Article
Geochemistry & Geophysics
Paul Wersin, Martin Mazurek, Thomas Gimmi
Summary: This study evaluates the porewater chemistry data obtained from different extraction methods in clayrocks and finds that the composition of porewater varies and is constrained by diffusive exchange, carbonate mineral and celestite equilibria.
APPLIED GEOCHEMISTRY
(2022)
Article
Geochemistry & Geophysics
Shingo Yokoyama, Misato Shimbashi, Daisuke Minato, Yasutaka Watanabe, Andreas Jenni, Urs Mader
Summary: The experiment revealed that the interaction between cement and bentonite can lead to various degrees of mineralogical changes, but over a 10-year period, detectable changes in the mineralogical nature of montmorillonite did not occur.
Article
Chemistry, Physical
Julio Goncalves, Jean-Michel Matray, Catherine Ji Yu
Summary: The relevant transport processes in clay media for deep geological disposal of radioactive waste, including the debated overpressures, were investigated in the Deep Borehole experiment at the Mont Terri URL. An anomalous pressure of about 13 bars was identified, and a multi-packer hydraulic system was used to determine the driving forces and transport coefficients. 1D transport models with osmotic processes were developed to reproduce the measured pressure and salinity profiles, showing the dominance of diffusion over advection at Mont Terri.
APPLIED CLAY SCIENCE
(2023)
Article
Environmental Sciences
Tilo Kneuker, Markus Furche
Summary: Opalinus Clay is a potential host rock for radioactive waste disposal, with varying lithological and structural variability captured through a multidisciplinary approach. Shaly facies types are found to be more homogenous, while sandy and carbonate-rich sandy facies represent the more heterogeneous lithofacies types. The varying resistivity is attributed to differences in clay mineral and carbonate content, with brittle faults observed throughout the investigated section.
ENVIRONMENTAL EARTH SCIENCES
(2021)
Article
Geosciences, Multidisciplinary
Nico Graebling, Ozgur Ozan Sen, Lars Bilke, Tuanny Cajuhi, Dmitri Naumov, Wenqing Wang, Gesa Ziefle, David Jaeggi, Jobst Massmann, Gerik Scheuermann, Olaf Kolditz, Karsten Rink
Summary: Underground Research Laboratories (URLs) allow large-scale geoscientific in-situ experiments. At Mont Terri URL in Switzerland, international research groups conduct numerous experiments, but the data obtained is often restricted to the researchers involved in the specific experiment.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Thermodynamics
Guang Hu, Martin Schoenball, Wilfried Pfingsten
Summary: Machine learning-assisted modelling can improve the safe operation of deep geological repositories (DGR). In this study, a ML-assisted 3D heat transport model for a mock-up DGR tunnel was developed and validated with experimental data. The results demonstrate the effectiveness of ML in predicting temperature evolution and identifying faulty sensor data. Rating: 9/10
INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER
(2023)
Article
Energy & Fuels
G. Ziefle, T. Cajuhi, N. Graebling, D. Jaeggi, O. Kolditz, H. Kunz, J. Massmann, K. Rink
Summary: To enable safe geological storage of high-level radioactive waste, it is important to have a comprehensive understanding of the physical processes, geological conditions, and geotechnical factors involved. The CD-A experiment conducted in the Mont Terri Rock Laboratory in Switzerland, along with extensive investigations, provides a multidisciplinary interpretation and numerical modeling of the hydraulic and mechanical processes in claystone under different climatic conditions.
GEOMECHANICS FOR ENERGY AND THE ENVIRONMENT
(2022)
Article
Chemistry, Physical
Tilo Kneuker, Reiner Dohrmann, Kristian Ufer, David Jaeggi
Summary: The research focused on the mineralogical and geochemical analysis of Opalinus Clay samples from Switzerland. It analyzed the degree of ordering of clay minerals and their impact on sorption and swelling properties. The study identified five main facies and emphasized the importance of combining lithofacial studies with mineralogical investigations.
APPLIED CLAY SCIENCE
(2023)
Article
Engineering, Geological
Yara Barakat, Yu-Jun Cui, Nadia Mokni, Pierre Delage, Frederic Bernier
Summary: This study investigates the dissolution of quartz and calcite minerals in Opalinus Clay under different pH conditions. The results show that quartz dissolution occurs significantly at pH higher than 11.5, while calcite dissolution occurs at pH higher than 8.5. The dissolution of quartz is mainly influenced by exposure time, while the dissolution of calcite depends on both exposure time and pH value.
ENGINEERING GEOLOGY
(2022)
Article
Energy & Fuels
Dario Sciandra, Iman Rahimzadeh Kivi, Victor Vilarrasa, Roman Y. Makhnenko, Dorothee Rebscher
Summary: Ensuring the sealing capacity of caprocks is crucial as CO2 storage expands. Laboratory experiments with intact rock samples have shown that low-permeability and high-entry pressure caprocks have excellent sealing capacities. However, discontinuities such as bedding planes, fractures, and faults affect rock properties at the field scale and are challenging to monitor in industrial-scale applications. Underground Research Laboratories (URLs) provide an ideal setting to investigate the field-scale sealing capacity of caprocks, allowing for well-controlled experiments. The CO2 Long-term Periodic Injection Experiment (CO2LPIE) at the Mont Terri rock laboratory aims to study the advance of CO2 in Opalinus Clay, a clay-rich rock with bedding planes dipping at 45 degrees. By conducting hydro-mechanical simulations, researchers were able to predict the system response and design the experiment accordingly.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2022)
Article
Geochemistry & Geophysics
Louis De Barros, Yves Guglielmi, Frederic Cappa, Christophe Nussbaum, Jens Birkholzer
Summary: Fault slip induced by fluid perturbation in shale formations can impact the integrity of shale caprocks for reservoirs holding buoyant fluids, and a better understanding of these processes is critical for reservoir monitoring. In this study, seismic responses of a shale fault exposed to fluid pressurization during an injection experiment were analyzed. Two types of seismic signals were observed: tremors associated with fluid-induced slip propagation, and micro-earthquakes triggered by stress perturbations. Tremors serve as a more direct observation for fluid-induced slip, providing a useful tool for monitoring fluid leakage and sealing integrity.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Tanner A. Shadoan, Jonathan B. Ajo-Franklin, Yves Guglielmi, Todd Wood, Michelle Robertson, Paul Cook, Florian Soom, Thomas M. Daley, Chet Hopp, Veronica Rodriguez Tribaldos, Pierpaolo Marchesini, Christophe Nussbaum, Jens Birkholzer
Summary: This study conducted a time-lapse seismic experiment to monitor a reactivated fault within the Opalinus clay formation at the Mont Terri Rock Laboratory. The measured changes in P-wave velocity were related to the opening of the fault damage zone, providing insights into changes in permeability within the fault zone. This research is important for predicting, detecting, and preventing CO2 movement.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geochemistry & Geophysics
Sina Hale, Xavier Ries, David Jaeggi, Philipp Blum
Summary: In this study, a hydromechanical characterization of an evolving excavation damaged zone (EDZ) in the Mont Terri underground rock laboratory in Switzerland was conducted using three different handheld devices. The study found permeable fractures with specific hydraulic apertures, observed cyclic long-term fracture aperture oscillations, and determined the uniaxial compressive strength of the rock. The study's methodological approach is suitable for time-dependent monitoring of EDZs, providing spatially resolved investigation of hydraulic and mechanical fracture apertures, surface roughness, and rock parameters.
Review
Engineering, Geological
Yara Barakat, Nadia Mokni, Yu-Jun Cui, Pierre Delage, Frederic Bernier
Summary: Three small-scale mock-up tests were conducted on Opalinus Clay samples to investigate the self-sealing behavior of fractures. The tests showed that synthetic water and alkaline solution may hinder the self-sealing process, while saline solutions can increase permeability and accelerate hydration but cannot completely seal the fractures.
CANADIAN GEOTECHNICAL JOURNAL
(2023)
Article
Chemistry, Physical
Ji-Won Kim, Song-Hun Chong, Gye-Chun Cho
Summary: This study investigates the effects of gouge material and thickness on wave propagation in equivalent continuum jointed rocks through experimental methods. The results show that gouge fill leads to changes in wave velocity and increased gouge thickness causes a significant stiffness contribution of the gouge material properties to the overall stiffness.