
P B	initial pressure at base of HBL (Pa)
P W	pressure at the well (Pa)
Q	total amount of injected heat (J)
q	heat injection rate (W/m of well)
Q P	gas production rate (ST m3/day/m of well)
Q W	water production rate (kg/day/m of well)
r	radius (m)
r W	wellbore radius (m)
R GW	gas-to-water ratio (ST m3 of CH4/m3 of H2O)
S	phase saturation
t	time (days)
T	temperature (°C)
T 0	permafrost ground temperature (°C)
T B	initial temperature at the base of HBL (°C)
V P	cumulative volume of produced CH4 (ST m3)
W	pump work (J)
x,y,z	cartesian coordinates (m)
ΔHC	combustion enthalpy of produced methane (J)
ΔlI-P	horizontal distance between injector and producer (m)
ΔlP-P	vertical distance between two producers (m)
Φ	porosity
η	energy ratio
χ	hydrate dissociation percentage
λ	van Genuchten exponent—Table 1
Subscripts and Superscripts
0	denotes initial state
A	aqueous phase
B	base of HBL
cap	capillary
G	gas phase
H	solid hydrate phase
I	solid ice phase
irA	irreducible aqueous phase
irG	irreducible gas
n	permeability reduction exponent—Table 1
n G	gas permeability reduction exponent—Table 1
W	well