Modélisation géologique 3D et hydrodynamique appliquées aux réservoirs carbonatés karstiques : caractérisation des ressources en eau souterraine de l'Unité du Beausset (SE France)

Abstract : The aim of this PhD thesis is to provide an original approach for the characterization of karstic carbonate reservoirs that integrates 3D geological modeling and hydrodynamics. The 3D geological model stands for the structural compartmentalization of the reservoir and the hydrodynamics provide dynamic properties for the understanding of the fluid flow. This methodology is applied to the characterization of the groundwater resources of the Beausset Unit (SE France). The study area is a syncline composed of nearly 3000 m of Mesozoic sedimentary rocks, which age from late Triassic to Upper Cretaceous. These rocks, which are mainly carbonates, crop out over an area of 650 km² and have known several phases of fracturation and karstification. This study is divided in four parts: (1) synthesis of existing data, (2) 3D geological modeling, (3) study of hydrodynamics, and (4) integration of static and dynamic data in order to discuss the characterization of the groundwater resources in the Beausset Unit. The existing data on stratigraphy, lithology, petrophysical properties, karstology and hydrogeology allow the definition of seven lithostratigraphic intervals that have been chosen for modeling. These intervals represent the vertical compartmentalization of the reservoir: each interval has an unique combination of karst and rocks properties. The building of the 3D geological model of the Beausset Unit relies on new structural cross-sections based on field survey and literature data. In the field, new hydrogeological data have been obtained: seven springs have been continuously monitored for their CTD (specific Conductivity, Temperature and Depth -pressure-) parameters, an almost exhaustive sampling of springs for their hydrochemistry and flow measurement surveys. The CTD recordings have been analyzed as time series in order to infer the flow units and the reservoir units. Two new methods have been proposed from this data: a new classification of karstic aquifers based on the impulse response of the springs (MIB method) and a measure of the karst functionality by the conversion of CTD series into color spectral bands (KaRGB method). The hydrochemical analyses have provided the hydrogeological compartmentalization by natural tracing. The flow measurement surveys have allowed quantifying the groundwater fluxes at the year scale. The characterization of the static and dynamic properties of the Beausset Unit leads to the upscaling of these properties for pointing out the key horizons for groundwater tapping. New groundwater resources are proposed by spring tapping and by well drilling. The wellbore implantation proposition relies on a new method of multiparametric mapping of well potentiality (Wi index method). This method is based on the use of the 3D geological model as a framework for the synthesis of static and dynamic quality of each lithostratigraphic interval. The global methodology used in this PhD thesis allows the integration of observations, data and results, with various origins and resolution, in the same numeric framework for the characterization of carbonate karstic reservoirs.
Complete list of metadatas

https://tel.archives-ouvertes.fr/tel-00830331
Contributor : Bruno Arfib <>
Submitted on : Tuesday, June 4, 2013 - 5:00:47 PM
Last modification on : Thursday, September 12, 2019 - 8:54:08 PM
Long-term archiving on : Thursday, September 5, 2013 - 4:24:27 AM

Identifiers

  • HAL Id : tel-00830331, version 1

Citation

Arnaud Fournillon. Modélisation géologique 3D et hydrodynamique appliquées aux réservoirs carbonatés karstiques : caractérisation des ressources en eau souterraine de l'Unité du Beausset (SE France). Interfaces continentales, environnement. Aix-Marseille Université, 2012. Français. ⟨tel-00830331⟩

Share

Metrics

Record views

1245

Files downloads

5243