Planys conducted underwater inspection of an oil and gas terminal in Rotterdam. The terminal is used for berthing vessels to move hydrocarbon products. Inspection with divers was unsuitable due to safety risks associated with the practice. Further, some of the piles had corrosion protection wrapping/insulation and it was not desired to remove the same for corrosion mapping. Planys was asked to explore sophisticated underwater NDT methods of assessing corrosion in the piles without exposing the bare surface to evaluate the risk and suitably plan for rehabilitation.

Scope of Work: Underwater visual inspection, thickness measurements (by waterjet cleaning & ultrasonic thickness (UT) measurement) & corrosion monitoring (without cleaning using PEC) at 3 jetties in the same terminal.

Planys Solution: The visual inspection was performed using Planys’ ROV Beluga equipped with high resolution camera, high pressure water-jet cleaning nozzle, Ultrasonic thickness measurement probe and Pulse Eddy Current Probes on a gimbal mount.

1. Over 150+ PEC and 80+ UT measurements were taken across the 3 jetties.
2. High pressure water jet cleaning pump and nozzle mounted on the ROV was used to clean the soft marine growth from the pile and ROV was maneuvered to touch the structure with a contact ultrasonic thickness measurement probe.
3. Following a calibration phase of PEC, the ROV was navigated to the surface of interest and measurements were recorded. Results obtained were benchmarked against those  from a conventional UT survey performed by professional divers 2 years back. The overall condition of the jetty, in the presented case, was assessed to be healthy.
4. PEC was found to have great advantages over conventional UT as there was no need to remove insulation or coatings & also it eliminated the need for cleaning of marine growth. PEC was found to be 3 times faster than conventional UT.
5. All data sets were plotted against geo-tagged CAD drawing of every pile at every jetty on the Planys Analytics Dashboard (PAD) with localised click-to-view video feature.

Images captured during PEC measurements being performed by the ROV without cleaning

Images captured during the calibration phase of the inspection for the following techniques pulsed eddy current & conventional UT

Figures shows measurements displayed on Planys Analytics Dashboard (PAD) & Consolidated thickness estimated using the ROV-PEC system