Petroleum systems of the Atlantic margin of northwest Europe

Abstract

The Atlantic margin region of northwest Europe includes, on its inboard side, five basins which have been explored since the 1970s and contain proven, Jurassic-sourced petroleum systems: Halten Terrace, the Northern North Sea, the Faeroe-Shetland Basin, the Slyne-Erris troughs and Porcupine Basin. The hydrocarbons in most of these basins are in Jurassic sandstone reservoirs within late Jurassic fault traps. To the northwest, on the outboard side of the Atlantic margin, lie four frontier areas in which exploration is mostly only just beginning: the Vøring, Møre and Rockall basins and the Faeroes Shelf. The basins often have Cretaceous strata which are many kilometres thick, whilst Tertiary strata are thick in some places but thin (starved) in others. Cretaceous and Tertiary extensional faulting phases created fault traps in some parts of the basins and mid Tertiary compressional domes provide important traps elsewhere. The least known aspect of the petroleum geology of these basins is the presence and maturity history of any source rocks. The outboard basins are bordered to the northwest by a zone of Paleocene-Eocene volcanic rocks, which are over 5 km thick at the Faeroe Islands. The lava sheets were dominantly subaerial and may conceal eroded but prospective Paleocene and Mesozoic strata. The outboard frontier areas may contain extensive petroleum systems. In the Vøring Basin two major discoveries prove the existence of petroleum systems there but both their geographical extent and source are unknown. Petroleum systems may be present in the main Møre Basin, beneath some part of the Faeroes Shelf and along both margins of the Rockall Trough.