Norwegian oil and gas company Equinor has exercised the fourth of six one-month options to extend Prosafe’s Safe Boreas flotel at the Mariner project in the UK sector of the North Sea.

Prosafe said on Friday that the unit is being used to accommodate personnel working on Mariner in the hook up and early production phase through October 2019.

Total value of the one-month option is approximately $5 million, Prosafe added.

It is worth reminding that Equinor exercised the third of six one-month options for the Safe Boreas back in April 2019.

Discovered in 1981 on the East Shetland Platform, approximately 150 kilometers east of the Shetland Islands, the Mariner is a heavy oil field characterized by dense, viscous oil. First oil from the Mariner field was achieved earlier this week and the field is expected to produce more than 300 million barrels of oil over the next 30 years.

The Mariner reservoirs have up to 3 billion barrels of oil in place, a 50% increase on what was originally assumed, and the estimated recovery rate has already been increased by 20 percent. Mariner is expected to produce annual average plateau rates of around 55,000 barrels of oil per day and up to 70,000 barrels of oil per day at peak production.