The Dunlin platform is an offshore oil and gas production platform located in the UK sector of the North Sea, approximately 150 miles north-east of the Shetland Islands. It is operated by Fairfield Energy and is one of the largest platforms currently operating in the North Sea.
Location of the Dunlin Platform
The Dunlin field lies in Block 211/23a of the UK Continental Shelf. The platform is located at the following coordinates:
- Latitude: 61° 10′ N
- Longitude: 1° 45′ E
The platform sits in a water depth of approximately 140 metres. It is located around 24 kilometres south-west of the Brent oilfield complex and 45 kilometres north-east of the Sullum Voe oil terminal on Shetland where Dunlin crude oil is offloaded.
History and Development
The Dunlin field was discovered in 1974 by Shell/Esso with the drilling of exploration well 211/23a-1. Appraisal drilling confirmed a large oil and gas accumulation with estimated recoverable reserves of around 600 million barrels of oil equivalent. Production began in 1978 from the Dunlin Alpha platform which had processing facilities and accommodation for up to 120 personnel.
The Dunlin field later subsea tiebacks to the Dunlin Alpha platform from Dunlin Southwest in 1984 and Dunlin South in 1996. In 2000, the owners decided to replace the aging Dunlin Alpha with a new platform known as Dunlin Alpha North East (DANE).
The DANE platform was installed around 3 kilometres from the old Dunlin A platform. It began production in 2002 and has facilities to process oil and gas from Dunlin, Dunlin SW and Dunlin S. It has living quarters for around 100 people.
Ownership and Operator
The Dunlin field is operated by Fairfield Energy, a North Sea-focused exploration and production company. Fairfield Energy acquired its interest in Dunlin from Marathon Oil in 2016.
The current ownership interests in the Dunlin field are as follows:
Company | Ownership % |
---|---|
Fairfield Energy | 43.25% |
INEOS | 31.56% |
Mitsui | 12.59% |
Eni | 9.60% |
Spirit Energy | 3.00% |
Under the terms of the joint venture agreements, Fairfield Energy is the designated operator of the Dunlin Platform and associated subsea infrastructure. They are responsible for the day-to-day operations, maintenance and further development of the assets.
Facilities and Infrastructure
The main facility offshore is the Dunlin Alpha North East (DANE) platform. This is a 19,000 tonne fixed steel jacket platform in 140 metres of water. It has topsides weighing approximately 13,500 tonnes.
Key facilities and infrastructure on DANE include:
- Oil and gas separation trains
- Seawater injection pumps
- Gas compression
- Utilities and power generation
- Accommodation for up to 100 personnel
- Helideck
There are subsea pipelines that transport oil 14 kilometres from DANE to the Dunlin Storage Vessel (DSV). This is a Floating Production, Storage and Offtake vessel (FPSO) with a storage capacity of 750,000 barrels of oil. It allows for year-round offloading by shuttle tankers.
Gas from DANE is transported 32 kilometres via pipeline to the Thistle Alpha platform for onward transmission to the BP-operated Central Area Transmission System (CATS) pipeline terminal at Teesside.
Current Status and Production
The Dunlin field remains a major North Sea producer. According to Fairfield Energy, the field had an output around 35,000 barrels of oil equivalent per day (boepd) in 2019.
Current production comes from the DANE platform along with three subsea satellite tie-backs:
- Dunlin Southwest
- Dunlin South
- Merlin
Fairfield continues to invest in new projects to extend the field life of Dunlin and neighboring discoveries. This includes development of the Merlin field which came on stream in 2018 and is tied back to Dunlin DANE.
Recent estimates suggest there are still around 90 million barrels of oil equivalent remaining in the Greater Dunlin Area fields. As of 2020, the facilities are expected to continue production until 2027 or beyond.
Decommissioning
When production from Dunlin ceases in the late 2020s, the facilities will need to go through a decommissioning process. This involves cleaning and purging oil and gas from the pipelines and topside facilities.
The main options for the DANE platform jacket are complete removal or partial removal to leave the jacket footings in place on the seafloor. Facilities containing hazardous wastes will also need to be brought onshore for appropriate disposal.
Fairfield Energy and the other joint venture partners are required to submit decommissioning programs and carry out the work in accordance with UK regulations. Costs for decommissioning Dunlin are currently estimated at over £1 billion.
Conclusion
The Dunlin field has been a major flagship asset for the UK North Sea oil and gas industry since production began in 1978. While the original platforms and facilities have been replaced over the last 40+ years, it remains an important source of oil and gas production.
The Dunlin Alpha North East (DANE) platform now processes and exports production from Dunlin and several satellite subsea fields. Operator Fairfield Energy continues to invest in near-field tie-backs and improved oil recovery to extend the producing life of Greater Dunlin Area.
When production does eventually cease, decommissioning of this large offshore complex will be a major undertaking. However, Dunlin has many more years of production ahead before that happens.