A Process-Based Cellular Automata Model for Turbiditic Reservoirs (CATS) Applied to Complex Turbiditic Systems

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

The CATS (Cellular Automata for Turbidite Systems) model has been developed for the simulation of turbiditic currents and their associated deposits along the flow path. This process-based numerical model has been developed based on cellular automata concepts. The computational space is divided into a regular mesh. Each cell is an automaton whose attributes describe the local physical characteristics of the bed and of the flow: elevation, flow height, velocity and bed sedimentary proportions and flow sedimentary composition. Each automaton exchanges matter and energy with its neighbors through local interactions. Its energetic and physical states evolve trough time according to internal transformations. Local interactions and internal transformations are the local elementary expression of the chosen modelled physical processes: turbulent flow over a given topography, subsequent erosion of the bed, deposition of several lithologies and entrainment of water by the flow. The CATS model simulates through time the full three dimensional stratigraphic architecture of turbiditic channels, levees, mud-plugs and lobes and their facies partitioning and sediment sorting.

The CATS model provides reservoir geologists with an efficient physically-based tool to investigate quantitatively the geometry, architecture and facies distribution of complex turbiditic systems. It is applied both to outcrop analogs such as the Pab sandstone formation (Maastrichtian, Pakistan) which exhibits a succession of channels and lobes outcropping on a 20 000 km² area and to subsurface datasets. The CATS model gives new insights on the event succession of the Pab reservoir construction and in particular, on the deposition chronology of channels and lobes in such complex settings.

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