Highlights

• Distributed acoustic sensing along a 3.6 km downhole cable
• Water injection monitoring and reservoir characterization

We had the thrilling opportunity to contribute to the well completion and production testing of two newly drilled geothermal wells at the geothermal site Schäftlarnstraße, in the southern part of the city center of Munich. Two fiber-optic cables were installed in the wells, one permanently cemented behind the anchor casing and one suspended in the well using a rod construction. We monitored and analyzed distributed acoustic data during the cementing phase and during a well injection testing phase.

Funding

The fiber-optic cable was installed in the framework of the Geothermal Alliance Bavaria project, funded by the Bavarian Ministry of Economic Affairs, Energy and Technology. SWM Services GmbH was significantly involved with planning and installation services, providing the wellsite, the borehole and taking the risks of the cable installation. A part of this work was financed by the GeConnect project (Geothermal Casing Connections for Axial Stress Mitigation), coordinated by ÍSOR, which is funded through the ERANET cofund GEOTHERMICA (Project no. 731117), from the European Commission, Technology Development Fund (Iceland), Bundesministerium für Wirtschaft und Energie aufgrund eines Beschlusses des Deutschen Bundestages (Germany) and Ministerie van Economische Zaken (The Netherlands).

References

Lipus, M. P., Schöderle, F., Reinsch, T., Wollin, C., Krawczyk, C., Pfrang, D., Zosseder, K. (2021): Dynamic motion monitoring of a 3.6 km long steel rod in a borehole during cold-water injection with distributed fiber-optic sensing. - Solid Earth. (open access link)

Schölderle, F., Lipus, M. P., Pfrang, D., Reinsch, T., Haberer, S., Einsiedl, F., Zosseder, K. (2021): Monitoring cold water injections for reservoir characterization using a permanent fiber optic installation in a geothermal production well in the Southern German Molasse Basin. - Geothermal Energy, 9, 21. (open access link)