The Evelyn oil and gas field development project is located in the central North Sea, UK. Image courtesy of Tailwind Energy.
The Evelyn field is being developed as a subsea tieback to the nearby Triton FPSO. Image courtesy of Dana Petroleum.
Stena Drilling was contracted to drill a production well in the Evelyn field. Image courtesy of kees torn.

The Evelyn oil and gas field being developed as a subsea tie-back to a nearby floating production, storage, and offloading vessel (FPSO) in the central North Sea, UK is expected to start operations in the fourth quarter of 2022. Tailwind Energy is the operator and holds a 100% interest in the field.

The Evelyn field development plan was approved by the UK Oil and Gas Authority (OGA) in February 2021 and the final investment decision (FID) on the project was also reached by Tailwind Energy in the first quarter of 2021.

Tailwind Energy became the 100% owner and operator of the Evelyn field through the acquisition of interests in the Triton Cluster from Shell UK, Shell EP Offshore Ventures and Esso Exploration, and Production UK in September 2018.

Location and reservoir details

The Evelyn field is located in block 21/30f, license P1792, in the central North Sea, approximately 190km east of Aberdeen, Scotland, UK. The water depth in the field area is approximately 95m.

The offshore oil and gas field was discovered in 1984 and was subsequently appraised in 1990. The field’s reservoirs comprise the Tay formation channel/lobe sands of the Tertiary age.

Field development plan

The initial field development involves the drilling of a horizontal production well and the installation of associated subsea infrastructure. The well will be tied back to the Triton floating production, storage, and offloading (FPSO) vessel.

A 7km-long, 8in-diameter subsea production pipeline will be laid from the Evelyn field to the new Gannet E, Evelyn, and Belinda (GEEB) manifold. A 7km-long, 3in-diameter subsea gas lift pipeline will be constructed from the GEEB manifold to the Evelyn field. A new umbilical will also be installed from the Triton FPSO to the Evelyn field.

The first Evelyn well is scheduled for drilling in the second half of 2021, while the subsea tieback to the FPSO is expected to be completed in 2022.

Shuttle tankers will transport the crude output from the FPSO to the shore, while the gas output of the Evelyn field will be primarily utilised to power the Triton FPSO and for gas lift operations. The remaining gas will be pumped through a subsea pipeline to the Fulmar pipeline for transport to the St Fergus gas terminal in Scotland, UK.

Triton FPSO

The Triton FPSO, operated by Dana Petroleum since October 2012, is located approximately 6km northeast of the Evelyn field. Dana Petroleum holds a 52% interest in the FPSO, while the other partners are Tailwind Energy (46.4%), and Waldorf Production (1.6%).

The various fields tied back to the Triton FPSO, which started operations in 2000, include the Bittern, Guillemot West, and the Gannet E fields.

The Triton FPSO has an oil processing capacity of approximately 105,000 barrels per day (bpd), a gas processing capacity of approximately 140 million cubic feet a day (mcfd), and a storage capacity of 630,000 barrels of oil.

The FPSO has spare processing capacity to handle the well stream from the Evelyn field.

Contracts awarded

Petrofac was awarded a five-year, well-operator services contract for the Evelyn, Gannet E, and the Belinda license areas by Tailwind Energy in September 2018.

Stena Drilling was contracted Petrofac to drill a production well in the Evelyn field in January 2021. Stena Drilling’s semisubmersible rig Stena Don will be deployed to execute the drilling operations in July 2021.

Technip UK, a subsidiary of TechnipFMC, was awarded the subsea engineering, procurement, installation, and commissioning (EPIC) contract for the combined Evelyn field and Gannet E expansion project. Dana Petroleum is responsible for the subsea scope of the project.