Equinor has closed the sale of a 40.81% equity interest in the Bressay oil field in the northern North Sea to UK-based petroleum exploration firm EnQuest.

Located 12km north-east of the EnQuest-operated Kraken heavy oil field, the Bressay heavy oil field is said to be one of the largest undeveloped oil fields in the UK Continental Shelf (UKCS).

Following the completion of the deal, EnQuest owns a 40.8125% interest and operatorship in the Bressay project while Equinor has a 40.8125% non-operated interest. The remaining 18.375% interest is held by Chrysaor.

According to the deal signed in July 2020, EnQuest agreed to acquire the stake in the Bressay field for an initial sum of £2.2m ($2.9m).

Upon securing authority approval for a field development plan (FDP), an additional $15m will be paid by the company.

Equinor earlier said that the concept selection for the field development was deferred in 2016 due to challenging market conditions at that time.

Located across four UK licence blocks P234, P493, P920 and P977, the Bressay oil field was discovered east of Shetland in 1976. Equinor became the operator of the field in 2007.

The field has been appraised through the drilling and testing of four further wells with flow rates of up to 2,900 barrels of oil equivalent (bopd).

The Bressay oil field is estimated to have stock-tank oil initially in place (STOIIP) of 600 to 1,050 million barrels (MMbbl).