Stratigraphic and Spatial
Changes in Channel Morphology Related to Deepwater Processes in Confined and Ponded Slope Mini-Basins,
Clark, Julian D.1, Tim R.
McHargue1 (1) Chevron Energy Technology Company,
Near surface seismic data from offshore
Detailed stratigraphic
interpretation and quantification of channel parameters show the interpreted
interplay between auto- and allo-cyclic processes
involved in filling such confined basins.
Sediment, supplied through deeply incisional conduits, infills the
local accommodation space of each mini-basin through distributary
processes. As flows reach the spill point, high sinuosity migrating channels
develop due to sediment bypass across the low gradients of the ponded fill deposits. When flows breach the spill point,
the depocenter shifts to the downdip
basin, lowering the depositional equilibrium profile, resulting in channel
incision though the spill point and updip erosion of
previously deposited sands.
In the terminal basin a dendritic channel distributary
system develops, with an intricate channel branching network and spatial
changes in channel parameters. The channelized
portions of this distributary network are interpreted
to represent largely auto-cyclic processes by which sediment is distributed
within this confined basin. Stratigraphic changes in
channel density are interpreted to represent largely allo-cyclic
controls on sedimentation.
Quantitative relationships between
channel pattern and sediment processes resolved in this high-resolution dataset
can be used to infer depositional processes, and in particular predict
reservoir quality, in lower-resolution seismic data.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California