On the basis of the third appraisal well, Britain’s Core Laboratories had concluded that Ekofisk contained 4 200-6 900 billion barrels of oil.
Of this, 15-22 per cent was considered to be commercially recoverable, with a daily oil production from each well of 8 000-10 000 barrels.
Seismic surveys indicated a number of promising geological structures near Ekofisk. Neptune 7 started drilling an exploration well on the West Ekofisk structure in August 1970, while Ocean Viking simultaneously began work in block 2/7 on Eldfisk.
In addition, the Phillips group participated in the Amoco/Noco group’s first wildcat on a structure which lay on the boundary between blocks 2/5 and 2/4 and had been dubbed Tor. Discoveries were eventually made in all these blocks.
Where does the Ekofisk name come from?Landing options