First Oil from the Mariner Field in the UK North Sea

Equinor and partners announced first oil from the Mariner field in the UK North Sea. The field is expected to produce more than 300 million barrels of oil over the next 30 years.

“The start-up of Mariner, the first Equinor-operated oil field on the UKCS, establishes our foothold in the UK and reinforces our commitment to be a long-term energy partner,” says Hedda Felin, senior vice president for UK and Ireland Offshore in Equinor.

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.

“By gathering and interpreting new seismic data we have improved our understanding of the reservoirs. This has resulted in fewer and better placed wells and increased resources since the project was sanctioned in 2012. With the significant volumes in place, we see clear potential to further increase the oil recovery from the Mariner field and will proactively seek opportunities to do so through the application of new technology, additional drilling and future tie back opportunities,” says Anders Opedal, executive vice president for Technology, Projects and Drilling in Equinor.

Mariner is one of the largest industrial projects in the UK in recent years. A gross investment of more than USD 7.7 billion, the development will support more than 700 long term jobs and generate significant revenue in the supply chain for decades to come. Contracts worth more than USD 1.3 billion have been awarded to UK suppliers since the project started.

“With the start-up of Mariner, we have delivered one of the most complex developments in the North Sea and Equinor’s portfolio. We will continue to apply digital solutions and new technology to deliver safe and efficient operations and optimize production,” adds Anders Opedal.

Digital solutions include automated drilling, digital twin, field worker tools, and digitized logistics to support operational and field maintenance planning.

In the UK, Equinor has established a broad energy portfolio including oil, gas and offshore wind, with Mariner as the foundation of its upstream operations.

“Many have played a part in bringing Mariner onstream safely including our partners, contractors and suppliers, and we are grateful for their important contributions,” Hedda Felin mentions.

“Mariner is one of our most innovative offshore developments, and Equinor is at the forefront of applying new digital solutions and the latest technologies. We are testing new ground through our offshore digital workers, automated drilling and the use of Echo, a digital copy of the platform, to deliver safe and efficient solutions,” Equinor representatives point out.

The Mariner field will contribute towards reliable energy supplies for the next 30 years and, with up to 3 billion barrels of oil in place, offers significant potential to create even more value to 2050 and beyond.

Discovered in 1981, the Mariner field was left untouched due to the complexity of the reservoir. In 2007, Equinor acquired the operatorship, and through new ways of thinking and new technology, the company started to find ways to meet the challenges laid down by this demanding field.

The Mariner field is located on the East Shetland Platform in UK Block 9/11a in the northern North Sea approximately 150 kilometres east of the Shetland Islands. The field development concept includes the Mariner A production, drilling and living quarters (PDQ) platform based on a steel jacket with a floating storage unit (FSU), Mariner B. Drilling will be carried out from the PDQ drilling rig together with a jack-up rig assisting during the initial phase.

The Mariner oil field consists of two shallow reservoir sections: the deeper, Maureen formation and the shallower Heimdal reservoir.


Mariner field

Maureen formation:

  • 1492 meters
  • API gravity: 14.2
  • Viscosity: 67 cP

Heimdal reservoir:

  • 1227 meters
  • API gravity: 12.1
  • Viscosity: 508 cP


Mariner facts

  • Equinor is the operator of Mariner with 65.11% equity. The partners are JX Nippon (20%), Siccar Point (8.89%) and ONE-Dyas (6%).
  • Digital frontrunner in the North Sea applying new technology to deliver safe and efficient solutions
  • Production start August 2019
  • Contracts worth more than USD 1.3 billion awarded
  • Recoverable reserves increased from 250 to 300 million barrels of oil
  • Up to 3 billion barrels of oil in place offering significant upside for the development in the future
  • Long-term UK field development to 2050
  • Located on the East Shetland Platform of the UK North Sea, approximately 95 miles or 150 kilometres east of Shetland and 320 kilometres north-east of Aberdeen

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