Gannet A

Gannet A Oil and Gas Field Profile

The Gannet A oil and gas field is located in the Central North Sea, approximately 180 km (110 miles) east of Aberdeen, UK. It is situated in blocks 21/25, 21/30, 22/21, and 22/26a, at a water depth of about 95 meters (313 feet).

The field is operated by Shell UK Ltd, with Shell and Esso (now ExxonMobil) initially holding a 50% stake each. However, ownership has undergone changes; as of recent updates, the field is owned by Neo Energy Group and Shell.

The Gannet field was discovered in 1973. The original project development was approved by the UK Government in 1989, and production started in November 1993. Over the years, several satellite fields (Gannet B to G) have been tied into the Gannet A facilities.

Gannet A is a four-legged lifted steel jacket offshore drilling, production, and accommodation platform. It serves as the host platform for the subsea satellite tie-backs from fields Gannet B to G.
The reservoir at Gannet A lies at a depth between 1,768 meters and 2,728 meters and consists of good-quality turbiditic sands of Tertiary age (Tay, Rogaland, Forties, Lista, and Andrew Formations).
The field has an oil rim with a gas cap, containing approximately 68 million barrels of oil and condensate, along with 411 billion cubic feet of gas. It has 11 production wells.

The platform has a production capacity of 56,000 barrels of oil per day and 4.0 million standard cubic meters of gas per day. It features four production trains for both oil and gas processing. Electricity generation is powered by two 21-megawatt Rolls-Royce RB211 gas turbines.
Oil is exported through an infield pipeline to the Fulmar platform, while gas is exported through the Fulmar Gas Pipeline to the SEGAL St Fergus Gas Processing Terminal.
The platform has a gas lift capacity of 130 million standard cubic feet per day and a produced water handling capability of 60,000 barrels per day. There is also significant ullage in the system for additional third-party processing and transportation.

Gannet B: A gas field located 5 km northwest of Gannet A, with two subsea wells producing via individual pipelines. It contains 3 million barrels of oil and 139 billion cubic feet of gas.
Gannet C: Located 5 km southwest of Gannet A, it has a thin oil rim and a gas cap. It requires six horizontal oil wells and two gas wells, serviced by 100mm pipelines. It contains 60 million barrels of oil and 140 billion cubic feet of gas.
Gannet D: An oil field 16 km northeast of Gannet A, with five wells producing oil transported through a subsea manifold and two 150mm pipelines. It has 31 million barrels of oil and 30 billion cubic feet of gas.
Gannet E: Located 14 km from Gannet A, it contains 23 million barrels of heavy crude. Production was resumed in 2018 after a pipeline leak in 2011. It is now fully owned by Tailwind Energy and tied into the Triton FPSO.
Gannet F: Lies 11 km from Gannet A, containing 19 million barrels of lighter oil. The field life is approximately 14 years.
Gannet G: Has recoverable reserves of 13 million oil equivalent barrels, producing at an initial rate of 7,500 barrels of oil per day through two new wells tied into the Gannet platform.

The topsides for Gannet A were designed by Matthew Hall Engineering, with fabrication and construction assistance from Redpath Offshore North and RGC Offshore. Technip has been involved in several projects, including the Gannet F reinstatement project.

In 2011, Shell reported a leak from the Gannet Alpha platform, which led to temporary production halts. The field has since undergone various maintenance and redevelopment projects to ensure safe and efficient production.

As of the latest updates, the Gannet A field has recovered approximately 85.92% of its total recoverable reserves, with production expected to continue until the field reaches its economic limit in 2050.
Ongoing and future projects, such as the expansion at Gannet E by Tailwind Energy, indicate continued activity in the area to maximize oil and gas recovery.