HYDRO-GEOTHERMAL ANALYSES IN THE FIELD OF HOT-DRY-ROCK TECHNOLOGY.

Información del proyecto

Identificador del acuerdo de subvención: EN3G0081

Proyecto cerrado

Fecha de inicio 1 Julio 1986

Fecha de finalización 30 Junio 1989

Financiado con arreglo a

• Research and development programme (EEC) in the field of Non-Nuclear Energy, 1985-1988

Coste total

Sin datos

Aportación de la UE

Sin datos

Coordinado por

Niedersächsisches Landesamt für Bodenforschung
Germany

Objetivo

TO DETERMINE THE THERMAL BEHAVIOUR OF NATURAL AND STIMULATED FRACTURES IN CRYSTALLINE ROCKS IN THE CONTEXT OF GEOTHERMAL HDR DEVELOPMENT.
In a joint German French hot dry rock (HDR) project at Soultz sous Forets the undisturbed temperature field was determined in the borehole GPK 1 in 3 oil wells in the surroundings. The virgin rock temperature is about 140 C at 2000 m depth. The measurements show that the temperature gradient decreases from 100 mK/m to 30 mK/m at about 1100 m depth. The decreasing temperature gradient can be explained by assuming a convective heat transfer in the Buntsandstein/Muschelkalk aquifer.

The results of a production test show that there is only 1 inflow zone in borehole GPK 1 at 1812 m depth. 3 injection tests, using different injection flow rates, were conducted in borehole GPK 1. A total number of about 20 water accepting joints could be detected by temperature measurements. A second major outflow at 1728 m depth was encountered besides the 1 at 1812 m depth. About 47% of the injected water was lost at 1728 m depth and about 53% at 1812 m depth.

The high resolution temperature measurements showed definitely which joints are water accepting (partly dependent on pressure) and which are not.

The European Geothermal Project involved teams from France and Germany who collaborated to test a site in the Upper Rhine Valley for its suitability for terrestrial heat mining (hot dry rock (HDR) energy production). Some British scientists participated in specific tasks.
The site was chosen near Soulz-sous-Forets in Alsace at the location of the old oil field of Pechelbronn which was the first oil field field exploited in Europe since the 18th century.
It is situated on 1 of the summits of a very large thermic anomaly (200 km long and 20 km wide) where the mean geothermal gradient between the surface and 1500 m is known to be higher than 6.5 C/100 m. The programme began in July 1987 with a 2000 m deep borehole.

Below at 1375 m thick sediment cover, the granitic basement was penetrated to a depth of 2000 m. The temperature at the bottom of the hole was 140 C. The geothermal gradient within the sediments was unusually high (10 C per 100 m) and diminished to a normal after a series of fractures inside the Bundsandstein producing some water at 116 C with a total salinity 98 g/l. At the depth of 1820 m, hydraulically active natural fissure was reached. The artesian outflow from this zone was 0.15 l/s, with well head pressure of 1.6 bars. The thermal water produced from the well had a high chloride contents and clearly had an identical origin with the fluid collected from the Buntsandstein just above the granite. During the water injection tests, a second active natural fissure was detected normally closed out but which seemed to aquire a noticeable permeability at a well head pressure of about 40 bars.
THE WORK FORMS PART OF THE FRANCO-GERMAN COLLABORATIVE HDR PROJECT (SEE ALSO CONTRACT NOS.G0052D G0055D, G0080D, G0082D AND G0072F). THE MAIN EXPERIMENTAL WORK WILL OCCUR AT SOULTZ, BUT OPPORTUNITIES MAY ALSO BE TAKEN TO WORK AT OTHER RELEVANT SITES IN FRANCE OR GERMANY.
THE WORK WILL INVOLVE THERMAL TESTING DURING HYDRAULIC EXPERIMENTS TO DETERMINE:
- IN SITU THERMAL CONDITIONS IN THE BOREHOLES;
- HEAT EXCHANGE EXPERIMENTS DURING FLUID CIRCULATION;
- THE IDENTIFICATION OF FRACTURES BY MEANS OF THERMAL DISTURBANCES IN THE BOREHOLE.
THIS WORK WILL BE SUPPORTED BY MODEL CALCULATIONS, WORKING WITH TEAMS FROM UK (SEE CONTRACT NO.G0003UK) AND SWITZERLAND.

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Programa(s)

• FP1-ENNONUC 3C - Research and development programme (EEC) in the field of Non-Nuclear Energy, 1985-1988

Tema(s)

Datos no disponibles

Convocatoria de propuestas

Datos no disponibles

Régimen de financiación

CSC - Cost-sharing contracts

Coordinador

Niedersächsisches Landesamt für Bodenforschung

• Aportación de la UE: Sin datos
• Dirección: 30161 Hannover ; Alemania
• Coste total: Sin datos