The NE Atlantic margin; implications of late Mesozoic and Cenozoic events for hydrocarbon prospectivity

The study takes in the entire NE Atlantic margin (NEAM) but emphasizes the sparsely drilled More and Voring Basins. A network of Permo-Triassic and Jurassic basins was strongly overprinted by younger extensional episodes. At least three phases are probable--early Cretaceous, mid-Cretaceous and latest Cretaceous-early Eocene--between the late Jurassic and break-up. Substantial thicknesses of Cretaceous and Cenozoic strata along the margin have focused exploration interest on the late Cretaceous and Paleocene intervals as easily drillable targets. Reservoirs within these intervals were deposited as gravity-driven sand incursions into an overwhelmingly mud-prone environment. Sand pulses of Albian-Coniacian, Santonian-early Campanian and Paleocene age occur widely, and can be tied to the tectonic episodes. Vertical migration of hydrocarbons from known Jurassic source rocks is proven west of Shetlands, but in many parts of the margin remigration from intermediate reservoirs would be required to charge the shallower plays. Failing this, prospectivity will hinge on the presence of frontier source rocks, with best possibilities at Barremian, Aptian-Albian, Cenomanian-Turonian and Paleocene levels. Potential hydrocarbon traps were formed by pre-breakup extensional faulting and by post-breakup compression.