An Approximate Solution for Predicting the Heat Extraction and Preventing Heat Loss from a Closed-Loop Geothermal Reservoir

Table 1

Physical parameters for the present calculation (the parameter values for thermal properties of shale are from Eppelbaum et al. [8] and the value of geothermal gradient is from Quick et al. [9]).

Parameter	Value
Wellbore radius, (m)	0.1
Length of vertical well, (m)	2000
Length of horizontal well (m)	3000
Geothermal gradient, A0 (K/m)	0.047
Surface temperature, B0 (°C)	20
Fluid density (Kg/(m^3))	900
Injection rate, Q (m^3/s)	0.05
Injection temperature (°C)	30.0
Fluid specific heat (J/(Kg·K))	4200
Fluid thermal conductivity (W/(m·K))	0.68
Fluid viscosity (Pa·s)	0.0004
Shale thermal conduct (W/(m·K))	1.42
Shale specific heat (J/(Kg·K))	2151
Shale density (Kg/(m^3))	2057