The Annot Sandstone Outcrops (French Alps): Architecture Description as Input for Quantification and 3D Reservoir Modeling
Philippe Joseph, Nathalie Babonneau, Aline Bourgeois, Gilles Cotteret, Rémi Eschard, Blaise Garin, Didier Granjeon, Olivier Lerat, Christian Ravenne, Olinto Gomes de Souza, François Guillocheau, Jean-Marie Quemener, 2000. "The Annot Sandstone Outcrops (French Alps): Architecture Description as Input for Quantification and 3D Reservoir Modeling", Deep-Water Reservoirs of the World, Paul Weimer
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The Eocene-Oligocene Annot Sandstone of South East France is a sand-rich turbiditic system, up to 1000 m thick, which was deposited in several parallel and tectonically controlled sub-basins. For reservoir characterization purposes, three kilometer-scale outcrop areas were studied in detail, resulting in bed-scale, 2D and 3D architecture descriptions.
The western Annot-Chalufy confined sub-basin, probably fed from a fan-delta located near Saint Antonin, shows a downstream evolution from very coarse-grained erosive channels (developing lateral terrace deposits) to tabular channelized or depositional lobes separated by thick heterolithic levels acting as major permeability barriers.
The eastern Sanguinière narrow sub-basin was probably fed by multiple braided deltas at the border of the Alpine mountain chain to the east. In a ramp setting, coarsening then fining-upward sequences register the increase then decrease in flow energy of coarse-grained amalgamated channelized turbidites that evolve downstream into erosional channels, then finer-grained slope depositional channels and elongated sand tongues.
In this framework, the geometrical and geostatistical characteristics of the constitutive architectural elements have been quantified. 3D geocellular reservoir models of the outcrops have been reconstructed and used for synthetic seismic modeling.