Abstract: Frigg Field--Large Submarine-Fan Trap in Lower Eocene Sandstones of North Sea Viking Graben

F. E. Heritier, P. Lossel, E. Wathne

Located in the deepest, axial part of the Viking subbasin of the North Sea, the Frigg field, one of the world's largest offshore gas fields, straddles the border of the British and Norwegian continental shelf at lat. 60°N.

The discovery well was drilled in 1971 on the Norwegian block 25/1 in 100 m of water. Gas occurs at a depth of 1,850 m in a sandstone reservoir of early Eocene age (Ypresian) which is a large lobate submarine fan representing the ultimate phase of a Paleocene deposit 1,000 m thick.

Sealed by middle Eocene open-marine shales, the structure is mainly submarine-fan depositional topography enhanced by draping and sandstone-shale differential compaction.

The closed area underlined by a typical "flat spot" on seismic sections is 175 sq km and the 140-m gross gas column lies on a heavy-oil disk 10 m thick. Chromatographic analysis shows that both oil and gas could be coming from underlying Jurassic source rocks.

Production started September 15, 1977; the gas is brought ashore at St. Fergus in Scotland by a 360-km pipeline.

AAPG Search and Discovery Article #90961©1978 AAPG Annual Convention and Exhibition, Oklahoma City, Oklahoma