Equinor ASA and its partners are considering a tie-in of the Skruis (7220/5-3) exploration well drilled in production license 532 in the Barents Sea to Johan Castberg oil field following confirmation of 12-25 million bbl of recoverable oil.
Skruis was drilled using Songa Offshore’s Songa Enabler semisubmersible drilling rig starting Sept. 27 to a TVD of 1,750 m subsea and was terminated in the Fruholmen formation from the late Triassic Age. The well was drilled in 409 m of water 8 km northwest of the Johan Castberg discovery well 7220/8-1 and 225 km northwest of Hammerfest, Norway.
The primary exploration target was to prove petroleum in reservoir rocks from the Middle Jurassic Age (the Sto and Nordmela formations). The secondary exploration target was to prove petroleum in reservoir rocks from the Early Jurassic Age (the Tubaen formation).
The well encountered a total oil column of about 35 m in the Sto formation, 30 m of which was effective reservoir in sandstone with moderate-to-good reservoir quality. The oil-water contact was encountered at 1,415 m subsea. Both the Sto and the Nordmela formation are a little thicker than expected. The Sto formation has about 30 m of water-bearing sandstone below the oil-water contact, with mainly good reservoir properties. The Nordmela formation has water-bearing sandstone layers totaling more than 100 m with moderate-to-good reservoir quality. In the Tubaen formation, the sandstone layers have moderate-to-good reservoir properties.
The ninth exploration well in the license, Skruis was not formation-tested, but extensive data acquisition and sampling have been carried out. The well will be permanently plugged.
Songa Enabler will now drill five production wells in Trestakk field in the southern part of the Norwegian Sea, where Equinor is the operator.
Skruis is the first operated exploration well drilled by Equinor this year in the Barents Sea. Timing of a potential development of the discovery will be adjusted to Johan Castberg field’s planned start-up in 2022 (OGJ Online, Sept. 10, 2018).
“Through the Johan Castberg field development, we open a new oil province in the Barents Sea, enabling us to tie in this type of small discoveries that will be highly attractive when the infrastructure is in place,” says Knut Gjertsen, project director for the Johan Castberg development.
Recoverable reserves in Johan Castberg are estimated at 450-650 million bbl. The volumes from Skruis and the Kayak discovery from 2017 are not included in this estimate (OGJ Online, July 5, 2017).
Equinor has 50% interest in PL532 alongside Eni SPA 30% and Petoro AS 20%.
