Aqua Milling® of 12” Lyell Riser on Ninian South


Pipetech was approached by KTN AS on behalf of CNRI UK to perform high pressure Aqua Milling cleaning of its 12” Lyell Riser on the Ninian South platform prior to UT inspection.


A specialist Aqua Milling team completed  cleaning from entry point, 320 meters down to a subsea manifold and back. Aqua Milling on deployment and retrieval consisted of a polishing run to prepare the walls for UT inspection. Cleaning at a rate of 1 foot per minute to ensure total effective cleaning of pipe wall internal. All waste / rust deposits were collected via EPAT and fluids pumped to the closed drains system.


  • Successful cleaning and recovery to required distance, 320 meters negotiating 9 bends from entry to SSIV.
  • Workscope completed ahead of scheduled, reduced from 8 to 4 days.
  • UT inspection data deemed acceptable after 2 cleaning runs.
  • All waste fluids fully contained from pipeline to waste disposal through closed drains with no loss of containment and / or environmental impact.


  • Safety – Fully contained remotely operated Aqua Milling system.
  • Flexibility – Work scope carried out utilizing the minimum of deck space as possible.
  • Performance – A skilled and experienced team, providing the excellent customer service and surpassing customer expectations.

Key Project Facts




Product Line

Long Reach Aqua Milling®

Personnel – Day Shift

1 Specialist Cleaning Supervisor

1 Specialist Cleaning Technician

1 Specialist Cleaning Operative

Duration - 48 hours cleaning time





"Great progress, brilliant effort from the Pipetech team."