Three-Dimensional Modeling of Arkansas River Sedimentation

LEE YOUNG-HOON, Stanford University, Stanford, CA, NORMAN L. HASKELL and MARK L. BUTLER, Amoco, Tulsa, OK, and JOHN W. HARBAUGH, Stanford University, Stanford, CA

A case study is presented where a fluvial system is modeled in three dimensions and compared to data gathered from a study of the Arkansas River. The data are unique in that they document changes that affected a straight channel excavated within the river by the U.S. Army Corps of Engineers. Historic maps, photographs, and cross-sections show that the channel underwent massive erosion and channel migration as it returned to a more natural, meandering path. These records illustrate that stability of a fluvial system can be disrupted either by catastrophic events such as floods or by subtle events such as the altering of a stream's equilibrium base level or sediment load. SEDSIM, Stanford's Sedimentary Basin Simulation Model, is used to model the Arkansas River and the geologic processe that changed in response to changing hydraulic and geologic parameters resulting from the excavation of the channel. Geologic parameters such as fluid and sediment discharge, velocity, transport capacity, and sediment load are input into the model. These parameters regulate the frequency distribution and sizes of sediment grains that are eroded, transported, and deposited. SEDSIM experiments compare favorably with field data, recreating similar patterns of fluid flow and sedimentation. SEDSIM simulations provide insight for understanding the spatial distribution of sediment bodies in fluvial deposits and the internal sedimentary structure of fluvial reservoirs. SEDSIM can also be used to simulate depositional systems on a regional scale, providing applications to oil and gas exploration where characterization of heterogeneities in reservoirs are important.

AAPG Search and Discovery Article #91004 © 1991 AAPG Annual Convention Dallas, Texas, April 7-10, 1991 (2009)