The first GEG Group Relay Running Team. SOLA on May 4, 2019
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.
GEG News
New photo gallery of geothermal exploration for green energy in Mongolia. Friedemann Samrock
03.02.2020
The burning of coal for heating is a major cause of harmful air pollution and massive greenhouse gas emissions in Mongolia’s cities. This photo gallery provides authentic insights into the progress of introducing a scientific framework for geothermal exploration.
read more
Doctoral Examination Edoardo Rossi
08.01.2020
On Tuesday, January 7th, Edoardo Rossi has successfully passed the Doctoral Examination. Edoardo’s PhD thesis title: “Combined Thermo-Mechanical Drilling technology to enhance access to deep geo-resources”.
Prix d’Excellence by the Enovo Foundation
01.12.2019
Marthe Faber has been awarded the ‘Prix d’Excelence’ by the Enovo Fondation and its partners, the Association da Vinci and l’ANEIL (National Association of Luxembourg Engineering Students). The prize is awarded to students with the best thesis grade in engineering. Marthe conducted the research for her MSc thesis ‘Usage Of Inter-Site Electromagnetic Transfer Functions In Exploration For Geothermal Resources’ at GEG in 2018.
read more – link to the Foundation de Luxembourg
read more – link to the Foundation de Luxembourg
Marthe Faber
Top Ranking for ETH Zurich’s Earth Sciences in Nature Index 2018
20.12.2018
ETH is listed number one among the 200 best academic institutions in Earth & Environmental Sciences in the Nature Index 2018. This index is based on publications in the 82 journals selected as the most important journals by two panels of scientists, which are independent of the Nature Publishing Group.
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SNF Ambizione Grant
25.10.2018
Dr. Allan Leal has been awarded an SNF Ambizione grant to develop innovative computational methods for ultra-fast simulations of coupled physical and chemical processes using machine learning and GPU parallel computing, starting on January 1, 2019.
Link to personal homepage of Allan Leal
Link to personal homepage of Allan Leal
SNF R4D Grant
01.10.2018
Dr. Friedemann Samrock has been awarded an SNF R4D grant to develop a geoscientific framework for geothermal exploration and energy utilization in Mongolia, started on September 1, 2018.
Link to Project’s page of SNF
Link to Project’s page of SNF
Inauguration of commemorative plaque for the Werner Siemens Foundation
12.09.2017
© Felix Wey
Werner Siemens Foundation visits the Geothermal Energy & Geofluids Group and has a guided tour at the GEG Laboratories.
read more on ETH Foundation webpage
read more on News of GEG webpage
GEG Videos
Inexhaustible resource of clean, renewable Geothermal Energy.
© ETH Zurich
Grimsel rock lab, feasibility of geothermal power plants.
© ETH Zurich
Grimsel rock laboratory, safer drilling methods.
© 3sat nano
© 2018 ETH Zurich
GEG Events
NEXT EVENT
03.03.2020
Recent progress on the geologic and in situ stress characterization of the Bedretto Underground LaboratoryXiadong Ma (GEG group presentation)
GEG Meetings, ETH Zurich read more
27.04.2020
How the Spatial Continuity of Permeability Affects Hydrothermal Convection: A Study Using Entropy ProductionJan Niederau (contributed talk)
World Geothermal Congress 2020, Reykjavik, Iceland read more
27.04.2020
Using sequestered CO2 as geothermal working fluid to generate electricity and store energy.Benjamin Adams (contributed talk)
WGC 2020, Reykjavik, Iceland read more
27.04.2020
Combining direct air capture and geothermal heat and electricity generation for net-negative carbon dioxide emissionsBenjamin Adams (contributed talk)
WGC 2020, Reykjavik, Iceland read more
28.04.2020
Characterization of Subsurface Heat-Transport Processes in the Canton of Aargau Using an Integrative WorkflowJan Niederau (poster presentation)
World Geothermal Congress 2020, Reykjavik, Iceland read more
29.04.2020
Estimation of Effective Surface Area: A Study on Dolomite Cement Dissolution in SandstonesJin Ma (talk)
World Geothermal Congress (WGC) 2020, Reykjavik, Iceland read more
29.04.2020
Investigating Different Formulations for Hydrothermal Convection in Geothermal SystemsJan Niederau (poster presentation)
WGC2020, Reykjavik, Iceland read more
29.04.2020
Coupling Dynamic Heat Demands of Buildings with Borehole Heat Exchanger Simulations for Realistic Monitoring and ForecastJan Niederau (poster presentation)
World Geothermal Congress 2020, Reykjavik, Iceland read more
30.04.2020
A Numerical Model for Formation Dry-out During CO2 Injection in Fractured Reservoirs Using the MOOSE Framework: Implications for CO2-based Geothermal Energy ExtractionPhilipp Schädle (contributed talk)
World Geothermal Congress 2020, Reykjavík, Iceland read more
24.05.2020
Laser-Induced Fluorescence (LIF) study of solute transport in 3D-printed fractured porous mediaMehrdad Ahkami (contributed talk)
InterPore 2020, Qingdao read more
GEG Open Positions
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GEG Paper Alerts
Characterization of the effects of hydraulic stimulation with tracer-based temporal moment analysis and tomographic inversion
Kittilä, A., M.R. Jalali, M. Somogyvári, K.F. Evans, M.O. Saar, and X.-Z. Kong Geothermics, (in press). [View Abstract]Tracer tests were conducted as part of decameter-scale in-situ hydraulic stimulation experiments at the Grimsel Test Site to investigate the hydraulic properties of a stimulated crystalline rock volume and to study the stimulation-induced hydrodynamic changes. Temporal moment analysis yielded an increase in tracer swept pore volume with prominent flow channeling. Post-stimulation tomographic inversion of the hydraulic conductivity, K, distribution indicated an increase in the geometric mean of logK and a decrease in the Dykstra-Parsons heterogeneity index. These results indicate that new flow path connections were created by the stimulation programs, enabling the tracers to sweep larger volumes, while accessing flow paths with larger hydraulic conductivities. Simulating Electropulse Fracture of Granitic Rock
Walsh, S.D.C., and D. Vogler International Journal of Rock Mechanics and Mining Sciences, 128, pp. 104238, 2020. [Download PDF] [View Abstract]Electropulse treatments employ a series of high-voltage discharges to break rock into small fragments. As these methods are particularly suited to fracturing hard brittle rocks, electropulse treatments can serve to enhance or substitute for more traditional mechanical approaches to drilling and processing of these materials. Nevertheless, while these treatments have the potential to improve hard-rock operations, the coupled electro-mechanical processes responsible for damaging the rock are poorly described. The lack of accurate models for these processes increases the difficulty of designing, controlling and optimizing tools that employ electropulse treatments and limits their range of application.
This paper describes a new modeling method for studying electropulse treatments in geotechnical operations. The multiphysics model simulates the passage of the pulse, electrical breakdown in the rock, and the mechanical response at the grain-scale. It also accounts for the contributions from different minerals and porosities, allowing the effect of material composition to be considered. In so doing, it provides a means to investigate the different physical and operational factors influencing electropulse treatments. Simulation of rock failure modes in thermal spallation drilling
Vogler, D., S.D.C. Walsh, P. Rudolf von Rohr, and M.O. Saar Acta Geotechnica, pp. 1-14, 2020. [Download PDF] [View Abstract]Thermal spallation drilling is a contact-less means of borehole excavation that works by exposing a rock surface to a high-temperature jet flame. In this study, we investigate crucial factors for the success of such thermal drilling operations using numerical simulations of the thermomechanical processes leading to rock failure at the borehole surface. To that end, we integrate a model developed for spalling failure with our thermomechanical simulations. In particular, we consider the role of material heterogeneities, maximum jet-flame temperature and maximum jet-flame temperature rise time on the onset of inelastic deformation and subsequent damage. We further investigate differences in energy consumption for the studied system configurations. The simulations highlight the importance of material composition, as thermal spallation is favored in fine-grained material with strong material heterogeneity. The model is used to test the relationship between the jet-flame temperature and the onset of thermal spallation. A Numerical Investigation into Key Factors Controlling Hard Rock Excavation via Electropulse Stimulation
Vogler, D., S.D.C. Walsh, and M.O. Saar Journal of Rock Mechanics and Geotechnical Engineering, (in press). [View Abstract]Electropulse stimulation provides an energy-efficient means of excavating hard rocks through repeated application of high voltage pulses to the rock surface. As such, it has the potential to confer significant advantages to mining and drilling operations for mineral and energy resources. Nevertheless, before these benefits can be realized, a better understanding of these processes is required to improve their deployment in the field.
In this paper, we employ a recently developed model of the grain-scale processes involved in electropulse stimulation to examine excavation of hard rock under realistic operating conditions. To that end, we investigate the maximum applied voltage within ranges of 120~kV to 600~kV, to observe the onset of rock fragmentation. We further study the effect of grain size on rock breakage, by comparing fine and coarse grained rocks modeled after granodiorite and granite, respectively. Lastly, the pore fluid salinity is investigated, since the electric conductivity of the pore fluid is shown to be a governing factor for the electrical conductivity of the system. This study demonstrates that all investigated factors are crucial to the efficiency of rock fragmentation by electropulsing.
Field test of a Combined Thermo-Mechanical Drilling technology. Mode I: Thermal spallation drilling
Rossi, E., S. Jamali, M.O. Saar, and Ph. Rudolf von Rohr Journal of Petroleum Science and Engineering, 107005, 2020. [Download PDF] A lattice-Boltzmann study of permeability-porosity relationships and mineral precipitation patterns in fractured porous media
Ahkami, M., A. Parmigiani, P.R. Di Palma, M.O. Saar, and X.-Z. Kong Computational Geosciences, 2020. [Download PDF] [View Abstract]Mineral precipitation can drastically alter a reservoir’s ability to transmit mass and energy during various engineering/natural subsurface processes, such as geothermal energy extraction and geological carbon dioxide sequestration. However, it is still challenging to explain the relationships among permeability, porosity, and precipitation patterns in reservoirs, particularly in fracture-dominated reservoirs. Here, we investigate the pore-scale behavior of single-species mineral precipitation reactions in a fractured porous medium, using a phase field lattice-Boltzmann method. Parallel to the main flow direction, the medium is divided into two halves, one with a low-permeability matrix and one with a high-permeability matrix. Each matrix contains one flow-through and one dead-end fracture. A wide range of species diffusivity and reaction rates is explored to cover regimes from advection- to diffusion-dominated, and from transport- to reaction-limited. By employing the ratio of the Damköhler (Da) and the Peclet (Pe) number, four distinct precipitation patterns can be identified, namely (1) no precipitation (Da/Pe < 1), (2) near-inlet clogging (Da/Pe > 100), (3) fracture isolation (1 < Da/Pe < 100 and Pe > 1), and (4) diffusive precipitation (1 < Da/Pe < 100 and Pe < 0.1). Using moment analyses, we discuss in detail the development of the species (i.e., reactant) concentration and mineral precipitation fields for various species transport regimes. Finally, we establish a general relationship among mineral precipitation pattern, porosity, and permeability. Our study provides insights into the feedback loop of fluid flow, species transport, mineral precipitation, pore space geometry changes, and permeability in fractured porous media. Field test of a Combined Thermo-Mechanical Drilling technology. Mode II: Flame-assisted rotary drilling
Rossi, E., S. Jamali, D. Schwarz, M.O. Saar, and Ph. Rudolf von Rohr Journal of Petroleum Science and Engineering, 2020. [Download PDF] Modelling of hydro-mechanical processes in heterogeneous fracture intersections using a fictitious domain method with variational transfer operators
von Planta, C., D. Vogler, X. Chen, M.G.C. Nestola, M.O. Saar, and R. Krause Computational Geosciences, 2020. [View Abstract]Fluid flow in rough fractures and the coupling with the mechanical behavior of the
fractures pose great difficulties for numerical modeling approaches, due to complex
fracture surface topographies, the non-linearity of hydromechanical processes and
their tightly coupled nature. To this end, we have adapted a fictitious domain method to
enable the simulation of hydromechanical processes in fracture-intersections. The
main characteristic of the method is the immersion of the fracture domain, modelled as
a linear elastic solid, in the surrounding fluid, modelled with the incompressible Navier
Stokes equations. The fluid and the solid problems are coupled with variational transfer
operators. Variational transfer operators are also used to solve contact within the
fracture using a mortar approach and to generate problem specific fluid grids. With
respect to our applications, the key features of the method are the usage of different
finite element discretizations for the solid and the fluid problem and the automatically
generated representation of the fluid-solid boundary.
We demonstrate that the presented methodology resolves small-scale roughness on
the fracture surface, while capturing fluid flow field changes during mechanical loading.
Starting with 2D/3D benchmark simulations of intersected fractures, we end with an
intersected fracture composed of complex fracture surface topographies, which are in
contact under increasing loads. The contributions of this article are: (1) the application
of the fictitious domain method to study flow in fractures with intersections, (2) a
mortar based contact solver for the solid problem, (3) generation of problem specific
grids using the geometry information from the variational transfer operators. A combined thermo-mechanical drilling technology for deep geothermal and hard rock reservoirs
Rossi, E., S. Jamali, V. Wittig, M.O. Saar, and Ph. Rudolf von Rohr Geothermics, 85, pp. 1-11, 2020. [Download PDF] Comparative study of Basel EGS reservoir faults inferred from analysis of microseismic cluster datasets with fracture zones obtained from well log analysis
Ziegler, M., and K.F. Evans Journal of Structural Geology, 130, 2020.