8. ágúst 2018

Workshop on Interpreting electrical resistivity in terms of hydrothermal activity: Advances and challenges

Workshop will be held at ÍSOR,Grensásvegur 9, 108 Reykjavik, Room Viðgelmir, August 27, 2018 at 9.00-16.00.

All are welcome but registration is needed.

The purpose of this workshop is to review and discuss what subsurface resistivity can tell about mineralogy and what mineralogy can tell about hydrothermal activity. The workshop focuses on two minerals, which are both witnesses of hydrothermal circulations and electrical conductors: smectite and pyrite. This workshop is the result of discussions in the frame of the PhD of Léa Lévy, a PhD student at the University of Iceland and Ecole Normale Supérieure (Paris) and organized by her PhD committee. It is a part of GEMex, a project funded by the European Union’s Horizon 2020 research and innovation programme under grant agreement No. 727550.


9:00–9:10 Opening address – Ólafur G. Flóvenz (ÍSOR)

9:10–10:50 Geothermal exploration today(electrical methods and mineral analysis)

9:10–9:30 On the importance of electrical conductivity in geothermal exploration- Gylfi Páll Hersir (ÍSOR)

      • The framework of interpreting resistivity models
      • Unknown parameters and limitations

9:30–9:50 Previous studies of electrical conductivity of rocks in Iceland- Ólafur G. Flóvenz (ÍSOR)

      • Influence of Cation Exchange Capacity and porosity
      • Effect of temperature

9:50–10:20 Hydrothermal alteration and resistivity models in high-temperature geothermal systems in NE-Iceland - Anette K. Mortensen (Landsvirkjun)

10:20–10:50 Deep feed zones in IDDP-2 well. Evidence from high temperature mineralogy - Guðmundur Ómar Friðleifsson (HS Orka)

10:50–11:05 Coffee

11:05–12:05 Natural elements affecting the resistivity of rocks – insight from laboratory work

11:05-11:35 Electrical properties of hydrothermal alteration at low temperature- Léa Lévy (University of Iceland and Ecole Normale Supérieure, France)

•  Influence of smectite quantity on electrical conductivity of volcanic rocks
Physical mechanism causing high electrical conduction in smectite
Discriminating smectite, pyrite and iron-oxides electrical responses

11:35-12:05 Electrical resistivity of high-temperature bodies in geothermal systems - Benoit Gilbert (University of Montpellier, France)

      • Resistivity of rhyolitic and basaltic melt up to 1200°C – Krafla
      • Resistivity of gabbro with epidote-chlorite alteration facies at 300-500°C – Reykjanes

12:05–12:45 Lunch

12:45-14:00 Clay minerals: What we can learn from their presence?

12:45-13:00 Clay minerals from the recently drilled well in Surtsey - Tobias B. Weisenberger (ÍSOR)

13:00-13:30 Clay minerals in geothermal systems: key markers of hydrodynamicsand thermal history - Patricia Patrier & Daniel Beaufort (University of Poitiers, France)

      • Clay minerals do not indicate crystallization temperature: examples of high-temperature smectite in active hydrothermal systems
      • Clay minerals provide valuable information about geothermal reservoir dynamics: active versus extinct hydrothermal system

13:30-14:00 Petrography and hydrothermal alteration of borehole KH6 in Krafla - David Escobedo (University of Montpellier, France)

14:00-15:00 Interest of sulphides for geothermal industry

14:00-14:30 Sulfur in hydrothermal systems - origin and transport - Barbara I. Kleine, Jan Prikryl, Jóhann Gunnarsson-Robin, Chiara Marieni, Snorri Guðbrandsson, Shuhei Ono, Martin Whitehouse, Robert Zierenberg, Kristján Jónasson, Sæmundur A. Halldórsson, Ingvi Gunnarsson, Andri Stefánsson  (University of Iceland)

14:30-15:00 Tracking the fate of re-injected CO2 and H2S in the Hellisheiði geothermal field- Bergur Sigfússson (Reykjavík Energy)

15:00-15:45 General discussion

15:45-16:00 Summary and conclusion - Freysteinn Sigmundsson (University of Iceland)