A seminar by:  Gabriel Godefroy at ENSG, Nancy, room G201

On: Friday, 3rd of February, 1:00 pm.

Au cours de ma thèse, je m’intéresse à la modélisation des failles et des incertitudes associées. Je présenterais deux méthodes de construction de structures faillées. Ces méthodes intègrent un modèle numérique des déformations associés à la faille afin de produire des géométries cohérentes. La prise en compte des incertitudes lors de l'interprétation des observations de failles sera également abordée.

A seminar by:  Pierre Anquez at ENSG, Nancy, room G201

On: Friday, 27th of January, 1:00 pm.

In geomodeling, a sealed geological model is needed to partition the subsurface in several watertight rock volumes by interpreted structural geometries.This geological boundary representation can then be used as input for meshing, then flow and geomechanical modeling. However, it is still difficult to easily generate sealed geological models. Whether geomodels are created using implicit surfaces or explicit surfaces, small gaps and/or overlaps may exist between surfaces preventing the generation of volumetric meshes. There is also a need for geomodel simplification such as small feature removal to avoid the generation of 3D mesh with a poor quality. In this talk, I will try to answer to the following questions. How to automatically repair a geomodel with inconsistencies? How to simplify a geomodel to help further unstructured 3D meshing? In this respect, I will present the method I am developing to solve these issues and some first results.

A seminar by:  Modeste Irakarama at ENSG, Nancy, room G201

On: Friday, 20th of January, 1:00 pm.

Conceptual uncertainty is inherent to structural modeling, a single seismic image can lead to multiple structural interpretations. Can we use seismic data to evaluate the relative quality of possible candidate interpretations? This will be the subject of this seminar. In this talk, I will first give assumptions and propose conditions under which such a problem can be solved; then I'll present an example. We will then close the seminar with an open discussion and exchange of ideas about the proposed method.

A seminar by:  Jonathan Edwards at ENSG, Nancy, room G201

On: Friday, 13th of January, 1:00 pm.

Je vais revenir sur mes travaux de thèse et les organiser de façon logique pour préparer mon manuscrit de thèse et la présentation de ma soutenance.

Je vais d'abord présenter le problème de la corrélation stratigraphique, puis faire un état de l'art. Ensuite, je présenterai quelques règles de corrélation, et je détaillerai ma méthode utilisant un modèle forward comme modèle d'entraînement. Puis, je présenterai une technique pour gérer les ambiguïtés de la corrélation multi-puits en construisant la colonne stratigraphique de la zone d'étude. Enfin, je montrerai quelques résultats.

A seminar by:  Guillaume Caumon at ENSG, Nancy, room G201

On: Friday, 6th of January, 1:00 pm.

Principles of transdimensional inversion and a summary of Jihane Belhadj’s PhD.

A seminar by:  Gabriel Godefroy at ENSG, Nancy, room G201

On: Friday, 2nd of December, 1:00 pm.

Le meeting annuel de la SEG s'est tenu cette année à Dallas, Texas. Au court de ce séminaire, je vous présenterais ce que j'ai appris sur des sujets divers tels que la Full Waveform Inversion, la corrélation sismique puits, le calcul d'attributs sismiques, ou la prise en compte des incertitudes. Le séminaire ne sera pas exhaustif, mais j'essaierais de retranscrire quelque présentations intéressantes.

A seminar by:  Antoine Mazuyer at ENSG, Nancy, room G201

On: Friday, 9th of December, 1:00 pm.

We open the path to the absolute value of the stress by proposing an integrated method to estimate such a value in reservoirs and overburden before oil and gas production. The computed stress is constrained by wellbore data using an inverse approach. Assuming that the mechanical behavior is linear elastic, we perturb the boundary conditions to produce an admissible (i.e. satisfying the equilibrium equations) stress states. Misfit between stress computation and wellbore data minimization is done using CMA-ES, an evolutionary algorithm suitable for ill-conditionned problem. We validate and test the behaviour of our method through a synthetic case. I have worked on this synthetic case the previous months to run very fast inversion using a quadratic mesh with a beautiful mesh !

A seminar by:  Francois Bonneau at ENSG, Nancy, room G201

On: Friday, 25th of November, 1:00 pm. 

The seminar aims at presenting some rules to structure and organize your projects. I will also present some tools designed for project management and collaborative work. I will talk about Bitbucket (a web-based hosting service for projects) and Trello (web-based numerical board for collaboration and communication).

A seminar by:  Antoine Mazuyer and Modeste Irakarama at ENSG, Nancy, room G201

On: Friday, 18th of November, 1:00 pm. 

Today's computers are parallel friendly, allowing us to reduce the amount of time we spend running computations. In this two-part introductory seminar, we will discuss tow different "scales" of parallel computing: (1) parallel computing for small to medium problems that can be achieved on a personal computer, (2) and parallel computing for large problems that usually require a cluster.

The first part, parallel computing on a personal computer, will focus on general purpose GPU (GPGPU) computing. GPGPU is a big part of modern parallel computing, both on personal computers and on clusters. We will present some basic examples to illustrate the efficiency, in terms of execution time, to be expected from GPGPU.

The second part deals with parallel computing on CPU clusters; it will focus on the use of Message Passing Interface (MPI). MPI is a C/C++/Fortran library that is used by nodes (a node can be seen as one computer) to communicate between each other. If you use MPI, parts of your code will be executed at the same time by every node, which requires a particular attention to the distribution of memory. We will use basic examples to illustrate these concepts.