Mission Statement

The Geothermal Energy & Geofluids group is endowed by the Werner Siemens Foundation and investigates reactive fluid (water, CO2, CxHy, N2) and (geothermal) energy (heat, pressure) transfer in the Earth’s crust employing computer simulations, laboratory experiments and field analyses to gain fundamental insights and to address a wide range of societal goals and concerns. ➞ Read More

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GEG News


31.10.2022

Doctoral Examination Isamu Naets

On October 28, 2022, Isamu Naets has successfully defended his PhD thesis, entitled: “A pore scale investigation of fluid flow heterogeneity and solute transport in rough-walled fractures”.


30.10.2022

Ending EGC2022 with great results and a new destination for EGC2025 in Zurich

The biggest geothermal event in Europe has ended. More than 1300 participants attended EGC2022. The next EGC2025 will be held in Zurich, from 6 to 10 October 2025, organized by Geothermie Schweiz and co-organized by ETH Zurich.


19.09.2022

Doctoral Examination Po-Wei Huang


On September 16th, 2022, Po-Wei Huang has successfully defended his PhD thesis, entitled: “Reactive transport modeling at the pore scale and upscaling to the Darcy scale”.



Videos

CO2-Plume Geothermal (CPG) power plants combine geologic CO2 storage with geothermal energy extraction.
© Shannon Gilley
macarthur_100mchange_video_link
Inexhaustible resource of clean, renewable Geothermal Energy.
© ETH Zurich

By 2050, geothermal energy can cover 25% of Switzerland’s heating needs in a CO2-neutral way. © Daniel Stegmann

Grimsel rock laboratory, safer drilling methods.
© 3sat nano

GEG Events

01.12.2022    09:15-10:00 (local time)
Exploring for georesources to power the energy transition - the geophysical perspective

Friedemann Samrock (invited talk)
BMD seminar series, Cologne, Germany


NEXT EVENT
06.12.2022    14:15-15:15
Determining the geothermal reinjection potential into sedimentary formations using datasets of hydrocarbon exploration"

Abel Marko (GEG group presentation)
GEG Meetings, ETH Zurich



24.01.2023    14:15-15:15
CMG software in the GEG group

Kevin Hau (GEG group presentation)
GEG Meetings, ETH Zurich


14.02.2023    14:15-15:15
Update from Turboden secondment

Tristan Merbecks (GEG group presentation)
GEG Meetings, ETH Zurich


21.02.2023    14:15-15:15
CO2-Plume Geothermal

Jasper de Reus (GEG group presentation)
GEG Meetings, ETH Zurich


02.05.2023    14:15-15:15
Coupled reservoir/wellbore simulations of multi-phase multi-component systems

Serhat Kucuk (GEG group presentation)
GEG Meetings, ETH Zurich


09.05.2023    14:15-15:15
AEGIS-CH: Status Update after first 10month.

Andreas Reinicke Reinicke (GEG group presentation)
GEG Meetings, ETH Zurich


16.05.2023    14:15-15:15
Project presentation: Non-Darcy to Darcy transition of natural convection in porous media.

Dario Schwendener (GEG group presentation)
GEG Meetings, ETH Zurich


23.05.2023    14:15-15:15
Update work progress

Luise Dambly (GEG group presentation)
GEG Meetings, ETH Zurich


06.06.2023    14:15-15:15
update numerical simulation 1

lily suherlina (GEG group presentation)
GEG Meetings, ETH Zurich



27.06.2023    14:15-15:15
Updates or final report

Batmagnai Erdenechimg (GEG group presentation)
GEG Meetings, ETH Zurich



Newest GEG Papers

Refereed journal papers accepted the last 6 months

Underlined names are links to current or past GEG members


The role of high-permeability inclusion on solute transport in a 3D-printed fractured porous medium: An LIF-PIV integrated study
Kong, X.-Z., M. Ahkami, I. Naets, and M.O. Saar, Transport in Porous Media, 2022. [Download PDF] [View Abstract]It is well-known that the presence of geometry heterogeneity in porous media enhances solute mass mixing due to fluid velocity heterogeneity. However, laboratory measurements are still sparse on characterization of the role of high-permeability inclusions on solute transport, in particularly concerning fractured porous media. In this study, the transport of solutes is quantified after a pulse-like injection of soluble fluorescent dye into a 3D-printed fractured porous medium with distinct high-permeability (H-k) inclusions. The solute concentration and the pore-scale fluid velocity are determined using laser-induced fluorescence and particle image velocimetry techniques. The migration of solute is delineated with its breakthrough curve (BC), temporal and spatial moments, and mixing metrics (including the scalar dissipation rate, the volumetric dilution index, and the flux-related dilution index) in different regions of the medium. With the same H-k inclusions, compared to a H-k matrix, the low-permeability (L-k) matrix displays a higher peak in its BC, less solute mass retention, a higher peak solute velocity, a smaller peak dispersion coefficient, a lower mixing rate, and a smaller pore volume being occupied by the solute. The flux-related dilution index clearly captures the striated solute plume tails following the streamlines along dead-end fractures and along the interface between the H-k and L-k matrices. We propose a normalization of the scalar dissipation rate and the volumetric dilution index with respect to the maximum regional total solute mass, which offers a generalized examination of solute mixing for an open region with a varying total solute mass. Our study presents insights into the interplay between the geometric features of the fractured porous medium and the solute transport behaviors at the pore scale. (Paper accepted 2022-07-07)
The Dynamic Evolution of the Lahendong Geothermal System in North-Sulawesi, Indonesia.
Suherlina, L, J Newson, Y Kamah, and M Brehme, Geothermics , 105, pp. 1-19, 2022. [Download PDF] [View Abstract]This study uses an integrated approach to characterize the dynamic evolution of the power- producing high-enthalpy geothermal system of Lahendong, North-Sulawesi, Indonesia. Lahendong has two primary reservoirs, the southern and the northern, which have been utilised for electricity production for more than twenty years. The main focus of this study is the characterisation of heat and mass flows in the system with respect to geological structures and permeability distribution. Also, it delineates how the geothermal system has evolved and the spatial variation of the response resulting from prolonged utilization of the reservoirs. This research implemented geological structure analysis on recent surface fault mapping and pre-existing fault studies from literature. Further, the study analysed well data comprising well pressure, enthalpy, drilling program reviews and tracer tests. Hydrochemical investigation compiled new and old surface and subsurface hydrochemical evolution in both the temporal and spatial domain. The results confirm several trends of faults in the study area: NE-SW and NW-SE are the major striking directions, while E-W and N-S are less dominant. The most apparent trends are NE- SW striking strike-slip faults, perpendicular NW-SE thrust faults and N-S and E-W striking normal faults. The faults compartmentalize the reservoir. A comparison of the southern and the northern reservoir shows that the south is more structurally controlled by faults; both reservoirs rely on fractures as permeability provider and are controlled by shallow hydrogeology, derived from the integrated analysis of transient well data. Geochemical analysis shows that the reservoir fluids have generally higher Electrical Conductivity and closer to fluid-rock equilibrium, probably due to boiling. Spring waters have generally become more acidic, which is an expected result of reservoir boiling and increased steam input to near-surface waters. The spatial distribution of changes shows permeability evolution over time and also the role of structural permeability in response to changing reservoir conditions. Observing and recording reservoir data is highly important to understand the reservoir response to production and ensure the long-term sustainability of the system. Additionally, the data is critical for making a major difference in the reservoir management strategy. (Paper accepted 2022-06-25)
Using CO2-Plume Geothermal (CPG) Energy Technologies to Support Wind and Solar Power in Renewable-Heavy Electricity Systems
van Brummen, A.C., B.M. Adams, R. Wu, J.D. Ogland-Hand, and M.O. Saar, Renewable and Sustainable Energy Transition, (in press). [Download PDF] [View Abstract]CO2-Plume Geothermal (CPG) technologies are geothermal power systems that use geologically stored CO2 as the subsurface heat extraction fluid to generate renewable energy. CPG technologies can support variable wind and solar energy technologies by providing dispatchable power, while Flexible CPG (CPG- F) facilities can provide dispatchable power, energy storage, or both simultaneously. We present the first study investigating how CPG power plants and CPG-F facilities may operate as part of a renewable- heavy electricity system by integrating plant-level power plant models with systems-level optimization models. We use North Dakota, USA as a case study to demonstrate the potential of CPG to expand the geothermal resource base to locations not typically considered for geothermal power. We find that optimal system capacity for a solar-wind-CPG model can be up to 20 times greater than peak- demand. CPG-F facilities can reduce this modeled system capacity to just over 2 times peak demand by providing energy storage over both seasonal and short-term timescales. The operational flexibility of CPG-F facilities is further leveraged to bypass the ambient air temperature constraint of CPG power plants by storing energy at critical temperatures. Across all scenarios, a tax on CO2 emissions, on the order of hundreds of dollars per tonne, is required to financially justify using renewable energy over natural-gas power plants. Our findings suggest that CPG and CPG-F technologies may play a valuable role in future renewable-heavy electricity systems, and we propose a few recommendations to further study its integration potential. (Paper accepted 2022-06-16)
Relating Darcy-scale chemical reaction order to pore-scale spatial heterogeneity
Huang, P.-W., B. Flemisch, C.-Z. Qin, M.O. Saar, and A. Ebigbo, Transport in Porous Media, 2022. [Download PDF] [View Abstract]Due to spatial scaling effects, there is a discrepancy in mineral dissolution rates measured at different spatial scales. Many reasons for this spatial scaling effect can be given. We investigate one such reason, i.e., how pore-scale spatial heterogeneity in porous media affects overall mineral dissolution rates. Using the bundle-of-tubes model as an analogy for porous media, we show that the Darcy-scale reaction order increases as the statistical similarity between the pore sizes and the effective-surface-area ratio of the porous sample decreases. The analytical results quantify mineral spatial heterogeneity using the Darcy-scale reaction order and give a mechanistic explanation to the usage of reaction order in Darcy-scale modeling. The relation is used as a constitutive relation of reactive transport at the Darcy scale. We test the constitutive relation by simulating flow-through experiments. The proposed constitutive relation is able to model the solute breakthrough curve of the simulations. Our results imply that we can infer mineral spatial heterogeneity of a porous media using measured solute concentration over time in a flow-through dissolution experiment. (Paper accepted 2022-06-08)