AGW - Structural Geology

Research

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

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. Research generates the basis for our innovations, its 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. 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, as well as methods to implement transnational higher education and of related higher 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 study fractures and fracture distributions in reservoirs and develop 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).

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).

Diagenesis - 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) and petrophysical analyses such as rock magnetics, sGR as well as porosity and permeability analyses. Our research adresses underlying processes to better predict rock properties.


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 - Reservoir-Quality Prediction

We predict the cementation of pore- and fracture space and associated physico-chemical alteration 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 our colleagues 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  KIT-CMS Prof. Nestler.

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).

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. Hilgers et al.).

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.

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) (Abb. Budny et al. 2015).

Power to gas load balancing hydrogen green methane

Fig. 9. Principal outline for economic calculations for P2X hydrogen and green methane gas.

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

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, 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 

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