Study on permeability evolution and damage mechanism along the EGS fracture in heat mining stage under thermal stress/cracking

Geothermal Energy

Science – Society – Technology

Table 3 Model boundary and initial condition

Parameters	Symbol	Value	Unit
Initial temperature of hot rock	T₀	200	℃
Temperature of the fracturing fluid	T_inj	20	℃
Injection pump rate	U_inj	5/10	mL/min
Heat transfer coefficient between fluid and rock	h	4000	W/(m² K)
Confining pressure	σ_h	20/25	MPa
Heterogeneity of physical and mechanical parameter	m	10/30	/
Fracture width	d_fr	1	mm
Fracture permeability	k_fr	3 × 10^–12	m²
Matrix permeability	k_m	5 × 10^–18	m²