C-Scan 

Subsea 3D laser imaging system

  • Laser triangulation system
  • 2D and 3D representations
  • Range resolution up to 0.5mm
  • Precision distance measurement 
  • 3000m depth rating

C-Scan is an optical 3D scanning system that may be used to generate accurate dimensional measurements from internal and external scans. Target applications include caissons, pipes, piles, flanges, anodes and other subsea structures. The laser triangulation system takes measurements 15 times per second, generating 700 discrete data points per scan, and may be rotated through 360° to build up a complete 3D data point representation. A range of software tools allow data manipulation, visualisation, measurement and export to a CAD package. The system requires a 24VDC input, a video channel and either RS232 or RS485 serial.

 

FPSO anchor chain inspection

The 3D imaging and accurate measurement capabilities of C-Scan can be deployed to inspect the integrity of FPSO anchor chains or other subsea mooring chains. The images below show a studded anchor chain measured in air using a standard electronic vernier caliper, and the same measurement determined underwater by 3D laser scanning.

C-Scan was deployed using two ROV-mounted manipulators. The chain was held with one manipulator and the C-Scan was brought into position with the other. Results presented to the client included the chain link radius at various positions. The scans also reveal pitting corrosion detail on the chain and highlight weak points.

 

Caisson internal inspection

A global oil and gas major requested specialist technical assistance with their North Sea offshore asset integrity program. Having previously suffered a seawater lift caisson failure, a rapid reaction program of inspection and repair was targeted at a second caisson of similar condition. OceanTools were requested to perform a remote visual surface inspection.

C-Scan optical 3D laser scanning technology was deployed into the caisson and gravity-fed to a heat-affected zone (HAZ) around a particular weld suspected of containing numerous defects. A bespoke centraliser tool was designed and built to allow the unit to pass through a series of retaining bars and to maintain a steady central attitude for accurate and effective scanning.

A visual record of the internal profile of the caisson was produced, as illustrated by extracts above. Surface defects were highlighted and measured in three dimensions and a comprehensive visual report was issued to the customer for remedial action. The rapid, clear and accurate results generated by the C-Scan system enabled a focused repair program to restore the asset to regulatory levels of fitness for purpose. All issues relating to HSE were satisfied in a cost effective, timely and safe manner.

 

External pipeline measurement

A client had identified a leak in one of their subsea manifolds that forced a shutdown of the infrastructure in which the pipe was located, stopping production. Before the leak could be repaired using an external bracket, it was essential that very accurate, high resolution measurements of the affected pipe could be taken. OceanTools were requested to perform a remote visual surface inspection of the pipe manifold.

C-Scan was deployed into the underwater structure on an ROV manipulator to take scans of the affected pipes. A number of high resolution point clouds were fitted together to produce a full reconstruction of the pipe. The virtual model and derived measurements allowed the client to design and produce clamps that could be fitted to the pipes to seal the leaks and restart production.