Abstract: 3D Process Modeling of Fluvial and Wave Dominated Shorelines for Siliciclastic and Carbonate Sediments

Didier Granjeon, Philippe Joseph, Francois Guillocheau, Jean-Christophe Navarre

Sedimentary units deposited in shallow marine or coastal environments are simulated by a 3D process-based model applied on 4 lithologies: sand, shale, reef and pelagic carbonates. The siliciclastic sediments are introduced in the basin both by fluvial and by longshore transport, and the carbonate lithologies are produced in the basin according to a law dependent on bathymetry and siliciclastic supplies. This 3D model is built on two principles of sediment transport:

1. fluvial activity is described by a diffusive equation both in continental and in marine environments. The variability in time and space of the diffusivity coefficient according to physical parameters (bathymetry, lithology, ...) allows the model to simulate incised valleys, broad flood plains and fluvial-dominated deltas.

2. wave activity is described by an advective equation which simulates the onshore-offshore transport of sediment in the marine environment and the longshore transport in the wave breaker zone.

An inverse method has been developed to determine the main parameters of this model (eustasy, subsidence, sediment supply) from well logs and seismic profiles. The model has been applied in two case studies:

1. a wave dominated shoreline in a foreland basin at a reservoir scale (total duration around 500 ky, and dimension of the reservoir around 10 × 15 km²);

2. a fluvial dominated shoreline in an intracratonic basin (total duration around 10 My, and dimension of the basin around 200 × 250 km²).

The simulations have been calibrated to field data by using the inverse method.

AAPG Search and Discovery Article #90956©1995 AAPG International Convention and Exposition Meeting, Nice, France