Abstract
The St1 Deep Heat Project with its two deep wells extending to 6.2-6.4 km depth was the world’s deepest industrial geothermal energy project carried out 2014-2022. The aim of this pilot was to build an EGS (enhanced geothermal system) heat exchanger at the depth of 5 - 6 km and to produce thermal power to a district heating network. Due to low hydraulic conductivity at the EGS reservoir depth, regardless of hydraulic stimulation, the project did not achieve its economic goal. Now there are two cased superdeep boreholes which provide an excellent opportunity to carry out multidisciplinary experiments at depths very rarely accessible. We review the Deep Heat Project and a recent geothermal-hydrogeological-microbial logging and sampling campaign. Equilibrium temperature logs and fluid samples to 5 km depth for hydrogeochemical, isotope geochemical and microbial analysis of water and gas were carried out successfully in September 2024.
Original language | English |
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Title of host publication | Lithospere 2024 |
Subtitle of host publication | Thirteenth Symposium on the Structure, Composition and Evolution of the Lithosphere |
Editors | Perttu Mikkola, Toni Veikkolainen, Suvi Heinonen, Hannu Koivula, Kaisa Nikkilä, Jochem Kamm, David Whipp, Riikka Kietäväinen, Hanna Silvennoinen |
Publisher | University of Helsinki |
Pages | 45-46 |
ISBN (Electronic) | 978-952-10-9614-3 |
Publication status | Published - 2024 |
MoE publication type | B3 Non-refereed article in conference proceedings |
Event | 13th Symposium on Structure, Composition and Evolution of the Lithosphere in Fennoscandia, LITO 2024 - GTK, Otaniemi, Espoo, Finland Duration: 12 Nov 2024 → 14 Nov 2024 https://www.seismo.helsinki.fi/ilp/lito2024/ |
Publication series
Series | University of Helsinki: Institute of Seismology report |
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Number | S-73 |
ISSN | 0357-3060 |
Conference
Conference | 13th Symposium on Structure, Composition and Evolution of the Lithosphere in Fennoscandia, LITO 2024 |
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Country/Territory | Finland |
City | Espoo |
Period | 12/11/24 → 14/11/24 |
Internet address |
Funding
DAFNE-22: Deep life, hydrogeology and geothermics in the ICDP-DAFNE scientific drilling project
Keywords
- geothermal
- temperature
- saline fluids
- microbiology
- crystalline rocks
- Precambrian