3D modelling of the dolerite dyke network within the Siilinjärvi phosphate deposit

Non peer reviewe

Innovative Approaches to 3D GIS Modeling for Volumetric and Geoprocessing Applications in Subsurface Infrastructures in a Virtual Immersive Environment

As subsurface features remain largely ‘out of sight, out of mind’, this has led to challenges when dealing with underground space and infrastructures and especially so for those working in GIS. Since subsurface infrastructure plays a major role in supporting the needs of modern society, groups such as city planners and utility companies and decision makers are looking for an ‘holistic’ approach where the sustainable use of underground space is as important as above ground space. For such planning and management, it is crucial to examine subsurface data in a form that is amenable to 3D mapping and that can be used for increasingly sophisticated 3D modeling. The subsurface referred to in this study focuses particularly on examples of both shallow and deep underground infrastructures. In the case of shallow underground infrastructures mostly two-dimensional maps are used in the management and planning of these features. Depth is a very critical component of underground infrastructures that is difficult to represent in a 2D map and for this reason these are best studied in three-dimensional space. In this research, the capability of 3D GIS technology and immersive geography are explored for the storage, management, analysis, and visualization of shallow and deep subsurface features

PySubdiv 1.0: open-source geological modeling and reconstruction by non-manifold subdivision surfaces

Sealed geological models are commonly used as an input to process simulations, for example, in hydrogeological or geomechanical studies. Creating these meshes often requires tedious manual work, and it is therefore difficult to adjust a once-created model. In this work, we propose a flexible framework to create and interact with geological models using explicit surface representations. The essence of the work lies in the determination of the control mesh and the definition of semi-sharp-crease values, which, in combination, enable the representation of complex structural settings with a low number of control points. We achieve this flexibility through the adaptation of recent algorithms from the field of computer graphics to the specific requirements of geological modeling, specifically the representation of non-manifold topologies and sharp features. We combine the method with a particle swarm optimization (PSO) approach to enable the automatic optimization of vertex position and crease sharpness values. The result of this work is implemented in an open-source software (PySubdiv) for reconstructing geological structures while resulting in a model which is (1) sealed/watertight, (2) controllable with a control mesh and (3) topologically similar to the input geological structure. Also, the reconstructed model may include a lower number of vertices compared to the input geological structure, which results in reducing the cost of modeling and simulation. In addition to enabling a manual adjustment of sealed geological models, the algorithm also provides a method for the integration of explicit surface representations in inverse frameworks and the consideration of uncertainties.</p

Integration of multiple data types in 3-D immersive virtual reality (VR) environments

Intelligent sensors have begun to play a key part in the monitoring and maintenance of complex infrastructures. Sensors have the capability not only to provide raw data, but also provide information by indicating the reliability of the measurements. The effect of this added information is a voluminous increase in the total data that is gathered. If an operator is required to perceive the state of a complex system, novel methods must be developed for sifting through enormous data sets. Virtual reality (VR) platforms are proposed as ideal candidates for performing this task-- a virtual world will allow the user to experience a complex system that is gathering a multitude of sensor data and are referred as Integrated Awareness models. This thesis presents techniques for visualizing such multiple data sets, specifically - graphical, measurement and health data inside a 3-D VR environment. The focus of this thesis is to develop pathways to generate the required 3-D models without sacrificing visual fidelity. The tasks include creating the visual representation, integrating multi-sensor measurements, creating user-specific visualizations and a performance evaluation of the completed virtual environment

Geological constraints on surface-based models through development of Rapid Reservoir Modelling

Surface-based geological modelling (SBM) represents all geological heterogeneity that impacts the spatial distribution of petrophysical properties using surfaces. To create surface-based models, rules are required to govern how surfaces interact such that resulting models are geologically sound. Previous studies used implicit rules or assumptions, often with the requirement that surfaces are created in stratigraphic or hierarchical order. A comprehensive set of explicit and universal rules to govern the interaction of stratigraphic surfaces has yet to be formalised. In this thesis, seven operators are presented that define how stratigraphic surfaces interact for geological modelling such that universal geological rules are obeyed. The operators can be applied through any SBM technique and are independent of geological process, scale and setting. The operators are demonstrated using three hand-drafted examples of siliciclastic and carbonate strata, at centimetre to kilometre scales, using outcrop, seismic and conceptual input data. These universal stratigraphic operators are then implemented in 3D in the sketch-based interface and modelling (SBIM) research prototype software Rapid Reservoir Modelling (RRM). Three case studies are presented using examples of siliciclastic and carbonate strata from different depositional environments, at multiple scales, using seismic, outcrop, and well log data to constrain and guide the sketches. The case studies demonstrate the operators and three different techniques for moving from 2D sketch to 3D model, revealing the flexibility and broad applicability of the operators for SBIM of stratigraphy. Lastly, the stratigraphic operators are leveraged in RRM to create structural models. Test cases are a conjugate fault model and a physical model of a salt-influenced passive margin. Gaps in the applicability of stratigraphic operators for ‘sketch-what-you-see’ structural modelling and diagenesis are identified and future updates to RRM are recommended. RRM is the first SBIM software that allows rapid prototyping of geological reservoir models and represents a step-change for the field.Open Acces