A number of carbon steel bottom column pipes, due to be finalised on an offshore platform, in the Forties oil field, 110 miles east of Aberdeen, required protection against corrosion.
The 13 x 3050mm 10″ NB bottom column pipes were abrasive blasted to Sa2½ to achieve the required cleanliness standard, using the Agmec internal pipe blaster to fully remove an existing failed coating. The pipes were then subjected to pressure tests at 29 bar for 15 minutes and then re-blasted and cleaned down and vacuumed.
Polyglass VEF (which has good resistance to seawater as well as many chemicals and solvents) was then applied using specialist internal pipe spraying equipment to a DFT of 1500μm.
In order to provide all round protection the external surfaces of the pipes were coated qwith Plasmet ZF, a surface tolerant coating, before final coat of Corrothane AP1 was applied. After curing the pipes were thickness and spark tested to identify any holidays and ensure the professional quality of the coating work.
Lining the column pipes, both internally and externally with specialist protective coatings will increase the expected service life significantly.
