Research application of the St1 superdeep boreholes in Espoo, southern Finland

Ilmo Kukkonen*, Riikka Kietäväinen, Ville Nenonen, Malin Bomberg, Hanna Miettinen, Mari Nyyssönen, Maija Nuppunen-Puputti, Aino Karjalainen, Jussi Rytkönen

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientific

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 languageEnglish
Title of host publicationLithospere 2024
Subtitle of host publicationThirteenth Symposium on the Structure, Composition and Evolution of the Lithosphere
EditorsPerttu Mikkola, Toni Veikkolainen, Suvi Heinonen, Hannu Koivula, Kaisa Nikkilä, Jochem Kamm, David Whipp, Riikka Kietäväinen, Hanna Silvennoinen
PublisherUniversity of Helsinki
Pages45-46
ISBN (Electronic)978-952-10-9614-3
Publication statusPublished - 2024
MoE publication typeB3 Non-refereed article in conference proceedings
Event13th Symposium on Structure, Composition and Evolution of the Lithosphere in Fennoscandia, LITO 2024 - GTK, Otaniemi, Espoo, Finland
Duration: 12 Nov 202414 Nov 2024
https://www.seismo.helsinki.fi/ilp/lito2024/

Publication series

SeriesUniversity of Helsinki: Institute of Seismology report
NumberS-73
ISSN0357-3060

Conference

Conference13th Symposium on Structure, Composition and Evolution of the Lithosphere in Fennoscandia, LITO 2024
Country/TerritoryFinland
CityEspoo
Period12/11/2414/11/24
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

Fingerprint

Dive into the research topics of 'Research application of the St1 superdeep boreholes in Espoo, southern Finland'. Together they form a unique fingerprint.

Cite this