--> Abstract: Simulation of the Stratigraphic Architecture of the Pab Turbiditic Channels: The Additional Value of a Process-Based Numerical Approach with the CATS Model, by Rémi Eschard, Vanessa Teles, Tristan Salles, and Simon Lopez; #90078 (2008)

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Simulation of the Stratigraphic Architecture of the Pab Turbiditic Channels: The Additional Value of a Process-Based Numerical Approach with the CATS Model

Rémi Eschard, Vanessa Teles, Tristan Salles, and Simon Lopez
Department of Sedimentology, IFP - Institut Français du Pétrole, Rueil-Malmaison, France

The Pab sandstone (Maastrichtian, Pakistan) constitutes an unique example of turbiditic systems outcropping on a 200km-long cross-section, from the margin to the distal lobes. This turbiditic system was studied both at regional and reservoir-scales. The stratigraphic architecture and reservoir heterogeneity were described in different settings: canyon, channel and lobes. From them, 3D gridded reservoir models were build, and seismic and well test simulations were also performed. This outcrop analog to similar producing reservoirs in subsurface was helpful in understanding reservoir geometry and behaviour during production.

Besides, a process-based numerical model for turbidite systems was developed based on cellular automata concepts. Each cellular automaton exchanges matter and energy with its neighbors and evolves trough time according to local rules describing turbulent flow over a given topography, erosion and deposition of several lithologies and entrainment of water by the flow. This CATS (Cellular Automata for Turbidite systems) model is able to simulate different architectural elements such as erosive channels, levees, channel mud-plugs and lobes, and predicts their sand content.

The CATS model was tested on the Pab outcrop dataset. It reproduced the different phases of incision and infill of the turbiditic channels and of the overflow deposits. Of particular interest was the insights on the event chronology of channel and levee deposition. The "external" levees deposition occurs first during an initial phase of channel by-pass. When the flow energy increased, the channel incision also increased and "internal" levees were confined in the channel pathway, forming stepped terraces. Finally, the channel infill could be simulated either as a sand- or a mud-plug, depending on the variation of physical parameters such as flow height, velocity or sediment charge.

 

AAPG Search and Discover Article #90078©2008 AAPG Annual Convention, San Antonio, Texas