Today’s subsea oil and gas pipelines demand corrosion resistant materials due to the highly corrosive substances they carry everyday. Because of this, corrosion resistant alloy (CRA) pipes (including 316L, 904L, 825 or 625) metallurgically bonded clad pipes and mechanically lined pipes have been developed and regularly used in the offshore and subsea industries.
Currently, subsea pipeline installation firms have been paying attention to how to manufacture, handle and install mechanically lined pipe by reel-lay, a method which would speed up installation times, as well as reduce materials costs. Installation by reel lay also enables contractors to lay longer sections of pipe, without having to weld large numbers of stands while offshore. Mechanically lined pipe uses a combination of carbon steel outer pipe with a corrosion resistant alloy liner.
The German pipe manufacturer BUTTING produces BuBi-Pipe, its own-brand mechanically lined pipe, which is telescopically aligned inside a pipe in carbon-manganese material and the tight mechanical bond between the pipes is achieved in a hydroforming facility.
Subsea 7 was the first to install mechanically lined pipe by reel-lay on Petrobras’ pre-salt Guará-Lula NE project in Brazil’s Santos Basin, using the Seven Oceans pipelay vessel. Some 70km of BuBi-Pipe SCRs were installed by reel-lay in 2100m water depth. Subsea 7 is already also lining up its next job, on Statoil’s Aasta Hansteen development offshore Norway for which BUTTING has already delivered the BuBi-Pipe. For the development in the Norwegian Sea about 19km of 12in BuBi-Pipe will be installed by reel-lay.