THE CLOSED ANR PROJECT MAXWELL ON MICROWAVE IMAGING SYSTEM : PROSPECTIVES
Mathew Yedlin for the MAXWELL project
Quality criteria of 3D Models : example of the Rustrel case study.
3D geomodelling approaches aim at building 3D models of geological structures, conditioned to soft (trends, etc.) and hard (local data points, etc.) data. Since uncertainties exist (few data, lack of knowledge, etc.), stochastic approaches allows geoscientists to characterize these uncertainties through a series of plausible and equiprobable generated 3D models, on which descriptors (transfer functions) will be studied. The objectives of such a strategy is to determine how a priori uncertainties make a posteriori uncertainties varied. However, in many applications, stochastic approaches are not suited or expected. In a deterministic context, the obtained 3D models often represent a reconstruction of the structures compiling or managing these different constraints. Depending on the used approach, the uncertainties and the discrepancy between the different data sources, the obtained 3D model will not simultaneously and similarly fit all the input data but parts of them. In this context, the "quality" of a model is often questioned and criteria to estimate this "quality" are necessary to define. In this paper, it is proposed to address some of these criteria from the real case study of the Rustrel formation.
Reservoir properties acquisition in tight carbonate : Example of lower Cretaceous hemipelagic limestones of southern part of Voconitan Basin (Middle Durance Zone, SE France)
Pierre-Olivier Bruna, Guglielmi Yves, Lamarche Juliette, Floquet Marc, Bertrand Catherine, Fournier François, Sizun Jean-Pierre, Gallois Arnaud, Marié Lionel, Hollender Fabrice
Understanding tight reservoirs behaviour, characterised by low values of porosity and permeability of intact rock, is a major scientific and economic challenge, involving applications to fresh water management and industrial risks control. In hydrogeology, tight rocks are only considered for their fracture permeability, storage capacity of intact rocks being considered as negligible. Nevertheless, this is inconsistent with deep unconventional gas and petroleum resources where tight reservoirs can produce significant quantities of fluid. The key question that we address is the role of this tight intact rock in the fluid diffusion process. This problem is of importance to better understand fluid flow both in the near surface aquifers and in the deep sedimentary basin formations.
STRATIGRAPHIC ANATOMY AND DIAGENESIS OF A BARREMIAN – APTIAN CARBONATE PLATFORM (MONTS-DE-VAUCLUSE, SE FRANCE)
The reservoir-scale stratigraphic anatomy and the diagenesis of a Barremian-Aptian carbonate platform (Mont-de-Vaucluse, South-East France) is based on 1) high-resolution measured sections in outcrops, 2) detailed microfacies analyses, 3) paleoenvironmental interpretations, 4) biostratigraphy, 5) sequence stratigraphic interpretations, 6) diagenetical and geochemical analyses.
Dissimilar properties of a small fault zone in a carbonate reservoir and their impact on the pressurization and leakage associated with CO2 injection
Pierre Jeanne, Yves Guglielmi, Frédéric Cappa, pdf file
This paper focuses on a small fault zone (too small to be detected by geophysical imaging) affecting a carbonate reservoir composed of porous and low-porous layers. In a gallery located at 250-m depth in the Underground Low Noise Laboratory, hydraulic properties of a 20-m thick section of the reservoir affected by the studied fault are characterized by structural measurements and by ahydraulic injection in boreholes. Main result is that the damage zone displays contrasted permeability values (up to two orders of magnitude) inherited from the differential alteration of the intact rock layers. To characterize the impact of these hydraulic properties variations on the flow of fluids, numerical simulations of supercritical CO2 injections were performed with the TOUGH2 code. It appears, the permeability variations inside the fault zone favor the appearance of high fluid overpressure located in the layers having the highest permeability and storativity.