Important hydrocarbon discoveries have been made in submarine fan facies of Devonian to Tertiary age. A large number of controls on fan development include the nature of the sediment source and supply systems, tectonic style and activity, sea-level variation, oceanic conditions, and internal fan geometry. Several fan models have been proposed; the four best-documented models are outlined and then compared with North Sea fans.

Upper Jurassic objectives are important in the North Sea and include both nearshore sandstone and submarine-fan reservoirs. The submarine fans commonly developed close to the active fault-controlled margins of small basins and overlapped laterally to form a base-of-slope sediment apron. Jurassic intervals of the Brae field are believed to be of this type.

Detailed core, electric log, dipmeter, and seismic data from the Brae field have been examined. Conglomerates and poorly sorted sandstones and mudstones are arranged in fining-upward cycles and megacycles and appear to have been deposited by gravity-flow mechanisms in a marine environment. There is no evidence of a single feeder canyon or radial-channel pattern. The Jurassic fan of the Brae field differs in certain respects from the classic fan models but is closely analogous to Upper Jurassic shallow-water fans from east Greenland.

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