Criteria and geological setting for the generic geothermal underground research laboratory, GEOLAB

Geothermal Energy

Science – Society – Technology

Table 1 Requirements to be met by EGS according to Garnish (2002) and reservoir parameters of the Soultz-sous-Forêts EGS

	EGS requirement	Soultz 3.5 km reservoir	Soultz 5 km reservoir
Flow rate ( L s⁻¹)	50–100	24	23
Mean wellhead fluid temperature (°C)	150–200	140	157.5
Effective heat exchange area	>2·10⁶ m²	N/A	N/A
Rock volume (m³)	>2·10⁸	About 7·10⁸	About 2.7·10⁹
Hydraulic impedance	<0.1 MPa L⁻¹ s⁻¹	0.06 MPa L⁻¹ s⁻¹ (GPK1, injection)	0.1 MPa L⁻¹ s⁻¹ (GPK1, injection)
		0.06 MPa L⁻¹ s⁻¹ (GPK2, production)	0.05 MPa L⁻¹ s⁻¹ (GPK2, production)
			0.25 MPa L⁻¹ s⁻¹ (GPK3, injection)
			0.25 MPa L⁻¹ s⁻¹ (GPK4, production)
Water loss at the surface	<10 %	0 % (Total reinjection)	0 % (Total reinjection)

Data from the 3500 and 5000 m reservoirs were obtained in 1997 and 2011, respectively (modified after Schill et al. 2015)