An Autonomous Underwater Vehicle (AUV) is an unmanned vehicle designed to perform various underwater tasks, such as surveying, mapping, and inspecting subsea structures. More recently AUVs are being used in the offshore energy sector to inspect pipelines and other subsea infrastructure.

Blue Ocean Marine Services were approached by a major energy company, operating in Western Australia, to assist in resolving some of challenges they have had with respect to pipeline surveys. Traditional inspection methods using commercial dive teams or large work class remotely operated vehicles (ROVs) were deemed labour-intensive, time-consuming, and expensive. The company was looking for a safer, efficient and cost-effective method to inspect their subsea pipelines to assess and manage their assets.

The L3HARRIS Iver-3 AUV equipped with side-scan sonar, and an interferometric bathymetric system was selected for the subsea pipeline inspection. The 45kg AUV (operated by 2 offshore staff) was deployed from a small offshore support vessel supplied by the company to survey a total of 34km of pipeline sections. Adopting a 3-pass survey strategy, surveying either side of pipeline and along centerline, plus additional survey requirements, resulted in a total of 152km of survey over the course of 5 days.

The AUV was able to perform the inspection quickly and efficiently, reducing the inspection time from weeks to just a few days, which resulted in a significant reduction of cost. The AUV was able to provide detailed information on the pipeline’s condition, position, and identification of over 200 features of interest, allowing the company to identify and manage any potential issues of concern. The safety profile of AUV operations was also vastly reduced in comparison with traditional approaches such as diving or deployment of large ROV technologies.

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