Study of sedimentary, diagenetic and structural effects on the genesis of a dolomitized reservoir body during the upper jurassic : application to Oxford-Portlandian Carbonate Platform of Causses Méjean (SE france)

The objective of this thesis is to investigate and understand the different sedimentary, diagenetic-compaction-burial, tectonic and paleohydrological factors making it possible to predict large dolomitic - reservoir complexes and their implications for the 3D heterogeneity of dolomitic-reservoir bodies. The objective is to establish a conceptual model for the prediction of dolomitic-reservoir bodies, following the example of the dolomitic bodies of Causses Méjean -France from the Upper Jurassic (Oxfordian to Portlandian).Understanding the phenomena of early and late dolomitisation and the physicochemical processes responsible for their development has not changed much over the last 15 years (Warren, 2000). Most research is limited to findings from observations in ancient or modern carbonate systems linking a sedimentary / diagenetic / structural context of a case study and the presence of dolomitic bodies. Very rarely are the physico-chemical processes originally identified. However, understanding the mechanisms responsible for the development of dolomites in ancient carbonate systems is of primary importance and of particular interest in the development and prediction of dolomitic reservoirsIn this thesis, the following points will be developed:1. Synthesis of the sedimentary, diagenetic, structural and reservoir studies of the Oxfordian-Kimmeridgian-Portlandian Causses platform,2. Definition of the relationships between sedimentary factors and dolomitic bodies - reservoirs,3. Definition of the relationships between chronological sequences of diagenetic transformations and dolomitic bodies - reservoirs,4. Definition of the relationships between the tectonic phenomena affecting the carbonate platform and the dolomitic bodies - reservoirs,5. Quantitative and qualitative study of the heterogeneity of reservoir properties within dolomitic bodies in relation to the type of dolomite,6. Define the mechanical deformations of the crystals of the different types of dolomite to specify the chronology of the diagenetic transformations with respect to the deformations and the burial.7. Define the paleo temperatures.