Process-Based Stochastic Modeling, from Fluvial to Turbiditic Channelized Meandering Reservoirs

Isabelle Cojan, Jacques Rivoirard, François Geffroy, Simon Lopez, and Olivier Bahabanian
Ecole des Mines de Paris, Fontainebleau, France

A new generation of models, integrating a process-based and stochastic approach, allows providing a better description of reservoirs. The fluvial model gives a comprehensive description of meandering reservoirs. Facies as well as sedimentary bodies and series architecture are accurately represented. Building 3D blocks can be constrained by regional information on facies proportions and preferential location of channelized deposits. The model can be somehow conditioned to data from several wells and seismic lines, honoring facies such as point bar, mud plug, overbank deposits and levee/crevasse splay.

As observed by many authors, the planar morphology of submarine channels looks similar to that of terrestrial rivers, up to a point that it is not possible to distinguish one system from the other from their 2D morphology, although scales are different. However, the sedimentary load is the governing factor of turbidity currents while it plays a minor role in rivers.

Based on these elements, we are developing a model of channelized turbiditic reservoirs that respects: 1) a varying sediment load through time and space,2) a mass balance taking into account migration, erosion, flow stripping and spill over. First results concern the channelized deposits, taking into account the nature of the turbiditic flow (depositional or erosive) and its composition (initial granulometric distribution). Point bars, at the scale of turbiditic systems with alternating muddy and sandy deposits, are successfully modeled.

AAPG Search and Discovery Article #90039©2005 AAPG Calgary, Alberta, June 16-19, 2005