Depositional Modeling of Detrital Rocks: With Emphasis on Cored Sequences of Petroleum Reservoirs

Studies of cores from both field and wildcat wells offer the opportunity to interpret subsurface rock sequences and relate them to surface sections, to calibrate mechanical logs with observed lithologies, and to use these data to enhance both field development drilling and wildcat exploration. The cored sequences of detrital rocks described in this core workshop are organized on the basis of depositional models, and presented sequentially down the depositional system through the continental environments to the shoreline zone, and, finally, to the shallow offshore and deeper water environments. Each of the depositional models is treated in separate sections in which diagrams, facies descriptions and terminology are presented that summarize the principal aspects of the model.
Submarine Fan and Fan Channel Environments Available to Purchase
-
Published:January 01, 1985
Abstract
Deposition of submarine fans may occur in a variety of shelf, slope and basin settings (Fig. 8.1), and in association with both high-stand and low-stand sea level conditions. Fan deposition is by a variety of mass flow and traction transport processes (Middleton and Hampton, 1976). Fan deposits accumulate where high volumes of terrigenous sediment are funneled onto the sea floor. The high sediment flux causes mass flow processes to dominate the sediment transport, and the sediments are considered "resedimented" because they have earlier depositional history. Principal mass flow processes are slump and creep, slurry flow, grain flow, fluxoturbidity current, turbidity current, and fluidized flow (Howell and Normark, 1982). While a given bedform or sequence reflects the transport process operating at the time of deposition, the same sediment probably was involved in several mass transport processes on the route from source to final location on the fan.
No sedimentary structures, features or lithofacies are restricted only to the submarine fan or fan channel setting; nearly all the structures, for instance, are recognized also in alluvial fluvial settings. Thus, examination of a single outcrop or core may be insufficient to establish a submarine fan or fan channel setting. Nonetheless, ancient fans and channels can generally be recognized by a characteristic assemblage of structures and lithofacies viewed in vertical and lateral association.