Dr.  Lars Yström

Dr. Lars Yström

  • Adenauerring 20b
    76131 Karlsruhe

Profile

Research topic:

The focus of our research is the processing and interpretation of hydrochemical data of geothermal fluid.
Mineral solubilities can be calculated from the chemical composition of a hot fluid. These saturation indices of dissolved mineral phases can be used to draw conclusions about the dissolution and precipitation reactions in the thermal water cycle. This is the base for estimating the potential of a thermal spring or a geothermal reservoir.

In addition, by using the initial chemistry of a geothermal fluid numerical modelling is created that determine the changes in fluid properties. This allows to calculate and evaluate geochemical processes within the reservoir and the power plant. This enables the optimal usage of the fluid and minimisation of uncontrolled outgassing or scaling.

Research activities

Geochemical exploration with solute geothermometry

In solute geothermometry, the hydrogeochemical composition of a geothermal fluid is used to predict the reservoir temperature in the subsurface.

Development and programming of the multicomponent geothermometer "MulT_predict"
"MulT_predict" is a numerically optimised geothermometer, wich calculates and optimises the saturation indices of multiple dissolved mineral phases in order to predict the reservoir temperature.

Development and programming of the artificial neural network geothermometer "AnnRG
"AnnRG" is a multi-layer perceptron, which has been trained with geochemical parameters and validated using in-situ measured reservoir temperatures.

Hydrogeochemical modelling

Based on PHREEQC, hyrdogeochemical reactions in geothermal fluids are modeled. Our focus is on the following topics:

  • Improvement of thermodynamic databases
  • Solubility reactions
  • Precipitation reactions
  • Degassing

Projects:

  • VESTA  (Very-High-Temperature Heat Aquifer Storage)

The "VESTA" project is investigating the utilisation of a former crude oil reservoir as a seasonal heat storage facility. As part of the project, we are investigating the release and mobilisation of residual crude oil by injecting hot fluids into the reservoir.

  • MALEG (Machine Learning for Enhancing Geothermal Energy Production)

The "MALEG" project is investigating how to increase the efficiency of geothermal power plants. For this purpose, power plant processes are quantified both physically, making experiments at a demonstrator (hardware twin), and deterministically, using hydrogeochemical modeling (digital twin). These results provide the database for an artificial intelligence that reflects the thermodynamic relationships within the power plant and shows potential for improvement.

Responsibilities: 

  • Project work
  • Supervision of student work
  • Teaching
  • IT officer

CV:

since 2024 Postdoc in Geothermal Energy and Reservoir Technology (KIT
2019 - 2023 PhD student at the Department of Civil Engineering, Geo and Environmental Sciences (KIT
2015 - 2018 M.Sc. Applied Geosciences (KIT)
2012 - 2015 B. Sc. Applied Geosciences (KIT)

Profile links:

Publications


2023
AnnRG - An artificial neural network solute geothermometer
Ystroem, L. H.; Vollmer, M.; Kohl, T.; Nitschke, F.
2023. Applied Computing and Geosciences, 20, Art.-Nr.: 100144. doi:10.1016/j.acags.2023.100144Full textFull text of the publication as PDF document
Deep learning and geochemical modelling as tools for solute geothermometry
Ystroem, L. H.; Vollmer, M.; Nitschke, F.; Kohl, T.
2023. European Geothermal Congress 2022. Proceedings, European Geothermal Energy Council (EGEC) Full textFull text of the publication as PDF document
Geochemical Constraints on the Operations of High Temperature Aquifer Energy Storage (HT-ATES) in Abandoned Oil Reservoirs
Nitschke, F.; Ystroem, L.; Bauer, F.; Kohl, T.
2023. 48th Workshop on Geothermal Reservoir Engineering, Standfort University

Conference contributions


2023
MALEG - Maschinelles Lernen zur Verbesserung der Geothermischen Energienutzung
Ystroem, L. H.; Trumpp, M.
2023, October 18. Der Geothermiekongress (DGK 2023), Essen, Germany, October 17–19, 2023 Full textFull text of the publication as PDF document
Geothermometer temperature predictions for DeepStor
Ystroem, L. H.; Nitschke, F.; Kohl, T.
2023, May 10. 10th Energy Center Annual Meeting (2023), Karlsruhe, Germany, May 10, 2023 Full textFull text of the publication as PDF document
Solute Geothermometry - Applications and Development
Ystroem, L. H.; Vollmer, M.; Nitschke, F.; Kohl, T.
2023, January 13. Webinar: "Focus on Geothermal (Webinar) : Energy for the Weekend" (2023), Online, January 13, 2023 Full textFull text of the publication as PDF document
2022
Deep learning and geochemical modelling as tools for solute geothermometry
Ystroem, L. H.; Vollmer, M.; Nitschke, F.; Kohl, T.
2022, October 19. European Geothermal Congress (EGC 2022), Berlin, Germany, October 17–21, 2022 Full textFull text of the publication as PDF document
2021
Reservoirtemperaturbestimmung mittels künstlicher neuronaler Netze (KNN)
Ystroem, L.; Vollmer, M.; Nitschke, F.; Kohl, T.
2021, November 30. Der Geothermiekongress (DGK 2021), Essen, Germany, November 30–December 2, 2021 Full textFull text of the publication as PDF document
An artificial neural network (ANN) as solute geothermometer
Ystroem, L.; Vollmer, M.; Nitschke, F.; Kohl, T.
2021, September 24. 9th European Geothermal Workshop (EGW 2021), Karlsruhe, Germany, September 23–24, 2021 Full textFull text of the publication as PDF document
An Integrated Sensitivity Analysis for Multicomponent Geothermometer for High Temperature Settings
Ystroem, L. H.; Nitschke, F.; Kohl, T.
2021, May 12. World Geothermal Congress (WGC 2021), Reykjavik, Iceland, May 21–26, 2021 Full textFull text of the publication as PDF document
Optimised multicomponent geothermometer MulT_predict
Ystroem, L. H.; Nitschke, F.; Kohl, T.
2021, February 15. 12th European Geothermal PhD Days (EGPD 2021), Paris, France, February 15–16, 2021 Full textFull text of the publication as PDF document
2020
Zeitliche und tiefenabhängige Effekte auf die Fluidchemie - Untersuchung granitischer Reservoire im Oberrheingraben mittels Multikomponentengeothermometrie
Ystroem, L. H.; Nitschke, F.; Held, S.; Kohl, T.
2020, November 11. Der digital Geothermiekongress (DGK 2020), Essen, Germany, November 9–13, 2020 Full textFull text of the publication as PDF document
MulT_predict - An optimised multicomponent geothermometer
Ystroem, L. H.; Nitschke, F.; Held, S.; Kohl, T.
2020, November 4. Student Technical Congress - German Section (STC 2020), Online, November 4–6, 2020 Full textFull text of the publication as PDF document
2019
MulT_predict - Entwicklung & Validierung eines Tools zur Reservoirtemperaturabschätzung basierend auf Multikomponentengeothermometrie
Ystroem, L. H.; Nitschke, F.; Held, S.; Kohl, T.
2019, November 21. Der Geothermiekongress (DGK 2019), Munich, Germany, November 19–21, 2019 Full textFull text of the publication as PDF document
MulT_predict - A Multicomponent Geothermometer optimized by Sensitivity Analysis
Ystroem, L. H.; Nitschke, F.; Held, S.; Kohl, T.
2019, October 9. 7th European Geothermal Workshop (EGW 2019), Karlsruhe, Germany, October 9–10, 2019 Full textFull text of the publication as PDF document
MulT_predict - A multicomponent geothermometer with integrated sensitivity analyses
Ystroem, L. H.; Nitschke, F.; Held, S.; Kohl, T.
2019, October 9. 7th European Geothermal Workshop (EGW 2019), Karlsruhe, Germany, October 9–10, 2019 Full textFull text of the publication as PDF document
MulT_predict - A multicomponent geothermometer for precise reservoir temperature estimation
Ystroem, L. H.; Nitschke, F.; Held, S.; Kohl, T.
2019, July 4. 8th Annual Conference of the KIT Energy Center (2019), Karlsruhe, Germany, July 4, 2019 Full textFull text of the publication as PDF document
2018
Validation of multicomponent geothermometer with sensitivity analysis in basaltic geothermal setting
Ystroem, L. H.; Nitschke, F.; Held, S.; Kohl, T.
2018, October 10. 6th European Geothermal Workshop (EGW 2018), Strasbourg, France, October 10–11, 2018 Full textFull text of the publication as PDF document