The influence of hydrothermal brine on the short-term strength and elastic modulus of sandstones from exploration well EPS-1 at Soultz-sous-Forêts (France)

Geothermal Energy

Science – Society – Technology

Table 6 Summary of the average ratios of water-saturated-to-dry, brine-saturated-to-dry, and water-saturated-to-brine-saturated strengths and static elastic moduli for the six sandstones sampled from exploration well EPS-1 at the Soultz-sous-Forêts geothermal site (France)

Sample box number	UCS wet/UCS dry	UCS brine/UCS dry	UCS wet/UCS brine	E wet/E dry	E brine/E dry	E wet/E brine
84	0.62	0.65	0.95	0.81	0.92	0.88
100	0.73	0.87	0.83	0.83	0.96	0.87
157	0.64	0.61	1.04	0.84	0.81	1.03
198	0.75	0.66	1.13	0.91	0.90	1.02
402	0.76	0.82	0.93	0.89	0.90	0.98
540	0.67	0.70	0.96	0.86	0.93	0.92
Melbourne sandstone (S-type) (Shukla et al. 2013)	0.39	0.37	1.05	–	–	–
Melbourne sandstone (M-type) (Shukla et al. 2013)	0.76	0.63	1.22	–	–	–
Gosford sandstone (Rathnaweera et al. 2014)	0.64	0.58	1.10	–	–	–

The UCS of the brine-saturated samples taken from Shukla et al. (2013) and Rathnaweera et al. (2014) correspond to the salt concentration closest to that tested herein (NaCl 10%)
UCS uniaxial compressive strength, E static elastic modulus