J-Tubes Risers inspections platform leg



No name


North Sea offshore installation


Upstream oil and gas

Associated capabilities


Stork was contracted by a major North Sea operator to inspect four J-Tube risers located within a platform leg. The aim of the inspection was to evaluate the condition of the J-Tubes, in order to facilitate an extended platform life strategy.


The J-Tubes ranged in size from 10” to 14”, and ran vertically within a concrete platform leg (with a series of shallow bends) before penetrating the leg wall, passing through storage cells and finally out to the sea. The portion of the J-Tube passing through the storage cells was not accessible for external NDT, so an internal scanning solution was required. A bespoke Stork inspection vehicle was used for both pipe diameters, and allowed for both camera and ultrasonic (C-Scan) inspection of the J-Tubes. Ultrasonic scanning was carried out on the full length of all four J-Tubes.


Stork’s Specialist Inspection Services team brought a wealth of skills, knowledge and experience to the challenging project. In total, more than 700 meters of corrosion mapping was completed, utilizing a customized crawler tool. Data was received in real-time for immediate feedback, allowing Stork’s experienced engineers to analyze all information promptly. The database and video results produced by Stork allowed the client to establish and facilitate an extended platform life strategy. All Stork Specialist Inspection work is carried out to highest safety standards via utilization of Stork’s safety initiative, REACH.

Project details

Date: 2012

Project team​: Internal Project Management including Project Focal Point and Integrity Engineers

Equipment utilised: A bespoke Stork inspection vehicle J-Tubes: ranging in size from 10” to 14”

Mapping: Over 700m of Ultrasonic Corrosion Mapping data collected and processed 2001-ongoing

Workscope completion: Accomplished under budget and on time

safety: Project delivered safely with no lost time incidents (LTIs)