Speaker(s): Antoine Mazuyer

Date: Friday 27th of April

Location: room G201, ENSG, Nancy

Abstract:

In this seminar, I will talk about the usage of elasticity properties to model the mechanical behaviour of the faults. I will present some preliminar results on simple synthetic models in order to integrate this method in efficient inverse approaches.

Speaker(s): Margaux Raguenel

Date: Friday 20th of April

Location: room G201, ENSG, Nancy

Abstract:

Understanding the physical processes occurring in a geothermal reservoir is a key point to make decisions about resources exploitation developments. In the frame of the GEOTREF project in Basse-Terre, Guadeloupe, data have been acquired and interpreted by geologists and geophysicists. Numerical models are now build to assess geological scenarios in accordance with the obtained data and determine potential areas of interest. In this seminar, I will present my work on these numerical models. First, models have been designed to evaluate the impact of several parameters on heat transfers and fluid flows. These parameters have been incorporated in models to determine the realism of different geological scenarios explaining the presence of heat in Bouillante. To go further in the representation of complex geological and physical models, a tool linking two specialized libraries has then been designed and tested on several applications. The last part of this presentation will be a brainstorming on the potential use of this new tool and its application to the reservoir of Basse-Terre.

Speaker(s): Modeste Irakarama

Date: Friday 13th of April

Location: room G201, ENSG, Nancy

Abstract:

Seismic waveform inversion methods are techniques for quantitative subsurface imaging by fitting synthetic data to observed data. Waveform inversion has received a lot of attention over the last couple of decades, mainly due advances in high performance computing resources, among other things. In this seminar, I attempt to give a practical introduction to linearized and nonlinear waveform inversion. The word practical, here, is synonymous with "computer implementation". I focus on computer implementation, mostly, as the underlying theory can be found in many textbooks. Questions and comments are encouraged during and/or after the presentation.

 
Date: Friday 23rd of March

Location: room G201, ENSG, Nancy
 
Abstract:
 
Les grilles sont sans doute une des manières les plus simples de représenter des données, ce qui permet notamment de les utiliser pour optimiser certains calculs scientifiques de manière très efficace. Je me propose donc de vous présenter certaines utilisations possibles de celles-ci, ainsi que l'implémentation de grilles cartésiennes que j'ai effectué dans le logiciel RINGMesh, et la bibliothèque d'algorithmes spécifiques associés RINGGrid que j'ai codée en prélude de ma thèse, pendant mon CDD au sein de l'équipe RING.
 
Date: Thursday 22nd of March

Location: room G201, ENSG, Nancy
 
Abstract:
 
Hexahedral meshing of general domains is the ultimate challenge in mesh generation. The most promising methods are indirect, they combine the elements of a initial tetrahedral mesh to create prisms, pyramids and hexaedra. They build a mesh composed of a majority of hexahedra. In this talk, I wll present the main steps of indirect meshing, the latest results of our team and the remaining challenges to reach real time hex-dominant mesh generation.

Speaker(s): Pierre Anquez

Date: Friday 23rd of February

Location: room G201, ENSG, Nancy

Abstract:

Meshing a 3D geological model is often essential in integrative subsurface modeling, but it is often a time-consuming task that typically requires a lot of user interaction. The difficulty is double: (i) the invalidity of the models and (ii) their geometrical complexity. The principal cause of invalidity for 2D or 3D boundary models is the non-watertightness. However, watertightness is generally required by meshing methods. In addition, the inherent geometrical complexity of geological models (due to e.g. thin layers, unconformities, or small fault displacements) strongly constrains the quality of the mesh to generate. To have a good mesh quality, one solution is to modify the geological model by merging locally or displacing its boundaries before generating the mesh.
In this seminar I will present a method I am currently developing to detect and fix geological model invalid and complex features. I model these features by a graph providing a formal framework to operate and correct the input model. The possible operations to fix the geometrical and topological issues are equivalent to graph elementary operations. This seminar will also be an opportunity to present the GJK algorithm, a fast algorithm to compute convex shape intersection and distance, I intend to use in geomodel invalid feature detection process.

Speaker(s): Yves Frantz

Date: Friday 16th of March

Location: room G201, ENSG, Nancy

Abstract:

Les graphes sont des structures mathématiques ayant de nombreuses applications, notamment en algorithmique. Je me propose de vous faire une présentation très synthétique de ces derniers et de leurs applications. Je présenterai ensuite RINGGraph, la bibliothèque que j'ai codée lors de mon CDD au sein de l'équipe RING.

Speaker(s): François Bonneau

Date: Friday 2nd of March

Location: room G201, ENSG, Nancy

Speaker(s): Virginie Gaullier (Prof. Université de Lille, LOG)

Date: Wednesday 28th of February

Location: room G201, ENSG, Nancy