In the East Shetland Basin oil generation began 65 Ma ago; peak oil generation maturity occurs today at 3,250 m (0.7 percent R₀) and was first reached 40 to 50 Ma ago; the oil generation threshold is at 2,500 m. Highest oil saturations in the Kimmeridge Clay occur at 0.8 percent R₀; oil expulsion efficiencies are >20 to 30 percent. Oil phase migration has probably occurred through oil wet kerogen laminae, and through interconnected large pores aided by low oil/water interfacial tensions. Oil migrated along strong lateral fluid pressure gradients, from overpressured source rocks in half grabens to Jurassic reservoirs in tilted fault blocks.

In the Viking Graben the Kimmeridge Clay is at oil floor maturity below 4,500 m; oil and peak oil generation began 70 to 80 and 55 to 65 Ma ago respectively; 40 Ma ago the Kimmeridge Clay passed through peak generation, and gas generation by cracking of oil had begun. Peak dry gas generation from Brent coals occurs today below 5,000 m, and began 40 Ma ago. The Frigg Field gas, probably generated from late Jurassic source rocks, migrated through microfractures in overpressured mudstones below 3,500 m; above 3,500 m methane probably migrated in aqueous solution and was exsolved in the early Tertiary aquifer.