Conference Agenda

Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).

 
 
Session Overview
Session
6.1-1 Applications in 3D Geological Modelling
Time:
Wednesday, 22/Sept/2021:
1:30pm - 3:00pm

Session Chair: Rouwen Johannes Lehné, HLNUG
Session Chair: Roland Baumberger, Swiss Geological Survey
Session Chair: Stephan Steuer, Bundesanstalt für Geowissenschaften und Rohstoffe

Session Abstract

Over the last decades, 3D geological modelling has become a standard in hydrocarbon exploration and production, has been adopted and is developing towards a systematic effort by geological surveys, and is on the verge of being able to properly handle the structurally complex settings in which the mining sector operates. New, exciting possibilities are arising and new application domains are opening up, which challenges geomodellers to integrate data and methods from different domains (e.g. remote-sensed and subsurface data), and to deliver integrated content (e.g. urban underground infrastructure and geology). In this process, several hurdles must be overcome, i.e., developing standards, harmonization, integration of data, storing and sharing content in a structured manner, and developing services. In the process challenges are manifold, and so are the solutions.This session therefore is looking for contributions addressing the wide field of geological 3D-modelling and associated topics such as data modelling & data storage and sharing systems. We especially encourage the younger generation to present and are glad to announce a special block within the session that is dedicated to honor selected student degree theses and reward them with a cash prize. For more details please visit the website of the section Geoinformatics (www.fgi-dggv.de). 


Presentations
1:30pm - 1:45pm

Visual KARSYS – a web service for modelling karst aquifers in 3D

Arnauld Malard1, Pierre-Yves Jeannin1, Manfred Vogel2, Simon Lopez3

1SISKA, Swiss Institute for Speleology and Karst Studies, rue de la Serre 68 – CH2300 La Chaux-de-Fonds; 2i4ds Institute of 4D Technologies, Fachhochschule Nordwestschweiz, Bahnhofstrasse 6, CH5210 Windisch; 3BRGM, 3 avenue Claude-Guillemin, 45000 Orléans

A 3D web-service has been developed for the modeling and for the management of karst aquifers and related groundwater resources. Visual KARSYS allows users to build explicit models of karst aquifers via a 3D geological modeller (gmLib Python library) and a series of tools (i.e. algorithms) which provide characteristics of groundwater bodies by applying hydraulic principles.

Visual KARSYS is designed for geologists or hydrogeologists working for public institutions or private companies, but also for administration or decision makers facing various issues in karst environments: groundwater resources, natural hazards, geothermal energy, civil engineering, etc. Outputs from Visual KARSYS (data, models and resulting documentation) can be shared between users for being consulted or edited.

The web-service is available at visualkarsys.com and it is currently free-of-charge and we encourage users to use it. In March 2021, more than 425 users already registered and ~150 persons attended the training courses.

The Visual KARSYS project is supported by the Swiss Federal Office for Environment via the grant for the promotion of environmental technology (2016-2019, UTF 537.13.16).



1:45pm - 2:00pm

Geohub: Sustainable Geomodeling

Georg Semmler, Helmut Schaeben, Heinrich Jasper

TU Bergakademie Freiberg, Germany

Digital 3D geomodels are becoming a routine tool for geoscientific research, engineering and surveying. Most models incorporate various datasets into a simplified virtual representation of reality.
Turning the process of model building into something sustainable, so that future users can build on the results and insights provided by a given model raises a number of questions:

  • How can we assure that other users can reconstruct the same model given the required information?
  • How do we ensure that repetition of a construction using the same information yields the same geomodel, such that the process itself is reproducible?

With Geohub we present a theoretical framework to represent a construction process of a geomodel. We represent a construction process as directed acylic hypergraph. Each node of this hypergraph represents a dataset used or generated as part of the construction process.
Each hyperedge represents a construction step, that transforms a set of input datasets into a single possible intermediate output dataset. Construction steps consists of a generic representation, which is executable with a computer.
This enables us to repeat a construction process to:

  • check if the construction of a geomodel is reproducible by comparing the results of different repetitions
  • update a geomodel with new input data by repeating the construction using the new dataset
  • generate different realisations of the same geomodel built by input dataset based on stochastic distributions.

Eventually we present an implementation of this framework ensuring repeatability of the construction process and reproducibility of the geomodels constructed in this way.



2:00pm - 2:15pm

Use of three-dimensional implicit geological modeling to assist groundwater management of a karst aquifer

Fernando Mazo D'Affonseca1,2, Olaf Cirpka2, Michael Finkel2

1TIMGEO GmbH; 2University of Tübingen

Although 3-D geological modeling has been mostly employed in the prospection and exploitation of ores, oil and gas, its importance in the field of groundwater resources management is considerably increasing. Traditional 3-D geological modeling schemes are based on explicit digitization of geological units and structures. Progresses in 3-D interpolation techniques have favored the emergence of implicit modeling, in which geological surfaces are automatically created from hard data and interpretation. The major benefit of implicit modeling relies on its speed. In this work the implicit modeling approach was applied to conceptualize and model a karst aquifer in southwest Germany, using digital elevation data, geological maps, borehole logs, and geological interpretation. Dip and strike measurements as well as soil-gas surveys of mantel-borne CO2 were conducted to verify the existence of a postulated fault. The geological model was automatically translated into a numerical groundwater flow model that was calibrated to match measured hydraulic heads, spring discharge rates, and flow directions observed in tracer tests. Refinements of the numerical model’s spatial parametrization was iteratively conducted, using the geological model for visualization of interim simulations. As the results of numerical modeling may support or contradict the 3-D geological model, additional geological insights can be eventually gained in this way. The geological model allowed the proper assessment of the system geometry and the definition of boundary conditions. The numerical groundwater flow model was applied to evaluate the potential risks from limestone quarries to local water supply wells.



2:15pm - 2:30pm

High Precision 3D Modelling of Complex Geological Structures: An Approach Combining Different Types of Software for Maximum Efficiency

Tatjana Thiemeyer, Manuela Stehle, Christian Dresbach, Matthias Beushausen

Federal Institute for Geosciences and Natural Resources (BGR)

3D modelling of complex salt structures for the purpose of final disposal of radioactive waste requires a particulary high degree of precision. In this perspective, conventional geological 3D modelling software fails to produce satisfying results. For this reason, BGR uses the software openGEO that allows the integration of all types of basic geoscientific data. In particular, for the management of ground-penetrating radar measurements a group of specific tools has been developed as part of the software package.

However, compared to conventional 3D geological modelling software openGEO is more labour-intensive. This is because model surfaces are not created by an algorithmic procedure. Quite the contrary, surfaces need to be constructed manually by considering and incorporating all accessible data.

Especially for areas within the model where data are limited and/or geological structures are simple in terms of geometry, the idea is, that the combination of openGEO with software that is based on an interpolation algorithm would facilitate the modelling process. As a first approach, simple geological structures were modelled in SKUA-GOCAD and merged with the model in openGEO. Here we present first results from combining both software packages in the described way. We used salt structures and their complex inner layers for testing the developed workflow. Thus, we are here introducing a more efficient approach compared to the sole use of openGEO and add a new level of flexibility. The workflow can potentially be applied to the 3D modelling in other geologically complex settings where a high degree of precion is required.



2:30pm - 2:45pm

The deeper subsurface of Lower Saxony - Developing a generalised 3D geological model from heterogeneous and inconsistent data

Sabine Sattler, Marcus Helms, Cornelia Wangenheim, Jennifer Ziesch

State Authority for Mining, Energy and Geology (LBEG), Germany

The creation and application of 3D geological models has become increasingly important within the geological surveys in recent years. In the joint project TUNB (Tieferer Untergrund Norddeutsches Becken - Deeper Underground North German Basin), the geological surveys of northern Germany together with the Federal Institute for Geosciences and Natural Resources (BGR) created a coordinated and largely border-harmonised 3D geological model of the North German Basin for their respective state areas.

The objective of this presentation is to describe the approach to develop a generalised 3D geological model from the base Zechstein to the Tertiary of Lower Saxony based on heterogeneous and inconsistent data within this project. The data basis for the current model was the predecessor model GTA3D, digitally available borehole data, depth migrated 2D and 3D seismic data and supplementary data such as thickness and structural maps of lithostratigraphic units. 3D geological modelling was carried out with Emerson SKUA-GOCAD, taking into account the project-related generalisation specifications and geological plausibility. The problem of inconsistencies occurring in the input data due to their different sources, quantity, and quality could not be solved by automated procedures. Instead, this was often subject to the geological expertise of the modeller, who took into account the regional geological conditions to weight the data and create a model that is as free of contradictions as possible. We demonstrate how the integration of new data led to changes in the geometry of salt structures and lithostratigraphic horizons with respect to the predecessor model.



2:45pm - 3:00pm

3D lithofacies modelling and quantitative fault seal analysis in the Altmark region (North German Basin)

Jacob Waechter, Christian Olaf Mueller, Alexander Malz

Geological survey of Saxony-Anhalt, Germany

Attributed 3D volumetric models are important tools for geothermal exploration, subsurface storage of natural gases and waste and for risk management (e.g. contamination of ground water or induced seismicity). Of special interest are lithological attributes, which reveal important evidence on characteristics of deep aquifers and reservoir rocks and support project planning.

Therefore, we created attributed 3D volumetric models, which base on a detailed 3D structural geological model of the Altmark region (North German Basin) comprising 31 horizons from base Zechstein to Quaternary. For this purpose, information from lithologic-paleogeographic maps was transferred to the volume models by defining categorial properties. Shale fractions could be qualitatively estimated from the petrographic descriptions and quantitatively confirmed using gamma ray logs. Subsequently, a fault seal analysis was performed on the basis of the lithofacies model. Calculation of the juxtaposition parameter and smear gauge ratio (SGR) provides information on the faults transmissivity and the clay smearing of permeable fault segments.

The resulting attributed 3D models reveal essential information on geometry and characteristics of deep aquifers and reservoir rocks, as well as potential fluid pathways or sealing functions across faults in the Altmark region. Furthermore, extracted lithological information and attributed fault cutoff lines allow a detailed representation of subsurface parameters and the fault network on 2D maps. The results thus form the basis for large information systems and databases providing FAIR and easy to use information for further planning and prospection efforts.