MODELING SINUOUS SUBMARINE CHANNEL DEPOSITS AIDED BY MODERN SEAFLOOR AND OUTCROP ANALOGS (Invited Presentation)

Building realistic reservoir models of deep-water channelized systems is challenging as a result of incomplete or limited resolution input data and, thus, can benefit from information from other sources. Although outcrops offer high-resolution perspectives, they are inevitably disconnected along a given transect. Extensive 3D seismic data can offer planform perspectives; however they rarely resolve formative, smaller-scale channelized architecture in cross section. High-resolution 3D perspectives of the seafloor provide a unique opportunity to quantify submarine channel morphologies and to derive mathematical relationships between planform expression and cross-sectional geometries, which can be utilized to build models to test the impact of channel architecture on fluid flow and connectivity.

Bathymetric data from the modern Lucia Chica Channel System, offshore California, was analyzed to quantify relationships between channel sinuosity and cross-sectional asymmetry. Cross-sectional asymmetry was quantified and calculated for 9 cross-sections around each channel bend. In total, 30 channel bends were analyzed with 270 cross-sections measured. A bed-scale architectural model was constructed using the sinuosity-asymmetry relationship derived from Lucia Chica, including internal channel architecture, based on statistics derived from outcrop measured sections. While the relationship between the bathymetric cross-sectional asymmetry and stratigraphic channel fill asymmetry is unclear from examined outcrop exposures, a range of hypotheses was tested.

Results show that the surface area connections between channels are significantly reduced at the bend apex of the sinuous-asymmetric channels and most dissimilar from a comparable straight-symmetric channel scenario. Conversely, connections at the inflection of the sinuous channel, where the channels are most symmetric, most closely resemble the connectivity in the straight-symmetric channel scenario. Furthermore, statistics along the length of the channel system reveal that the bend apex is more susceptible to disconnected sandstone beds. Ultimately, this work aims to understand the impact of bed-scale channel architecture on fluid flow, and to take steps toward building more predictive models.