Rittershoffen, France

This EGS project, called ECOGI, is located in Northern Alsace within the Upper Rhine Graben. It is planned to produce geothermal steam to dry starch in a bio-refinery located close to the Rhine River. This geothermal project aims to exploit hot fluids (> 160 °C) at around 2 600 m depth at the cover-basement unconformity. Two deep boreholes (2.6 km deep) have been drilled for intersecting deep Triassic sandstone lying on fractured crystalline rocks. Due to a low natural injectivity index, the first well GRT-1 has been chemically and hydraulically soft stimulated. In this injection well, poststimulation injectivity was improved by a factor 5 leading to industrial flow rate higher than 70 L/s. Moreover, this soft stimulation program was carried out with no environmental nuisances. First, there was no induced seismicity event felt during hydraulic stimulation. Second, environmental free chemicals were used for dissolving specifically hydrothermal minerals sealing the pre-existing fractures. After those encouraging stimulation results, a second borehole has been drilled at Rittershoffen for targeting a production well which was quite successful with artesian flow conditions (> 40 L/s) at high temperature (> 160 °C). Thus, future operational hydraulic conditions with production flow rates higher than 70 L/s can be expected. As those soft stimulation data were never published and belong now ESG, it is planned to deeply interpret them in the framework of the DESTRESS project.

Operator operator-logo

és Géothermie

Work Package No



Rittershoffen, France

Construction Year

2 wells finished and stimulated in 2014

Foreseen Stimulation Techniques stimulation-logo

THMC-Stimulation techniques performed 2013
Evaluation within DESTRESS

Type of Use

Heat for (green) chemical industry

Soil Condition

Fractured clastic rocks (SS) and fractured granite with high temperature geothermal resources

Production Horizon

Fractured Triassic sandstone and Carboniferous fractured granite

Upper Depth (m)


Thickness (m)


T (°C)


Salinity (g/l)



Dr Albert GENTER, Deputy General Manager
26, bld Wilson,
67000 Strasbourg, France

Phone: +33 (0)3 88 20 72 88
E-mail: albert.genter@es.fr