BGR Bundesanstalt für Geowissenschaften und Rohstoffe

Geothermal Well Horstberg Z1

Begin of project: July 1, 2003

End of project: December 31, 2018

Status of project: January 3, 2018

Einbohrlochzirkulation Horstberg Z1Einbohrlochzirkulation Horstberg Z1 Source: BGR

The Horstberg Z1 borehole is an abandoned gas exploration well in the North German Basin, located about 80 km north-east of Hannover. Since 2003 it has served as a research site for utilization and development of geothermal concepts in low permeability sedimentary rocks.

Of great importance was the hydraulic fracture operation carried out in 2003 at approx. 3800m depth in the Middle Buntsandstein. Approximately 20,000 m³ of fresh water without additives was injected into the Detfurth sandstone. Subsequent hydraulic tests showed that the induced hydraulic fracture has a very good hydraulic conductivity. Accordingly, two different concepts were tested: the cyclic method and the borehole circulation. In both cases, the artificially created crack serves as a drainage path for the thermal water and as a heat exchanger surface.

The good results of the scientific tests during the period between 2003 and 2009 at the Horstberg well formed the basis for the launch of the GeneSys demonstration project in Hanover.

The tests and investigations continue in Horstberg after renovation of the drilling site in 2016. The main goal of the current project is the comprehensive characterization of the induced hydraulic fracture. Different tests are provided for this purpose. Most important are long-term circulation tests with different flow rates and different pressure levels. The circulation is to take place over the induced hydraulic fracture between two formations of the Buntsandstein reservoir, the Detfurth sandstone and the Solling sandstone.

Horstberg Z1 – key data

  • Location: ~75 km NE of Hannover
  • Target formation: Middle Buntsandstein
  • Depth: ~3,800 m
  • Temperature: ~145 °C in target formation



The research and development project on the borehole of Horstberg was funded by the Federal Ministry for the Environment, Nature Conservation and Nuclear Safety (BMU) under Grant No. 0327116 (1.10.2002 - 31.12.2005) and 0329996 (1.4.2005 - 30.6.2009). The Federal Ministry of Economics and Energy (BMWi) provides the current funding under Grant No. 0325946.


Project contributions:


Jung, R., Orzol, J., Tischner, T., Jatho, R., Kehrer, P. (2005): The geothermal project GeneSys – Results of massive waterfrac-tests in the Bunter sandstone formation in the Northern German Basin. In: Proceedings, 30th Workshop on Geothermal Reservoir Engineering, 31.01. – 02.02.05, Stanford, USA.

Jung, R., Orzol, J., Kehrer, P. Jatho, R. (2005): Verbundprojekt: GeneSys, Vorstudie – Erprobung der Wasserfractechnik und des Einsonden-Zweischichtverfahrens für die Direktwärmenutzung aus gering permeablen Sedimentgesteinen. Abschlussbericht.

Wessling, S., Junker, R., Rutqvist, J., Silin, D., Sulzbacher, H., Tischner, T. & Tsang, Chin-Fu (2009): Pressure analysis of the hydromechanical fracture behaviour in stimulated tight sedimentary geothermal reservoirs, Geothermics, 38, (2009), 211-226.

Hesshaus, A., Hauswirth, H., Jatho, R., Tischner, T., Junker, R., Schellschmidt, R. & Sulzbacher, H. (2010): GeneSys Horstberg II – Methoden und Konzepte zur Erdwärmegewinnung aus gering permeablen Sedimentgesteinen. Abschlussbericht zum BMU-Vorhaben 032996, BGR-Bericht, 137p.

Gerling, J.P., Tischner, T., Kosinowski, M., Bräuer, V. (2015): Erdwärmegewinnung mittels generierter geothermischer Systeme (GeneSys). Geologisches Jahrbuch, Reihe A, Heft 162.

Contact 1:

Dr. Torsten Tischner
Phone: +49-(0)511-643-2475
Fax: +49-(0)511-643-2304

Contact 2:

Dr. Wolfram Rühaak
Phone: +49-(0)511-643-2032

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