A5027062930- Seismic Imaging and Inversion Techniques
- Geophysical Methods and Applications
- Seismic Waves and Analysis
- Hydraulic Fracturing and Reservoir Analysis
- Geophysical and Geoelectrical Methods
- Groundwater flow and contamination studies
- Drilling and Well Engineering
- earthquake and tectonic studies
- Rock Mechanics and Modeling
- Seismology and Earthquake Studies
- Reservoir Engineering and Simulation Methods
- Hydrology and Sediment Transport Processes
- Geotechnical and Geomechanical Engineering
- CO2 Sequestration and Geologic Interactions
- Flow Measurement and Analysis
- Underwater Acoustics Research
- Landslides and related hazards
- Geothermal Energy Systems and Applications
- Hydrocarbon exploration and reservoir analysis
- Hydrology and Watershed Management Studies
- Cryospheric studies and observations
- Quantum Computing Algorithms and Architecture
- Climate change and permafrost
- Geological Modeling and Analysis
- Microwave Imaging and Scattering Analysis
Lufthansa (Germany)
2021-2024
Quantum Design (Germany)
2023
ETH Zurich
2011-2021
Earth Science Institute of the Slovak Academy of Sciences
2017
FORS – Swiss Centre of Expertise in the Social Sciences
2016
Aarhus University
2013-2015
Lawrence Berkeley National Laboratory
2011-2013
Leibniz Institute for Applied Geophysics
2010-2011
The University of Adelaide
2010-2011
University of Lausanne
2010-2011
Abstract. In this contribution, we present a review of scientific research results that address seismo-hydromechanically coupled processes relevant for the development sustainable heat exchanger in low-permeability crystalline rock and introduce design situ Stimulation Circulation (ISC) experiment at Grimsel Test Site dedicated to studying such under controlled conditions. The shows on reservoir stimulation deep geothermal energy exploitation has been largely based laboratory observations,...
Predictive groundwater modeling requires accurate information about aquifer characteristics. Geophysical imaging is a powerful tool for delineating properties at an appropriate scale and resolution, but it suffers from problems of ambiguity. One way to overcome such limitations adopt simultaneous multitechnique inversion strategy. We have developed methodology characterization based on structural joint multiple geophysical data sets followed by clustering form zones subsequent zonal...
Electrical resistivity tomography (ERT) is based on solving a Poisson equation for the electrical potential and characterized by good sensitivity only in vicinity of electrodes used to gather data. To provide more information ERT, we propose an image-guided or structure-constrained inversion apparent This approach uses structural obtained directly from guiding image. image can be drawn high resolution geophysical method propagation (e.g. migrated seismic ground penetrating radar images)...
ABSTRACT With the potential of high temporal and spatial sampling capability utilizing existing fiber-optic infrastructure, distributed acoustic sensing (DAS) is in process revolutionizing geophysical ground-motion measurements, especially remote urban areas, where conventional seismic networks may be difficult to deploy. Yet, for DAS become an established method, we must ensure that accurate amplitude phase information can obtained. Furthermore, as spreading into many different application...
ABSTRACT Cross‐hole radar tomography is a useful tool for mapping shallow subsurface electrical properties viz. dielectric permittivity and conductivity. Common practice to invert cross‐hole data with ray‐based tomographic algorithms using first arrival traveltimes cycle amplitudes. However, the resolution of conventional standard inversion schemes ground‐penetrating (GPR) limited because only fraction information contained in used. The can be improved significantly by full‐waveform that...
The hydrogeological properties and responses of a productive aquifer in northeastern Switzerland are investigated. For this purpose, 3D crosshole electrical resistivity tomography (ERT) is used to define the main lithological structures within (through static inversion) monitor water infiltration from an adjacent river. During precipitation events subsequent river flooding, increases. As consequence, characteristics infiltrating can be as natural tracer delineate preferential flow paths...
Determining groundwater flow paths of infiltrated river water is necessary for studying biochemical processes in the riparian zone, but their characterization complicated by strong temporal and spatial heterogeneity. We investigated to what extent repeat 3D surface electrical resistance tomography (ERT) can be used monitor transport a salt-tracer plume under close natural gradient conditions. The aim estimate velocities pathways at site located within system adjacent perialpine Thur River...
Reliable high-resolution 3-D characterization of aquifers helps to improve our understanding flow and transport processes when small-scale structures have a strong influence. Crosshole ground penetrating radar (GPR) is powerful tool for characterizing due the method's sensitivity porosity soil water content. Recently, novel GPR full-waveform inversion algorithm was introduced, which here applied used by inverting six crosshole cross-sections collected between four wells arranged in square...
Time‐lapse geophysical monitoring and inversion are valuable tools in hydrogeology for changes the subsurface due to natural forced (tracer) dynamics. However, resulting models may suffer from insufficient resolution, which leads underestimated variability poor mass recovery. Structural joint using cross‐gradient constraints can provide higher‐resolution compared with individual inversions we present first application time‐lapse data. The results a synthetic field vadose zone water tracer...
Abstract. River restoration projects have been launched over the last two decades to improve ecological status and water quality of regulated rivers. As most restored rivers are not monitored at all, it is difficult predict consequences or analyze why restorations fail successful. It thus necessary implement efficient field assessment strategies, for example by employing sensor networks that continuously measure physical parameters high spatial temporal resolution. This paper focuses on...
Abstract. To characterize the stress field at Grimsel Test Site (GTS) underground rock laboratory, a series of hydrofracturing and overcoring tests were performed. Hydrofracturing was accompanied by seismic monitoring using network highly sensitive piezosensors accelerometers that able to record small events associated with metre-sized fractures. Due potential discrepancies between hydrofracture orientation estimates from overcoring, it essential obtain high-precision hypocentre locations...
Abstract Multiple meter‐scale hydraulic fracturing (HF) experiments were executed in the crystalline rock at Grimsel Test Site, Switzerland. The effect of HF on transmissivity has been quantified with tests before and after each experiment. We observe enhancement 2 to 3 orders magnitude a change dominant flow regime most tests. From microseismicity induced by HF, we do not systematic correlation between event numbers, frequency‐magnitude distribution, or maximum magnitude. However, radii...
Abstract High-resolution 3D geological models are crucial for underground development projects and corresponding numerical simulations with applications in e.g., tunneling, hydrocarbon exploration, geothermal exploitation mining. Most based on sparse data sampled pointwise or along lines (e.g., boreholes), leading to oversimplified model geometries. In the framework of a hydraulic stimulation experiment crystalline rock at Grimsel Test Site, we collected 15 boreholes using variety methods...
Abstract. We performed a series of 12 hydraulic stimulation experiments in 20m×20m×20m foliated, crystalline rock volume intersected by two distinct fault sets at the Grimsel Test Site, Switzerland. The goal these was to improve our understanding processes associated with high-pressure fluid injection used for reservoir creation enhanced or engineered geothermal systems. In first six experiments, pre-existing fractures were stimulated induce shear dilation and enhance permeability. Two types...
Optimization is a crucial task in various industries such as logistics, aviation, manufacturing, chemical, pharmaceutical, and insurance, where finding the best solution to problem can result significant cost savings increased efficiency. Tensor networks (TNs) have gained prominence recent years modeling classical systems with quantum-inspired approaches. More recently, TN generative-enhanced optimization (TN-GEO) has been proposed strategy which uses generative efficiently sample valid...
Fluid that fills boreholes in crosswell electrical resistivity investigations provides the necessary contact between electrodes and rock formation but it is also source of image artifacts standard inversions do not account for effects boreholes. The distortions can be severe large contrasts borehole fluid diameters. We have carried out 3D finite-element modeling using an unstructured-grid approach to quantify magnitude different contrasts, diameters, electrode configurations. Relatively...
Often in geophysical monitoring experiments time-lapse inversion models vary too smoothly with time, owing to the strong imprint of regularization. Several methods have been proposed for focusing spatiotemporal changes model parameters. In this study, we present two generalizations minimum support norm, which favour compact and can be adapted specific problem requirements. Inversion results from synthetic direct current resistivity that mimic developing plumes show scheme significantly...
Abstract Fluid pressure within the Earth's crust is a key driver for triggering natural and human‐induced seismicity. Measuring fluid evolution would be highly beneficial understanding underlying driving mechanisms supporting seismic hazard assessment. Here we show that velocities monitored on 20‐m scale respond directly to changes in pressure. Our data volumetric strain resulting from effective stress sensed by velocity, while shear dislocation not. We are able calibrate velocity against...