3-D process modelling of ancient storm-dominated deposits by an event-based approach: Application to Pleistocene-to-modern Gulf of Lions deposits - Université Pierre et Marie Curie Accéder directement au contenu
Article Dans Une Revue Marine Geology Année : 2013

3-D process modelling of ancient storm-dominated deposits by an event-based approach: Application to Pleistocene-to-modern Gulf of Lions deposits

Résumé

A new numerical model was developed for 3-D characterization of deposits generated by storms along clastic coasts away from major rivers. It is based on the assumption that the preserved sedimentary heterogeneities result mainly from a succession of deposits generated during both fair-weather periods and major events (storms in our case). Hydro-sedimentary processes are first modelled during these major storms: (i) transport parallel and transverse to the coast of suspended sediment by the strongest unidirectional currents (littoral drift and downwelling currents), (ii) sea-bed erosion due to shear stress generated by unidirectional and wave-induced oscillatory currents, (iii) deposition of sediment. Fair-weather deposits are modelled by an average deposition process. The results of the numerical model, i.e. the description of the sedimentary deposits, are multi-lithologic, in three dimensions and with a flexible vertical resolution. The latter is one of the main strengths of the model because the vertical description of the deposits can be adapted to the duration and extent of the simulation in order to save computation time. Very precise results (definition of less than 1 mm) can be obtained at a small time-scale (for storms lasting several hours to several days), and reservoir-scale results at a longer time scale. The numerical model was applied to the Gulf of Lions, which is located off the southern French coast, in the north-western Mediterranean. First, present-day storm deposits are simulated in order to validate the storm-process modelling. Then sedimentary deposits formed over several thousands of years, during the Pleistocene, are simulated in order to validate the sediment-deposit modelling. The model results fit well with observations and validate the approach of simulating the shelf deposits and their associated sedimentary heterogeneities at reservoir scale with an event- and process-based method. This innovative approach seems promising for providing future geological models with realistic petrophysical properties. (C) 2012 Elsevier B.V. All rights reserved.

Dates et versions

hal-01196252 , version 1 (09-09-2015)

Identifiants

Citer

L. Laigle, Pierre Joseph, G. De Marsily, S. Violette. 3-D process modelling of ancient storm-dominated deposits by an event-based approach: Application to Pleistocene-to-modern Gulf of Lions deposits. Marine Geology, 2013, 335, pp.177-199. ⟨10.1016/j.margeo.2012.11.007⟩. ⟨hal-01196252⟩
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