Computer Modeling of Subaerial and Subaquirous Meandering Channels

Sun, Tao¹, Gary Parker², Kaveh Ghayour¹, Robert Wellner³ (1) ExxonMobil Upstream Research Company, Houston, TX (2) University of Illinois, Urbana, (3) ExxonMobil Upstream Research Company, Houston 77252-2189, TX

Subaerial and subaqueous meandering channels and their associated levee deposits are important geomorphologic features that can comprise a substantial portion of the fill within many sedimentary basins. Point bar and sandy splay deposits associated with meandering channels often make excellent reservoirs and are the primary targets in many producing fields. As such, a clear understanding of the rock properties within meandering channels is critical for exploiting these reservoirs in the subsurface.

Current numerical models use similar perturbation techniques to obtain local flow variations within channels. These models assume that the channel is at or near equilibrium, meandering across a uniformly inclined plane of infinite length. These assumptions greatly limit the applicability of the model results, especially in the basin filling scenarios. Because they could not account for sediment supply, tectonics and sea level variations, and other large-scale forcing mechanisms.

A new and substantially improved model for meandering channels has been developed. In our model, cross section averaged fluid flow and sediment transport is first calculated numerically along the channel. The numerical solutions are then used as base solutions. Cross channel variations of flow and sediment transport are then obtained by perturbing the base solutions. Furthermore, in this formulation, both upstream and down stream boundary conditions (i.e. flow discharge, sediment supply, base level fluctuations), as well as regional forcing mechanisms (tectonics) can be applied and subsequently, their effect on the meandering channel dynamics and development of strata architectures can be evaluated.