A 3-D Model for Deep-Water Reservoirs Coupling a Depth Averaged Theory for Turbidity Currents Flowing in Meandering Channels and Vertical Channel Trajectories

Frascati, Alessandro ¹; Bolla Pittaluga, Michele ¹; Sylvester, Zoltan ²; Cantelli, Alessandro ²; Pirmez, Carlos ²
(1)DICAT, University of Genova, Genova, Italy. (2) Shell International Exploration and production, Houston, TX.

Integration between disciplines is often translated in the combination of the tools that different subjects use in order to achieve results. Here the result is an innovative approach to implement reservoir static modeling that involves Geology, Engineering and Physics.

Submarine channels are important hydrocarbon reservoirs in many parts of the world and are counterpart of fluvial channels in deep-water environment. They are spectacular features that can extend for thousands of kilometers across the seafloor and represent the major transport pathways for sediments to the deep see. Canyons incise the shelf and the continental slope and typically present a straight configuration. Proceeding downstream submarine channels are predominantly meandering and sometimes show very regular sinusoidal patterns.

Detail studies of flows within these environments are very rare since turbidity currents are typically destructive and unfrequent. Knowledge of the flow and sediment structure within a turbidity currents comes mainly from theoretical investigations and experimental observations. Flows are also inferred from understanding their deposits through seismic images.

Apart from a larger width/wavelength ratio, the planform morphology of sinuous submarine channels is indistinguishable from that of rivers. Here we wish to extend a depth averaged model for river meandering to the submarine environment. As a first step the analysis is performed assuming a conservative turbidity current flowing under steady condition in a constant width channel. In this respect the crucial point of the analysis is represented by a consistent closure for velocity and concentration profiles on the vertical. This is still a challenging issue especially for the description of secondary flows in curved channels, somehow demonstrated by the ongoing debate struggling the scientific community (Corney et al., 2006; Imran et al., 2007).

In order to build a three dimensional architecture that is similar to those observed in seismic data we couple the meandering model with an independently defined vertical channelform trajectory (Sylvester et al., 2010) which determines how much incision or aggradation occurs at each time step. We model surface evolution geometrically using characteristic cross-sectional shapes so that realistic channel-levee morphology exists at all times.

AAPG Search and Discovery Article #90135©2011 AAPG International Conference and Exhibition, Milan, Italy, 23-26 October 2011.