Case Study

Efficient data capture on 36-inch riser confirms asset condition.


Oil and Gas


South America



In November 2023, Oceaneering was contracted by a major oil and gas operator to complete a work scope in the Southern Carribean using our Ocean Patriot dive support vessel (DSV).

While working with the client on the dive scope, they requested assistance with additional work: confirming the extent of external wall loss at two locations on one of their 36-inch risers.


Previous inspection of the asset was completed using an internally deployed, in-line high resolution magnetic flux inspection tool.

Data gathered indicated that there was 70% external wall loss at the first location and a 30% external wall loss at a second location. The client requested a more detailed report with sub-millimetric measurements to confirm the defect size. A detailed report of the defect was required to perform integrity analysis and confirm how the riser could be kept online safely.

Our Solution

Oceaneering considered several in-house and vendor-supplied inspection technologies, from computed tomography (CT) scanners and acoustic resonance to light detection and ranging (LiDAR) methods. Based on the client’s requirement for a timely inspection including swift importation approval, in addition to precise determination of anomaly size and location with respect to adjacent structural members, Oceaneering’s Advanced Subsea Visual Metrology (ASVM) solution was selected.

By combining the system with Oceaneering internal quality assurance processes and competencies, we were confident we would be able to derive the measurements in line with the client’s sub-millimetric accuracy requirements. The ASVM system was easily mobilized and provided the ideal functionality for recording the necessary still imagery and video in 4K.

Each inspection location was meticulously cleaned prior to imagery and data collection was monitored by Oceaneering’s onshore based survey and data management teams, enabling increased collaboration and immediate feedback on data quality. Oceaneering’s processing quality, combining the skills of our personnel and in-house developed automated quality control and processing workflows, proved pivotal to capturing and delivering exceptional data.

The team's expertise also proved invaluable when an anomaly location presented in previous inspection documentation proved incorrect. The team leveraged the ROV-based inspection solution to locate the defect at the same elevation but at a different location, enabling the full data collection for depth and size.  

ASVM External Pipeline Wall Loss on Riser
ASVM Wall Loss Measurement

The photogrammetry acquisition was completed successfully and without incident.

Oceaneering’s in-house teams processed and analyzed the data, generating deliverables including a thorough report, tri-axial measurements, 3D models, stills, and video from the inspection.

The team also used the ASVM solution to model additional jacket members and structures surrounding the riser that may prove important to the client should intervention and additional engineered solutions be required.

AVSM External Wall Loss Riser

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