Exploration and production of oil and gas from deepwater turbidite systems is of high interest to most companies. Several models have been developed, emphasizing the architecture and several aspects of reservoir characterization. Application of a non-suitable model can result in dry holes, bypassed oil, and other frustrations. Of all general models available the most important ones are the coarse-grained and the fine-grained turbidite systems.

The coarse-grained systems are canyon-fed prograding fans that gradually become thinner and finer in the down-dip direction. The fine-grained systems are delta-fed bypassing fan types with well developed leveed channels and significant depositional lobes or sheet sands on the outer/lower fan. Calculations on the Mississippi Fan and Tanqua Karoo fans in South Africa indicate that 75% or more of all the sand in he-grained fans is stored in the sheet sands. Just to indicate that coarse-grained turbidite systems are related to active margins and fine-grained ones to passive margins is only partially correct. The terms active and passive margins should not be used to identify turbidite system types.

A general understanding of the types of transport and depositional processes responsible for the distribution and characteristics of the sands and shales is essential. The factors (tectonics, climate, sediment, relative sea level fluctuations) that influence basin setting, transport, deposition and timing interact rather variably with one and another.

The coarse-grained turbidite systems are rather well understood because those deposits are common in outcrop, often adjacent to productive fields. Fine-grained turbidite systems commonly do not outcrop. That makes it very difficult to determine architectural changes in downdip and lateral direction, as well as reservoir continuity. The non-tilted Permian Tanqua Karoo fan systems in South Africa are the only ones known to make it possible to conduct such observations.

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