52 Works

Impacts of probabilistic geological realizations in a geothermal reservoir using numerical and statistical investigations

Ali Dashti , Maziar Gholami Korzani , Christophe Geuzaine & Thomas Kohl
Achieving a (?) reliable geological model is the foremost step in all underground resource assessments. However, regarding the sparsity of data and lack of knowledge, a spectrum of solutions makes more sense compared to a single deterministic model. It this study, a probabilistic geological modeler (Gempy) is used to understand the effect of existing uncertainty in the data representing subsurface layers and faults. A synthetic single fault model in which both the layers and fault...

Reservoir characterization of the coal-bearing Upper Carboniferous clastic succession, Ruhr area, Germany

Jonas Greve , Benjamin Busch , Dennis Quandt & Christoph Hilgers
Structural Geology & Tectonics, Karlsruhe Institute of Technology(2);Due to the closure of coal mining in the northwestern German coalfields, active mine water drainage becomes technically redundant. As a result, the rising mine water table affects the subsurface stress conditions and may induce heterogeneous ground movements of fault blocks. Petrophysical properties of the Upper Carboniferous (Westphalian A and B) rocks are crucial to understand subsurface behavior during mine water rise. As a part of the interdisciplinary...

Regional deformation imprints from anisotropy of magnetic susceptibility data – an example from the Raichur Schist Belt (Dharwar Craton, India)

Santu Biswas, Manish A Mamtani , Agnes Kontny & Christoph Hilgers
The Raichur Schist Belt (RSB) is a NW-SE trending late-Archaean greenstone belt that forms part of the supracrustal units lying over an older gneissic basement. Granites (ca 2.5 Ga) occur in the vicinity of the RSB. The metavolcanics and granites are both massive and lack a field foliation and/or lineation. To work out the time-relationship between emplacement, fabric development and regional deformation of the granite vis-à-vis metavolcanic rocks and regional deformation, we performed Anisotropy of...

Self-potential and electromagnetic radiation monitoring of hydraulic fracturing experiments at the Äspö hard rock laboratory (Sweden)

Nadine Haaf & Eva Schill
At the Äspö hard rock underground laboratory in Sweden, six in situ hydraulic fracturing experiments took place at 410 m depth. A multistage hydraulic fracturing approach is tested with a low environmental impact, e.g., induced seismicity. The idea is to mitigate induced seismicity and preserve the permeability enhancement process under safe conditions. The fractures are initiated by two different injection systems (conventional and progressive). An extensive sensor array is installed at level 410 m, including...

Characterization of pore space in sandstone using the anisotropy of magnetic susceptibility

Julius Schenk , Agnes Kontny , Benjamin Busch , Ilner Khasanov & Hagen Steger
The pore space in siliciclastic rocks is one of the most important petrophysical properties in reservoir rock characterization. Of particular interest is the 3D distribution of pore space and permeability for the purpose of reservoir model development. We used a magnetic technique to determine the preferred orientation of the pore space. The approach is based on the injection of a magnetic ferrofluid, which is a stable colloidal suspension of approx. 10 nm-sized magnetite particles, into...

Numerical Modeling of the 2007-2009 Lava Dome Growth in the Crater of Volcán de Colima, México

Natalya Zeinalova & Alik Ismail-Zadeh
Volcán de Colima is active andesitic stratovolcano in México located at the height of about 3860 m above sea level. It belongs to the Colima Volcanic complex within the Trans-Mexican Volcanic Belt. This volcano is characterized by intermittency of explosive and effusive episodes of volcanic eruptions. For 2007-2009 slowly extruded magma led to a lava dome formation and growth in the volcanic crater. In this work, we present two-dimensional numerical models of the lava dome...

Performance of manganese oxide sorbents for direct lithium extraction from geothermal brines

Klemens Slunitschek , Jochen Kolb & Elisabeth Eiche
Lithium is one of the critical elements for the realization of electric mobility and energy transition. With a contribution to global Li-production and recycling of less than 1% (2017), Europe depends almost entirely on Li-import. To reduce the dependency, new and unconventional Li resources are explored in the EU. One resource are highly saline brines from geothermal reservoirs of the Upper Rhine Graben (URG), characterized by Li concentrations of up to 200 mg/L. Due to...

On-site hydraulic and mechanical characterization of a claystone around a non-lined test tunnel in Mont Terri, Switzerland

Sina Hale , Xavier Ries , David Jaeggi & Philipp Blum
The rock mass around man-made underground structures inevitably experiences major changes in hydraulic and mechanical properties, commonly referred to as excavation damage. In host rock formations for underground nuclear waste storage, such an excavation damaged zone (EDZ) is potentially critical and therefore requires reliable field data sets for safety assessment and the estimation of the long-term behavior. In this study, different on-site measurements were carried out in the EZ-B niche of the Mont Terri Rock...

SpannEnD - The crustal stress state of Germany

Steffen Ahlers , Andreas Henk , Tobias Hergert , Karsten Reiter , Birgit Müller , Luisa Röckel , Oliver Heidbach , Sophia Morawietz , Magdalena Scheck-Wenderoth & Denis Anikiev
Information about the recent stress state of the upper crust is important for understanding tectonic processes and for the use of the underground in general. A currently important topic, the search for a radioactive waste deposit, illustrates this relevance, as the crustal stress state is decisive for the short and long-term safety of a possible repository. For example, the integrity of the host rock due to the activation or reactivation of faults and associated fluid...

Differences in decompression of the high-pressure Cycladic Blueschist Unit (Naxos Island, Greece): what can inclusions tell us?

Alexandre Peillod , Jarosław Majka , Uwe Ring , Kirsten Drüppel , Clifford Patten , Andreas Karlsson , Adam Włodek & Elof Tehler
Determining the tectonic evolution and thermal structure of a tectonic unit that experiences a subduction-related pressure temperature (P-T) loop is challenging. Within a single unit, P-T conditions can vary from top to bottom which can be only revealed by detailed petrological work. We present micropetrological data of the middle section of the Cycladic Blueschist Unit (CBU) in Naxos, Greece, which indicate a different P-T loop than the top of the section. In the middle section,...

A global review of carbonatite-hosted fluid inclusions and the role of fluid release on carbonatite magma ascent

Benjamin Florian Walter , Johannes Giebel , Matthew Steele-MacInnis , Michael Marks , Jochen Kolb & Gregor Markl
Carbonatites crystallize from mantle-derived carbonate- and volatile-rich melts that exsolve large amounts of fluids during their ascent through and emplacement into the crust. A global review of available fluid inclusion data for carbonatitic systems from variable emplacement depths identified four types of fluid inclusions: (type-I) vapour-poor H2O-NaCl fluids with <50 wt.% salinity; (type-II) vapour-rich H2O-NaCl-CO2 fluids with <5 wt.% salinity; (type-III) multi-component fluids with high salinity without CO2; and (type-IV) multi-component fluids with high salinity...

Single borehole dilution tests using a permeable injection bag and a novel point-injection probe for the hydraulic characterization of karst aquifers

Nikolai Fahrmeier , Nadine Goeppert & Nico Goldscheider
Single borehole dilution tests are a method for characterizing groundwater monitoring wells or boreholes and can either be conducted as uniform injection throughout the entire saturated length or as point injection at one specific depth. By injecting a tracer into a borehole and measuring concentration profiles, flow horizons and possible vertical flow can be identified and quantified. Compared to conventional methods, such as flowmeters, SBDTs are cheaper and require less equipment, but allow important conclusions...

Wall rock contamination and mineralogical modifications in carbonatite dykes of the Palabora Complex, South Africa

R. Johannes Giebel , Benjamin F. Walter , Michael A.W. Marks & Gregor Markl
Contamination of carbonatite melts is often neglected due to a fast magma ascent and low liquidus temperatures. However, increased silicate mineral formation observed in numerous carbonatite occurrences world-wide requires an external Si introduction. Our study demonstrates that carbonatite dykes penetrating different lithologies of Palabora (South Africa) shows different modes of mineralogical modification. In particular Al and Si-rich lithologies show the most significant effects. Besides silicate mineral formation Si introduction may cause directly and indirectly variations...

Reasons for extreme Th/U zoning of zircon in magmatic rocks: examples from the Bushveld Complex

Armin Zeh , Dominik Gudelius & Allan H Wilson
Zircons of magmatic rocks can show enormous variations in Th/U ratios (0.2 to 100) and extreme Th/U zoning. We present data from felsic and mafic rocks of the Bushveld Complex in South Africa. Zircon grains in mafic cumulate rocks reveal Th/U ratios up to 70, those in felsic rocks barely exceed 1.0. In mafic rocks zircon mostly occur together with Rt-Bt-Kfs-Qtz in intercumulus domains, and crystallized during final magma cooling between 900 and 700°C, after...

FloodRisk: Earthquakes, uplift, and long-term liabilities – risk minimisation during mine flooding

Dennis Quandt , Michael Alber , Felix Allgaier , Benjamin Busch , Even Markus , Kasper Fischer , Wolfgang Friederich , Jonas Greve , Mathias Knaak , Birgit Müller , Thomas Niederhuber , Detlev Rettenmaier , Martina Rische , Thomas Röckel , Frank Schilling , Daniel Schröder , Olaf Ukelis , Malte Westerhaus , Roman Zorn & Benjamin Busch
Due to the cessation of coal mining in Germany, mine water management in the former coal districts is subject to change and of environmental and economic significance. Since there is no technical need to drain the abandoned coal mines, mine water levels rise. As a result, subsurface rock pore pressures rise changing the subsurface effective stress regime. This may induce local ground movements and activate mining-related and natural fault zones. In order to develop a...

Transport mechanisms of hydrothermal convection in faulted sandstone reservoir ----- Implications for kilometer-scale thermal anomalies in Piesberg quarry

Guoqiang Yan , Robert Egert , Maziar Gholami Korzani & Thomas Kohl
A transient 3D model obtained from the Piesberg quarry as an illustrative example is based on idealized structural models that characterize all geological features during Late Jurassic rifting (162 Ma) to infer possible transport mechanisms of fluids leading to the formation of kilometer-scale thermal anomaly. Three-dimensional numerical simulations on hydrothermal convection systems in the faulted sedimentary basins are investigated with the aim to assess the lateral heating capacity of hydrothermal convection systems in faults, using...

GeoLaB - Geothermal Laboratory in the Crystalline Basement

Thomas Kohl , Eva Schill , Judith Bremer , Günter Zimmermann , Olaf Kolditz & Ingo Sass
In Central Europe, the largest geothermal potential resides in the crystalline basement rock with important hotspots in tectonically stressed areas. To better harvest this energy form under sustainable, predictable and efficient conditions, new focused, scientific driven strategies are needed. Similar to other geo-technologies, the complex processes in the subsurface need to be investigated in large-scale facilities to ensure environmental sustainability. The proposed new underground research laboratory GeoLaB (Geothermal Laboratory in the Crystalline Basement) will address...

Nachbergbau: Chancen und Herausforderungen

Dennis Quandt , Tobias Rudolph & Christoph Hilgers
Bergbau im 21. Jahrhundert bedeutet auch Alt- und Nachbergbau, immer geknüpft an die Bewältigung post-montaner Herausforderungen und die Langzeit- und Zukunftsaufgaben. Hiermit einhergehend sind Fragestellungen zu den damit verbundenen Kosten und der Möglichkeit der Weiterentwicklung im Bereich der Standortintegrität und -überwachung. Zusätzlich ist die gesellschaftliche Akzeptanz (engl. „social license to operate“) von Bergbauprojekten immer ein Thema. Die Forderung der Öffentlichkeit nach mehr Informationen bei der Erkundung, der Erschließung, der Produktion und der Stilllegung eines Bergbaustandortes...

Ternary porosity systems: New perspectives for Buntsandstein geothermal reservoirs in the Upper Rhine Graben, SW Germany.

Ernst Kiefer , Birgit Müller & Frank Schilling
The clastic Lower Triassic Buntsandstein Formation in the Upper Rhine Graben of SW Germany and NE France has been identified as an attractive geothermal reservoir due to its fracture density and exceptionally high matrix porosity at depth levels of economic geothermal energy extraction. New petrophysical data from deep exploration wells reveal the existence of ternary porosity systems evolved during a multi-phase subsidence history and diagenesis especially at intra-graben structural highs. Primary elements of these porosity...

Fracture network characterization and DFN modelling of the Upper Carboniferous, Ruhr Area, Germany

Felix Allgaier, Benjamin Busch , Dennis Quandt , Thomas Niederhuber , Birgit Müller & Christoph Hilgers
Since coal mining in the Ruhr Area has been ceased, mine water drainage is gradually reduced leading to the rise of formation water and groundwater levels. Rising mine water levels increase the pore pressure and induce stress changes in the subsurface, which may reactivate natural and/or mining-related faults and fractures. As part of the interdisciplinary FloodRisk project, which aims to enhance the understanding of the geomechanical coupling of increased pore pressure and heterogeneous ground movements,...

Petrology and Geochronology of foidites and melilitites in SW Germany and E France

Thomas Binder , Benjamin F. Walter & Michael A. W. Marks
Foidites and melilitites are strongly SiO2-undersaturated rocks that form by extremely low degrees of partial melting of the metasomatically overprinted lithospheric mantle. In Central Europe, they occur in volcanic fields, dike swarms or as isolated stocks and diatremes. Our detailed study on foidites from SW Germany indicates two distinct age groups with marked differences in mineralogy and mineral chemistry: Based on in-situ U Pb age data (apatite, perovskite, zircon) a Miocene cohort (~ 9–19 Ma)...

Enhancing the contribution of closed systems to geothermal energy generation by increasing the ratio of generated power to the total length of wellbores

Morteza Esmaeilpour , Maziar Gholami Korzani & Thomas Kohl
Geothermal energy extraction through closed systems is a secure approach responding to the global heating demand without contaminating subsurface water and causing seismic events. However, the generated power of conventional closed systems is much lower than those of open systems. Therefore, this study is dedicated to planning a novel closed system, which can produce a significant amount of thermal power. For this purpose, the performance of a single closed-loop deep system with a lengthy horizontal...

The Kieshöhe carbonatites in SW-Namibia – the role of silicatic xenoliths for REE exploration

Benjamin Florian Walter , R. Johannes Giebel , Alan Marlow , Michael Marks , Gregor Markl & Jochen Kolb
Exploration of carbonatite-associated REE-deposits is challenging due to heterogeneous ore distribution and variable and often complex ore mineralogy. The Kieshöhe carbonatite in SW Namibia represents a subvolcanic occurrence hosting dolomite, calcite and ankerite carbonatite dykes, ring dykes and diatremes. Petrography, whole rock geochemistry and microXRF imaging provide insights into the role of silicate xenoliths for the REE mineralization in a subvolcanic environment. Xenolith-rich carbonatites are relatively REE-poor with only minor monazite mineralization, whereas xenolith-free carbonatites...

Simulation of flow through a single fracture calibrated with air permeameter measurements

Marco Fuchs , Sina Hale , Gabriel C. Rau , Kathrin Menberg & Philipp Blum
Determining fluid flow through natural fractures is an important task in many geoscience-related fields, such as geothermics. In order to estimate crucial parameters of single fractures controlling the flow and flow distribution, for example hydraulic apertures, hydro-mechanical numerical models have been established in recent years in addition to experimental methods. Although models enable a greater variety of analyses, they still require time-consuming processing before and after the simulation. This study presents a novel workflow for...

Seismic Monitoring of DeepStor: Using low-cost sensors for ambient noise correlation methods and Citizen Science

Johannes Käufl , Eva Schill & Thomas Kohl
DeepStor is an experimental facility with the goal to investigate High Temperature Aquifer Thermal Energy Storage (HT-ATES) systems at KIT Campus North. The operational seismic monitoring of DeepStor includes a network of five broadband and one borehole seismometer. In addition, we plan to install a scientific monitoring network with low-cost seismometers (such as the Raspberry Shake and the Quakesaver Hidra) to test innovative monitoring methods and for a Citizen Science project. Ambient noise tomography and...

Registration Year

  • 2022

Resource Types

  • Text


  • Karlsruhe Institute of Technology
  • University of Tübingen
  • University of the Free State
  • Technical University of Berlin
  • Technical University of Darmstadt
  • Helmholtz Centre Potsdam - GFZ German Research Centre for Geosciences
  • Helmholtz Centre for Environmental Research
  • Geologischer Dienst Nordrhein-Westfalen (Germany)
  • Gubkin Russian State University of Oil and Gas
  • Georgian Technical University