Kolla, Ven1, Henry Posamentier2, Mochammad Fachmi3, Lesli
(1) Consultant, Houston, TX
(2) Anadarko Corporation, Calgary, AB
(3) Jackson School of Geosciences, The University of Texas at Austin, Austin, TX
(4) University of Texas at Austin, Austin, TX
ABSTRACT: Modes of Evolution of Deep-water and Fluvial Channels
High-resolution 3D seismic and side-scan sonar images from various stratigraphic intervals and the present seafloor, suggest that meander channels in both fluvial and deep-water environments are similar in a variety of ways: planform sinuosities and their response to changes in valley gradients, relationships between meander wavelength and both channel width and radius of meander curvature, and seismically expressed crescent-shaped high seismic-amplitude fields within the meander loops. However, in deepwater channels, lateral migrations as reflected in crescent-shaped amplitude fields may be either discrete, separated from each other in distance or continuous. In fluvial channels, the migrations are continuous. In cross sections transverse to the meander loops, the tops of the reflections from inner to outer banks that form the crescent amplitude fields may be either flat (horizontal) or more commonly aggrading in deepwater and predominantly flat in fluvial channels. The meander belts are usually one seismic loop thick in the fluvial channels but are significantly thicker in the deep-water channels. The strata in the gross depositional fill within the meander loop present an off- lapping character in the fluvial channels, typically below the seismic resolution, and off-lapping or up-lapping character in the deepwater channels within and below seismic resolution. The similarities suggest that both deep-water and fluvial channels become highly sinuous in attempts to establish equilibrium conditions. The differences, however, show that the precise mode of accomplishing the increased sinuosities are different in deep-water and fluvial channels and result from the hydrodynamic characteristics unique to each environment
AAPG Search and Discovery Article #90026©2004 AAPG Annual Meeting, Dallas, Texas, April 18-21, 2004.