Subsea 7 puts its polymer liner system to use at Senegal’s first offshore oil development

Subsea 7 has completed the polymer lining scope at Woodside Energy’s Sangomar field development Phase 1 project, Senegal’s first offshore oil development. This is said to mark the first use of the Swagelining polymer liner system offshore West Africa and for Woodside Energy.

The Swagelining system was selected as a corrosion barrier for 24 kilometers of water injection flowlines installed at the Sangomar field in water depths of up to 1,300 meters.

Subsea 7’s all-polymer LinerBridge connector was also used to ensure the offshore tie-ins for inline structures were completed with optimal efficiency.

“As well as providing a proven corrosion mitigation solution, the technology provides greater pipeline service life assurance, execution cost effectiveness, and consistent flow performance throughout the pipeline lifecycle,” said Allan Feeney, Product Director, Internal Corrosion Management – Pipeline Products, at Subsea 7.

“It also provides an opportunity to reduce operating expenditure (OpEx) over the life of the pipeline system. For these reasons, the Swagelining polymer lining system is now the default solution for many clients’ water injection pipelines and risers.”

The Sangomar field is located about 100 kilometers south of Dakar and is spread over 400 km2 in water depths of up to 1,400 meters.

Subsea 7 won the contract for the first phase of the project at the beginning of 2020 in a partnership with OneSubsea. The work scope covers the engineering, procurement, construction, transportation and installation of the SURF system and associated subsea production systems (SPS).

Phase 1, targeting approximately 230 million barrels of crude oil, will be Senegal’s first offshore oil project after it comes on stream. First oil is expected in mid-2024.

The project will consist of a stand-alone FPSO, named Leopold Sédar Senghor, with a production capacity of approximately 100,000 barrels per day, 23 subsea wells, and supporting subsea infrastructure.

Woodside is the operator with an 82% participating interest in the project, while its parent Petrosen holds the remaining 18%.

Last month, Diamond Offshore Drilling confirmed that its Ocean BlackHawk drillship had wrapped up its drilling assignment at the oil development and that another drillship would take over.