Dynamic Characteristics of Offshore Natural Gas Hydrate Dissociation by Depressurization in Marine Sediments

Table 1

The main experimental parameters and independent variables obtained for offshore NGH dissociation.

Physical variables	Values
Porosity	0.305
The intrinsic permeability (μm^2)	0.45
Initial saturation of NGH	0.63
Initial saturation of water	0.21
Initial saturation of natural gas	0.68
Specific heat of ice (J·kg^-1·K^-1)	2105
Specific heat of NGH (J·kg^-1·K^-1)	1795
Specific heat of marine sediment (J·kg^-1·K^-1)	850
Specific heat of water (J·kg^-1·K^-1)	4215
Thermal conductivity of ice (W·K^-1·m^-1)	3.45
Thermal conductivity of NGH (W·K^-1·m^-1)	0.50
Thermal conductivity of natural gas (W·K^-1·m^-1)	0.07
Thermal conductivity of water (W·K^-1·m^-1)	0.60
Initial temperature (K)	281.4
Temperature at the bottom of the wellbore (K)	281.4
Initial pressure (MPa)	5.82
Density of ice (kg·m^-3)	902
Density of NGH (kg·m^-3)	910
Density of marine sediment (kg·m^-3)	2500
Density of water (kg·m^-3)	1010
Viscosity of natural gas (mPa·s)	0.01
Viscosity of water (mPa·s)	1.0