Overview
AISUS was engaged to undertake a combined cleaning and Ultrasonic Testing (UT) Inspection on a Norwegian offshore platform jacket leg.
The external scope included cleaning, visual and UT inspections through the splash zone, on two 2 metre width sections of the jacket leg. Time of Flight Diffraction (ToFD) inspection was also carried out on a circumferential weld, providing the client with a comprehensive assessment of the asset’s condition.
Requirement
The client required the cleaning and external inspection of two 2-metre-wide, 10-metre-long sections of a 5.25m diameter jacket leg through the splash zone, alongside a ToFD inspection of a circumferential weld. The project combined multiple inspection disciplines into a single deployment to minimise offshore intervention and maximise efficiency.
Challenges
The jacket leg was 5.25m in diameter which is larger than any other pipework AISUS have cleaned and inspected before so it would require customs made tooling. The inspection area was through the splash zone which is generally the most volatile area. The inspection tool needed to be deployed and installed by a rope access team before being lowered through the splash zone on an air hoist.
Solution
AISUS’ R&D team adapted the Auriga inspection system to suit the larger jacket leg diameter and engineered a bespoke sliding frame to support deployment. A custom-designed jetting spray bar was also manufactured specifically for the project.
Prior to mobilisation, the modified equipment underwent testing at the AISUS facility to verify performance and ensure offshore readiness.
Using the customised Auriga system, AISUS successfully:
- Cleaned two 2m-wide sections of the jacket leg to inspection standard.
- Performed a detailed visual inspection of the cleaned areas.
- Conducted remote UT inspection through the splash zone.
- Completed ToFD inspection of the circumferential weld.
Results
- The bespoke cleaning solution effectively removed marine growth and surface contamination, providing a suitable surface for inspection activities.
- Visual and UT inspections identified no areas of wall loss or other anomalies within the inspected sections.
- The ToFD inspection further confirmed the absence of cracking within the circumferential weld.
Benefits
By combining multiple inspection scopes into a single offshore deployment, AISUS delivered a safe, efficient and cost-effective solution, providing the client with confidence that the jacket leg remained in good structural condition and fit for continued service.
