Impacts of changing conditions on far-field radionuclide evolution: background and goals of a newly funded DFG-RFBR project.

2020 ◽  
Author(s):  
Fabien Magri ◽  
Thomas Nagel ◽  
Axel Liebscher ◽  
Victor Malkovsky
Keyword(s):  
Porous Media ◽  
Groundwater Flow ◽  
Open Source ◽  
Large Scale ◽  
Numerical Models ◽  
Basic Research ◽  
Crystalline Rock ◽  
Coupled Processes ◽  
Far Field ◽  
Long Time

<p>To date, the most secure, technically feasible and internationally accepted solution for the safe management of Radioactive Waste (RW) is burial in deep host rock units, also referred to as disposal in a deep geological repository (DGR). For this purpose, it is mandatory to select a site in a hydrogeological setting which provides sufficiently safe natural conditions for waste isolation from groundwater flow over long time periods (up to 1 Ma).</p><p>However, over such a long time period, external factors (e.g. climate change) and intrinsic basin features (e.g. tectonics), here referred to as changing conditions, will impact the hydrological (H), thermal (T), mechanical (M) and chemical (C) state of the entire system. Therefore, it is crucial to better understand the impacts of changing conditions on far-field radionuclide mobilization and behavior in order to select the most suitable DGR for RW disposal.</p><p>Multiphysics simulators offer powerful tools that couple groundwater flow (H), transport of heat (T), as well as geochemical reactions (C) in a deforming solid framework (M). These coupled THM-C numerical models can provide evaluations for performance and safety assessment of a DGR at different scales. However, a limited number of studies so far addressed the far-field evolution of radionuclides under the changing conditions listed above.</p><p>The newly funded German Science Foundation (DFG) and the Russian Foundation for Basic Research (RFBR) project “INFRA” (NA1528/2-1 and MA4450/5-1; 2020-2022) aims to investigate the impacts of (i) glaciation, (ii) permafrost and (iii) tectonic events on the coupled boundaries that control large-scale groundwater flow near hypothetical waste repositories. For this purpose, the open source simulator OpenGeoSys [1,2] will be applied using available data from selected areas of the Yeniseisky Site in Russia [3].</p><p>Though the context of this study is related to RW issues, the outcomes of INFRA will be of interest for any field of geosciences that deals with large-scale simulations of coupled processes under transient boundary conditions.</p><p> </p><p>[1] Kolditz, O., Bauer, S., Bilke, L., Böttcher, N., Delfs, J. O., Fischer, T., … Zehner, B. (2012). OpenGeoSys: an open-source initiative for numerical simulation of thermo-hydro-mechanical/chemical (THM/C) processes in porous media. Environmental Earth Sciences, 67(2), 589–599. https://doi.org/10.1007/s12665-012-1546-x</p><p>[2] Bilke, L., Flemisch, B., Kalbacher, T., Kolditz, O., Helmig, R., & Nagel, T. (2019). Development of Open-Source Porous Media Simulators: Principles and Experiences. Transport in Porous Media, 130(1), 337–361. https://doi.org/10.1007/s11242-019-01310-1.</p><p>[3] Laverov, N., Yudintsev, S., Kochkin, B., Malkovsky V. (2016). The Russian Strategy of using Crystalline Rock as a Repository for Nuclear Waste. Elements, 12(4), 253–256. https://doi: 10.2113/gselements.12.4.253  </p>

scholarly journals PorePy: an open-source software for simulation of multiphysics processes in fractured porous media

2020 ◽  
Author(s):  
Eirik Keilegavlen ◽  
Runar Berge ◽  
Alessio Fumagalli ◽  
Michele Starnoni ◽  
Ivar Stefansson ◽  
...  
Keyword(s):  
Porous Media ◽  
Open Source ◽  
Open Source Software ◽  
Fractured Rocks ◽  
Fractured Reservoirs ◽  
Simulation Software ◽  
Coupled Processes ◽  
Fracture Networks ◽  
Flow And Transport ◽  
Multiphysics Problems

Abstract Development of models and dedicated numerical methods for dynamics in fractured rocks is an active research field, with research moving towards increasingly advanced process couplings and complex fracture networks. The inclusion of coupled processes in simulation models is challenged by the high aspect ratio of the fractures, the complex geometry of fracture networks, and the crucial impact of processes that completely change characteristics on the fracture-rock interface. This paper provides a general discussion of design principles for introducing fractures in simulators, and defines a framework for integrated modeling, discretization, and computer implementation. The framework is implemented in the open-source simulation software PorePy, which can serve as a flexible prototyping tool for multiphysics problems in fractured rocks. Based on a representation of the fractures and their intersections as lower-dimensional objects, we discuss data structures for mixed-dimensional grids, formulation of multiphysics problems, and discretizations that utilize existing software. We further present a Python implementation of these concepts in the PorePy open-source software tool, which is aimed at coupled simulation of flow and transport in three-dimensional fractured reservoirs as well as deformation of fractures and the reservoir in general. We present validation by benchmarks for flow, poroelasticity, and fracture deformation in porous media. The flexibility of the framework is then illustrated by simulations of non-linearly coupled flow and transport and of injection-driven deformation of fractures. All results can be reproduced by openly available simulation scripts.

scholarly journals The seismo-hydro-mechanical behaviour during deep geothermal reservoir stimulations: open questions tackled in a decameter-scale in-situ stimulation experiment

2017 ◽  
Author(s):  
Florian Amann ◽  
Valentin Gischig ◽  
Keith Evans ◽  
Joseph Doetsch ◽  
Reza Jalali ◽  
...  
Keyword(s):  
Rock Mass ◽  
Geothermal Energy ◽  
Numerical Models ◽  
Test Site ◽  
Crystalline Rock ◽  
Coupled Processes ◽  
Small Scale ◽  
Intermediate Scale ◽  
Grimsel Test Site

Abstract. In this contribution we present a review of scientific research results that address seismo-hydro-mechanical coupled processes relevant for the development of a sustainable heat exchanger in low permeability crystalline rock and introduce the design of the In-situ Stimulation and Circulation (ISC) experiment at the Grimsel Test Site dedicated to study such processes under controlled conditions. The review shows that research on reservoir stimulation for deep geothermal energy exploitation has been largely based on laboratory observations, large-scale projects and numerical models. Observations of full-scale reservoir stimulations have yielded important results. However, the limited access to the reservoir and limitations in the control on the experimental conditions during deep reservoir stimulations is insufficient to resolve the details of the hydro-mechanical processes that would enhance process understanding in a way that aids future stimulation design. Small scale laboratory experiments provide a fundamental insights into various processes relevant for enhanced geothermal energy, but suffer from 1) difficulties and uncertainties in upscaling the results to the field-scale and 2) relatively homogeneous material and stress conditions that lead to an over-simplistic fracture flow and/or hydraulic fracture propagation behaviour that is not representative for a heterogeneous reservoir. Thus, there is a need for intermediate-scale hydraulic stimulation experiments with high experimental control that bridge the various scales, and for which access to the target rock mass with a comprehensive monitoring system is possible. Only few intermediate-scale hydro-shearing and hydro-fracturing experiments have recently been performed in a densely instrumented rock mass. No such measurements have been performed on faults in crystalline basement rocks. The In-situ Stimulation and Circulation (ISC) experiment currently performed in a naturally fractured and faulted crystalline rock mass at the Grimsel Test Site (Switzerland) is designed to address open research questions, which could not be investigated in the required detail so far. Two hydraulic injection phases were executed to enhance the permeability of the rock mass: a hydro-shearing phase and then a hydraulic fracturing phase. During the injection phases the rock mass deformation across fractures and within intact rock, the pore pressure distribution and propagation and the micro-seismic response were monitored at a high spatial and temporal resolution.

scholarly journals A stream-power law for glacial erosion and its implementation in large-scale landform-evolution models

2021 ◽  
Author(s):  
Stefan Hergarten
Keyword(s):  
Sediment Transport ◽  
Large Scale ◽  
Numerical Models ◽  
Stream Power ◽  
Glacial Erosion ◽  
Simple Formulation ◽  
Landform Evolution ◽  
Fluvial Erosion ◽  
Numerical Effort ◽  
Long Time

Abstract. Modeling glacial landform evolution is more challenging than modeling fluvial landform evolution. While several numerical models of large-scale fluvial erosion are available, there are only a few models of glacial erosion, and their application over long time spans requires a high numerical effort. In this paper, a simple formulation of glacial erosion which is similar to the fluvial stream-power model is presented. The model reproduces the occurrence of overdeepenings, hanging valleys, and steps at confluences at least qualitatively. Beyond this, it allows for a seamless coupling to fluvial erosion and sediment transport. The recently published direct numerical scheme for fluvial erosion and sediment transport can be applied to the entire domain, where the numerical effort is only moderately higher than for a purely fluvial system. Simulations over several million years on lattices of several million nodes can be performed on standard PCs. An open-source implementation is freely available as a part of the landform evolution model OpenLEM.

scholarly journals A coupled wave–3-D hydrodynamics model of the Taranto Sea (Italy): a multiple-nesting approach

2016 ◽  
Vol 16 (9) ◽  
pp. 2071-2083 ◽  
Author(s):  
Maria Gabriella Gaeta ◽  
Achilleas G. Samaras ◽  
Ivan Federico ◽  
Renata Archetti ◽  
Francesco Maicu ◽  
...  
Keyword(s):  
High Resolution ◽  
Open Source ◽  
Large Scale ◽  
Numerical Models ◽  
Sea Levels ◽  
Circulation Patterns ◽  
Forecasting System ◽  
Using Data ◽  
Oceanographic Model ◽  
Coupled Wave

Abstract. The present work describes an operational strategy for the development of a multiscale modeling system, based on a multiple-nesting approach and open-source numerical models. The strategy was applied and validated for the Gulf of Taranto in southern Italy, scaling large-scale oceanographic model results to high-resolution coupled wave–3-D hydrodynamics simulations for the area of Mar Grande in the Taranto Sea. The spatial and temporal high-resolution simulations were performed using the open-source TELEMAC suite, forced by wind data from the COSMO-ME database, boundary wave spectra from the RON buoy at Crotone and results from the Southern Adriatic Northern Ionian coastal Forecasting System (SANIFS) regarding sea levels and current fields. Model validation was carried out using data collected in the Mar Grande basin from a fixed monitoring station and during an oceanographic campaign in October 2014. The overall agreement between measurements and model results in terms of waves, sea levels, surface currents, circulation patterns and vertical velocity profiles is deemed to be satisfactory, and the methodology followed in the process can constitute a useful tool for both research and operational applications in the same field and as support of decisions for management and design of infrastructures.

scholarly journals A coupled wave-3D hydrodynamics model of the Taranto Sea (Italy): a multiple-nesting approach

2016 ◽  
Author(s):  
Maria Gabriella Gaeta ◽  
Achilleas G. Samaras ◽  
Ivan Federico ◽  
Renata Archetti
Keyword(s):  
High Resolution ◽  
Open Source ◽  
Large Scale ◽  
Numerical Models ◽  
Sea Levels ◽  
South Italy ◽  
Circulation Patterns ◽  
Forecasting System ◽  
Using Data ◽  
Coupled Wave

Abstract. The present work describes an operational strategy for the development of a multiscale modelling system, based on a multiple–nesting approach and open–source numerical models. The strategy was applied and validated for the Gulf of Taranto in South Italy, scaling large–scale oceanographic model results to high–resolution coupled wave – 3D hydrodynamics simulations for the area of Mar Grande in Taranto Sea. The spatial and temporal high – resolution simulations were performed using the open–source TELEMAC suite, forced by wind data from the COSMO–ME database, boundary wave spectra from the RON Buoy at Crotone, and results from the Southern Adriatic Northern Ionian coastal Forecasting System (SANIFS) regarding sea levels and current fields. Model validation was carried out using data collected in the Mar Grande basin from a fixed monitoring station and during an oceanographic campaign in October 2014. The overall agreement between measurements and model results in terms of waves, sea levels, surface currents, circulation patterns and vertical velocity profiles is deemed to be satisfactory, and the methodology followed in the process can constitute a useful tool for both research and operational applications on the same field and and as support of decisions for management and design of infrastructures.

The FEBEX Project. General Overview

1997 ◽  
Vol 506 ◽  
Author(s):  
F. Huertas ◽  
J.L. Santiago
Keyword(s):  
Large Scale ◽  
Numerical Models ◽  
Near Field ◽  
Thermal Response ◽  
Crystalline Rock ◽  
Full Scale ◽  
Deep Geological Disposal ◽  
Heating Test ◽  
Large Scale Tests ◽  
Term Performance

ABSTRACTUnderstanding the near-field evolution of a deep geological disposal system for HLW is crucial for assessing its long term performance and, therefore, safety. For that reason ENRESA devised the FEBEX Project, a Full Scale Engineered Barriers Experiment in crystalline rock. The project consists of a full-scale “in-situ” heating test, a large-scale laboratory mock-up and supporting materials tests, and modelling.Even though the object of the project is to contribute to the search for methods of behaviour and of safety analyses for a repository, other subinvestigations have been/are being included. The stated objectives are to demonstrate the procedures of constructing an engineered barrier system (EBS), especially the fabrication, handling, and installation of bentonite blocks (buffer) at an almost industrial scale, to improve and validate the numerical models for thermo-hydro-mechanical behaviour, and to investigate the geochemical processes that are produced in the buffer including canister corrosion, as well as the generation and transport of gas. Since early 1997, with the commencement of the heating phase, both large-scale tests have been fully operative. At this point it can be said that the demonstration objective of constructing the EBS has been successfully achieved. The measured thermal response of the buffer follows the pattern predicted in the preliminary modelling. The saturation rate of the buffer and associated mechanical processes are being continuously monitored.

scholarly journals GO2OGS 1.0: a versatile workflow to integrate complex geological information with fault data into numerical simulation models

2015 ◽  
Vol 8 (11) ◽  
pp. 3681-3694 ◽  
Author(s):  
T. Fischer ◽  
D. Naumov ◽  
S. Sattler ◽  
O. Kolditz ◽  
M. Walther
Keyword(s):  
Numerical Simulation ◽  
Groundwater Flow ◽  
Open Source ◽  
Computer Aided Design ◽  
Numerical Models ◽  
Simulation Models ◽  
Geological Information ◽  
Visualization Toolkit ◽  
Aided Design ◽  
Scientific Questions

Abstract. We offer a versatile workflow to convert geological models built with the ParadigmTM GOCAD© (Geological Object Computer Aided Design) software into the open-source VTU (Visualization Toolkit unstructured grid) format for usage in numerical simulation models. Tackling relevant scientific questions or engineering tasks often involves multidisciplinary approaches. Conversion workflows are needed as a way of communication between the diverse tools of the various disciplines. Our approach offers an open-source, platform-independent, robust, and comprehensible method that is potentially useful for a multitude of environmental studies. With two application examples in the Thuringian Syncline, we show how a heterogeneous geological GOCAD model including multiple layers and faults can be used for numerical groundwater flow modeling, in our case employing the OpenGeoSys open-source numerical toolbox for groundwater flow simulations. The presented workflow offers the chance to incorporate increasingly detailed data, utilizing the growing availability of computational power to simulate numerical models.

scholarly journals Modelling of CO2 storage in geological formations with DuMux, a free-open-source numerical framework. A possible tool to assess geological storage of carbon dioxide in Romania

2019 ◽  
Vol 85 ◽  
pp. 07002 ◽  
Author(s):  
Alexandru Tatomir ◽  
Alexandru-Nicolae Dimache ◽  
Iancu Iulian ◽  
Martin Sauter
Keyword(s):  
Carbon Dioxide ◽  
Open Source ◽  
Large Scale ◽  
Numerical Models ◽  
Co2 Storage ◽  
Geological Storage ◽  
Biological Phenomena ◽  
Viable Solution ◽  
Multi Phase Flow ◽  
Multi Phase

Geological storage of carbon dioxide represents a viable solution to reduce the greenhouse gases in the atmosphere. Romania has initiatives to build a large-scale integrated CO2 capture and storage demonstration project and find suitable on-shore and off-shore CO2 storage locations. Numerical simulators are essential tools helping the design process. These simulators are required to be capable to represent the complex thermo-hydro-mechanical-chemical and biological phenomena accompanying the geological CO2 storage such as, multi-phase flow, compositional effects due to dissolution of CO2 into the brine, non-isothermal effects due to cold CO2 injection, geomechanical effects, mineralization at the reservoir-scale. These processes can be simulated accurately and efficiently with DuMux (www.dumux.org), a free- and open-source simulator. This article presents and reviews briefly these mathematical and numerical models.

scholarly journals A new look at sunspot formation using theory and observations

2016 ◽  
Vol 12 (S327) ◽  
pp. 46-59
Author(s):  
I. R. Losada ◽  
J. Warnecke ◽  
K. Glogowski ◽  
M. Roth ◽  
A. Brandenburg ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Large Scale ◽  
Solar Surface ◽  
Deep Structure ◽  
Numerical Models ◽  
Solar Physics ◽  
Stratified Turbulence ◽  
Flux Tubes ◽  
Large Scale Magnetic Field ◽  
Long Time

AbstractSunspots are of basic interest in the study of the Sun. Their relevance ranges from them being an activity indicator of magnetic fields to being the place where coronal mass ejections and flares erupt. They are therefore also an important ingredient of space weather. Their formation, however, is still an unresolved problem in solar physics. Observations utilize just 2D surface information near the spot, but it is debatable how to infer deep structures and properties from local helioseismology. For a long time, it was believed that flux tubes rising from the bottom of the convection zone are the origin of the bipolar sunspot structure seen on the solar surface. However, this theory has been challenged, in particular recently by new surface observation, helioseismic inversions, and numerical models of convective dynamos. In this article we discuss another theoretical approach to the formation of sunspots: the negative effective magnetic pressure instability. This is a large-scale instability, in which the total (kinetic plus magnetic) turbulent pressure can be suppressed in the presence of a weak large-scale magnetic field, leading to a converging downflow, which eventually concentrates the magnetic field within it. Numerical simulations of forced stratified turbulence have been able to produce strong super-equipartition flux concentrations, similar to sunspots at the solar surface. In this framework, sunspots would only form close to the surface due to the instability constraints on stratification and rotation. Additionally, we present some ideas from local helioseismology, where we plan to use the Hankel analysis to study the pre-emergence phase of a sunspot and to constrain its deep structure and formation mechanism.

scholarly journals The seismo-hydromechanical behavior during deep geothermal reservoir stimulations: open questions tackled in a decameter-scale in situ stimulation experiment

Solid Earth ◽  
2018 ◽  
Vol 9 (1) ◽  
pp. 115-137 ◽  
Author(s):  
Florian Amann ◽  
Valentin Gischig ◽  
Keith Evans ◽  
Joseph Doetsch ◽  
Reza Jalali ◽  
...  
Keyword(s):  
Rock Mass ◽  
Geothermal Energy ◽  
Numerical Models ◽  
Test Site ◽  
Crystalline Rock ◽  
Coupled Processes ◽  
Small Scale ◽  
Homogeneous Material ◽  
Grimsel Test Site

Abstract. In this contribution, we present a review of scientific research results that address seismo-hydromechanically coupled processes relevant for the development of a sustainable heat exchanger in low-permeability crystalline rock and introduce the design of the In situ Stimulation and Circulation (ISC) experiment at the Grimsel Test Site dedicated to studying such processes under controlled conditions. The review shows that research on reservoir stimulation for deep geothermal energy exploitation has been largely based on laboratory observations, large-scale projects and numerical models. Observations of full-scale reservoir stimulations have yielded important results. However, the limited access to the reservoir and limitations in the control on the experimental conditions during deep reservoir stimulations is insufficient to resolve the details of the hydromechanical processes that would enhance process understanding in a way that aids future stimulation design. Small-scale laboratory experiments provide fundamental insights into various processes relevant for enhanced geothermal energy, but suffer from (1) difficulties and uncertainties in upscaling the results to the field scale and (2) relatively homogeneous material and stress conditions that lead to an oversimplistic fracture flow and/or hydraulic fracture propagation behavior that is not representative of a heterogeneous reservoir. Thus, there is a need for intermediate-scale hydraulic stimulation experiments with high experimental control that bridge the various scales and for which access to the target rock mass with a comprehensive monitoring system is possible. The ISC experiment is designed to address open research questions in a naturally fractured and faulted crystalline rock mass at the Grimsel Test Site (Switzerland). Two hydraulic injection phases were executed to enhance the permeability of the rock mass. During the injection phases the rock mass deformation across fractures and within intact rock, the pore pressure distribution and propagation, and the microseismic response were monitored at a high spatial and temporal resolution.

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