Research

Sustainable use of the environment, on and beneath the earth.
0Christoph Hilgers

Overview of our research

1. Summary 4. Diagenesis & Experiments - Reservoir quality prediction 7. Rock magnetics
2. Deformation 5. Digital rocks & digital fractures 8. Management
3. Rock- & Reservoir characterization 6. Reservoir heterogeneities: Porosity & Permeability 9. Outreach
10. Our tools
Summary

Our geology research at KIT  External Linkfocuses on deformation, diagenesis and rock magnetics.

  • We improve models on mechanical and chemical rock properties to better predict hetergeneties of reservoirs and storage sites in the subsurface. Our research on reservoir-geology generates the basis for innovations, technology transfer to industry ensured by our TTE Reservoir-Geology at KIT Campus Transfer GmbH External Link.

Our management interests cover processes, quality and risk of the supply-chain as well as triple-I projects.

  • We analyze processes and techno-economical utilization concepts for energy and mineral resources to identify strategic alternatives. This covers interdisciplinary technical and economical aspects on hydrogen, (green) methane, CO2, pumped storage und underground mines.
  • Our triple-I projects (international-interdisciplinary-intercultural) cover transnational higher education and exchange, and the set-up of higher educations institutions. Our projects in Oman, Morocco, Tunisia and Egypt include the establishment of a new private university GUtech, the mutual development of education (TwinTraining) in groundwater and medicine, geothermal and mining, as well as an exchange with research institutions.

Outreach covers earth system processes, as well as topics on the supply of energy, raw materials and storage in an STEEPLE environment.

Our innovations contribute to the efficient exploration and use of renewable energy, hydrocarbons, raw materials and subsurface storage.

Fig. 1. Transparent thin section with blue colored pore space under optical light microscope with plane (left) and crossed (right).

Our applied and fundamental research couples different scales in the broad field of reservoir geology. Reservoirs are temporary or permanent, natural or man-made subsurface storage sites. These produce geoenergy, i.e. fossil energy such as natural gas and oil, ground heat / geothermal energy, and raw materials such as nitrogen and helium gas, and store energy and other substances temporally or permanently.

Deformation

We develop models on brittle and ductile deformation. Digital fracture models and -distributions in reservoirs are developed from contact-free digitalization and analysis of rocks such as UAV, Lidar and hyperspectral imaging to better constrain the anisotropy and heterogeneity of 3D rock volumes (Fig. 2). Digital fractures from horizonal wells are subjected to in-situ stress to calculate conductive joints (Fig. 3). Microstructures in salt can be used to deduce creep rates for subsurface- and well integrity from microstructures. Deformation processes in salt and claystone as well as nano-tectonics in hardrocks open new methods of rock analysis.

Fig. 2. 3D laser scan (grey) of the large quarry Piesberg near Osnabruck. The gently dipping bedding planes (green), the tectonic normal fault (blue) form the structure of the reservoir analog. The laser scan (grey) with trees on the upper berm (white arrow). The fracture pattern (joints) are colored according to their spatial orienation (yellow, blue, red) and populated in the geological model to calculate the flow properties of the reservoir (from Wüstefeld et al. 2018).

Becker et al 2019 Stressed facture horizontal well

Fig. 3. Fracture distribution and orientation along horizontal well in fractured carbonates subsalt. Color-coded the potential of each fracture to open (upper row) and slip (lower rock) (from Becker et al 2019).

Rock- & reservoir characterization

We characterize the reservoir to deduce the reasons of anisotropy of the geological rock body to better understand variable rock properties caused by structural, sedimentary and chemical processes. Outcrops, core from boreholes as well as mines of the quarry and pit industry are studied worldwide. Characterization includes, but is not limited to, deformation, diagenesis (""structral Diagenesis") (Fig. 4). Resevoir characterization includes mineral fabric, diagenesis, rock magnetics, spectral GR as well as porosity and permeability analyses. Our seismic velocities on plugs can deduce porosity and geomechanical properties. With our sGR, vp and hadheld XRF we couple rock data from analogs and cores with well logs. Based on such data we deduce models for other reservoirs.


Fig. 4. Transparent thin section with blue colored pore space under optical light microscope with plane (left) and crossed (rght) polarizers shows secondary pore space due to dissolved feldspar grain. Associated quartz migration and formation of kaolinite clay minerals are replaced by illite clay minerals (from Busch et al. 2017).


Diagenesis & Experiments - Reservoir-Quality Prediction

We predict the cementation of pore- and fracture space and associated physico-chemical alteration and predict porous and fractured reservoir quality using numerical and experimental approaches. Our custom-made see-through transparent and bulk microreactors reflect reactive fluid flow of geofluids in rocks and improve the prediction of microstructural rock ateration. Deformation processes in top seal rocks such as salt can be used to derive creep rates to deduce subsurface and well stability based on microstructures.

Fig. 5. Subsidence model and temperature scenario for 5 different wells matches with modelled illite cementation and experimentally measured K-Ar ages of authigenic illites. We thus can use the amount of quartz and illite cements to validate different thermal models, and thus better constrain the calcualted pore volume and permeability at depth (from Busch et al. 2018).

Digital Rocks & Digital Fractures

We develop new digital tools with CMS Prof. Nestler within KIT and beyond. Our research aims to better predict rock properties by improving the understanding of underlying processes. Rocks are digitized and calibrated for numerical simulations of mulitphase flow and cementation. We drive the modeling with digital rocks jointly with our colleagues.

Fig. 6. Digital rock models in mulitphase flow of gas-fromation water predict flow channels and permeability tensors for different sandstones of mono- and polycrystalline quartz grains (from Prajapati et al. 2020).

Reservoir heterogeneities - Porosity and permeability

We measure single phase flow porosity and permeability up to reservoir conditions of 150°C and 50 MPa. This includes plugs and permeability tensors on cubes. The p-T petrophysical variations are coupled with macro- and microscopic, sedimentological and structural parameters to deduce new dependencies on lateral and vertical heterogeneities of sedimentology, mineral fabric and structural geology.

Rock magnetics

Rock magnetic fabric and its anisotropy is studied from sedimentary to basement rocks and is applied on a wide range of geological processes. This ranges from microstructural analyses to stratigraphic correlations. Our broad experience in the field of rock magnetics contributes to fundamental geological processes and well correlations.

Kontny et al 2018 HiRes-SEM shocked magnetite

Fig. 7. High-resolution SEM of shocked magnetites. Left: Dissolution/degassing of Fe-Mg-Al silicate. Middle: Dashed lines show shear bands of 5 GPa shocked magnetite. Right: 120° grain boundaries at 20 GPa shocked magnetite sample (from Kontny et al. 2018).

Management

We consider the full value chain from exploration to storage of energy- and raw material deposits using the STEEPLE environment. STEEPLE stands for the macro-environmental factors social, technological, economic, environmental, poitical, legal and ethical. We consider reilient supply of construction- and metal raw materials and associated industrial processes (Fig. 8).

GDP population and metal growth

Fig. 8. a) The global population will grow by another 3 bio. until 2060, however global wealth (assoicated with energy- and raw mateiral consumption) increases more rapidly. b) The demand of metals such as copper and europium (a rare earth metal) both grow per captia and in total volume (Hilgers et al. 2021).

Interdisciplinary projects range from technical to economic studies. Previous studies covered risk management of longwall mining, technical aspects of pipeline infrastructure, pump storage plants on dismantled open pit lignite mines, natural gas supply models for Eastern Europe with imported US shale gas, real options approaches for compressed air energy or economic feasability of power-to-gas load balancing (hydrogen & green methane) (Fig. 9).

Power to gas load balancing hydrogen green methane

Fig. 9. Principal outline for economic calculations for P2X hydrogen and green methane gas (Budny et al. 2015).

Our experience covers the planning and operation of private higher education institutions overseas, and the development and management of interdisciplinary training courses in close cooperation with industry. Previous projects focused on the implementation of the German University of Technology GUTech LLC (Fig., info) in beautiful Muscat, Oman, and training courses on geothermal and fossil energy, medicine and mining in Tunisia, Morocco together with Egypt.

GUtech University Oman

Fig. 10. The German University of Technology in Muscat, Oman.

Tools: CrystalBall, MiniTab, MS Project & Visio and special tools.

Outreach

We aim to contribute to unravel the fuzzy world of facts and fiction, needs and wishful thinking in our field of expertise. Geosciences is not only the science of a continuously changing earth, but the science ensuring the sustainable supply of georesources for human life and industrial development.

We disseminate research on earth system processes to media and news, and share knowledge with the related industry and authorities. We collaborate with our partners in Arabia, Azerbaijan, Egypt, India, Japan, Morocco, Russia, USA and Tunisia and are happy to expand our network.

Fig. 11. Overview of our geology research.

Our tools

Reservoir characterization of rocks. Tools: spectral gamma ray, petrography transmitted light microscopes, cathodoluminescence microscopy, automatic point counters, He pycnometry for porosity, permeability up to 50 MPa confining pressure and 150°C, WellCad, EasyCore etc.

We use rock magnetic methods for a lot of different scientific questions on rock magnetic propoerties. This covers the (i) Correlation of lithology and magnetic susceptibility, (ii) Determination of the carriers of magnetic properties and (iii) Correlation with geological processes (magmatism, metamorphism, sedimentation) and understanding of geological processes (emplacement mechanisms, fluid-rock-interactions, etc.). Examples of ongoing projects.

Digital subsurface data and field analogs. Tools: AgiSoft, ArcGIS, Becip FranLab (FracaFlow), CloudCompare, EasyCore (for teaching), Eclipse, FaroScene, FracPaQ, MatLab, Move, Petrel (incl. Eclipse), PetroMod, TouchStone, WellCad.

Improvement of contact-free analyses of fracture surfaces and mineralogical heterogeneities at quarry wall, cores, tunnels, caves to establish rock qualities and wall stabilities for optimized mining, stability, and a better understanding of 3D heterogeneities. Tools: terrestrial laserscanning, hyperspectral, UAV with various detectors

Physico-chemical experients: custom built transparent see-through and bulk microreactors

Digital models of 3D sedimentary bodies at outcrop scale, fracture networks and porosity-permeability variations in the field as basis for flow simulations. Tools: Laser scanning, image analyses.

Analyses and quantification of nucleation processes, cementation rates and different crystal morphologies at core- & pore scale, using high-resolution imaging techniques and experiments. Tools: Petrography, cathodoluminescence, fluorescence, experiments, isotopes, poro-perm, WellCad, EasyCore