Autonomous underwater vehicles (AUVs) are nothing new. They have been with us, in one guise or another, since the 1950s. Differing from their more complex family members, the remotely operated vehicle (ROV), they glide quicker through the water without the need to be tethered to a host vessel by an umbilical.
Historically these torpedo shaped robots have found use predominantly by the world’s navies, deploying them for a variety of uses from intelligence gathering, to training sonar operators, tasked with finding and following something that mimics the attributes of an enemy submarine. They are also favoured amongst the scientific community, ideal for seabed surveys in harsh conditions where you simply can’t sail a vessel or allowing subsea exploration under great swathes of ice at the planet’s poles.
AUVs were expected to find a natural home in the recent development of offshore wind, but the reality has been less pronounced than Westwood previously forecast. At a time when many subsea vessel operators had inspection or work class ROV’s sitting redundant, day rates were such that chartering a vessel and ROV was more cost-competitive. Furthermore, most offshore wind developments are close to shore in very shallow water. This is not the sweet spot for AUV use, and particularly so if other surface vessels are in-situ, forcing the AUV deeper and thus further restricting its market.
In 2017, however, the oil and gas industry adopted AUVs to begin carrying out “life of field inspection” (LOFI), a scope of work focused on assurance of asset integrity throughout its operational lifespan. As developments move to deeper water, the vessels and ROVs needed to inspect subsea infrastructure become more complex, which inevitably drives higher cost. However, the benefits of using AUVs for field inspection go beyond cost savings. They can increase operational safety, reduce environmental impact and reduce personnel at sea.
As shown below, AUV demand in the commercial sector is expected to grow aggressively through to 2022 as LOFI workscopes become increasingly prevalent.
Technology developments are such that AUVs could very soon be constantly patrolling deepwater pipelines and infrastructure, remotely docking on subsea charging stations in-between inspections, meaning downtime (out of the water) is greatly reduced. The docking stations will facilitate the download of gathered data allowing swift diagnosis of problems, thus increasing the operational efficiency of any repair work needed.
When such solutions are considered alongside other innovations like the “permanent reservoir monitoring” (PRM) Equinor has installed for Johan Sverdrup, it is clear that the much heralded “field of tomorrow” is becoming a reality. Problems offshore can be identified earlier and continuous data feeds can be analysed quickly to ensure the longevity of production, safely and cost-effectively.
Ian McDonald is Manager, EMEA Consulting, at Westwood Energy.