Deployment of a flotilla of AUVs to work on a challenge, and the communication amongst them, could sometime result in a subsea Internet of Things. Source: Ocean Infinity.
AUVs (autonomous underwater autos) are more and more getting used for pipeline surveys and other offshore applications. But they maintain potential for wider use, which depends on operators pushing for advances. “We’ve been at this factor for 20 years; a lot of the expertise components have been there for 15 years. It’s simply that the offshore trade has not persistently pursued them.”
Speaking at a technical session on the opening day of the Offshore Technology Conference, Andy Hill, Global Geohazards Technical Authority at BP, added that almost all technical papers proceed to “have a look at what we all know we will do” as an alternative of taking a view of the longer term with the already-existing capabilities.
For instance, Hill mentioned “swarm” of AUVs can work in parallel, speaking outcomes to one another. Ocean Infinity has developed a a number of autonomous car program to conduct wide-area high-resolution surveys, leading to a pressure multiplier of as much as 6 occasions above conventional strategies. Made up of six AUVs and 6 unmanned floor autos, the flotilla may be deployed from a single host assist vessel. He added that built-in AUV exercise by way of radio, acoustic, and optical indicators could result in the subsea Internet of Things.
Autonomous seabed seismic nodes (“flying” nodes) for deployment by the hundred are being developed by Autonomous Robotics Ltd. Hill referred to as it a “step-change in deployment and restoration modes.”
Not Just for Inspections Anymore
The first AUV was developed in 1957 on the University of Washington. In the 1970s, the Massachusetts Institute of Technology superior the event. L.C. Ricketts, DOF Subsea, mentioned the primary point out of AUVs within the oil and gasoline media occurred in 1990. As exploration prolonged into deeper water, curiosity grew due to the considerations in regards to the tethers required for remotely operated autos (ROVs). Achieving parallel improvement of well being, security, and environment-acceptable launch and deployment was an early impediment.
In his presentation of OTC paper 27920, Ricketts mentioned that utilizing value/km within the tendering course of for AUVs was the most effective—and worst—technique. It compelled AUVs into the oil and gasoline trade on account of the fierce focus amongst AUV service suppliers to drive down their very own operational prices and develop into a “low cost” various. However, it was additionally the worst as a result of it fostered a cost-based as an alternative of value-based mindset, which continues right this moment.
AUV expertise has developed to such a level that since October 2012, DOF Subsea reliability figures of greater than 320 dives yielding over 25000 km of pipeline survey confirmed lower than four% downtime on eight completely different vessels for six completely different purchasers, in accordance with Ricketts, including “these figures should not remoted. Other AUV service suppliers can declare related successes.”
Ricketts mentioned that firms that personal the bigger survey class AUV submarines are sometimes additionally closely invested in ROV property, which can contribute to AUVs being perceived as “struggling for their very own identification.”
Mobilization of an AUV usually takes about 2 to three days, and demobilization takes roughly 36 hours. Surveys may be carried out at four knots and sooner and don’t require the host vessel to be in dynamic positioning mode, trimming time and gasoline prices.
On a single AUV you at the moment are capable of get aspect scan sonar, chirp seismics, multibeam sonar, backscatter, leak detection, high-resolution coloration pictures, and laser scanning—all tied to particular GPS/time coordinates. These larger capabilities equal larger knowledge. Because of the higher-resolution knowledge collected by AUVs and the related massive file sizes, issues for knowledge administration and storage are essential to stop this potential bottleneck.
Case Study: Deepwater West Africa
Sébastien Ghis, Total E&P, and Eric Fischer, Oceaneering, highlighted the large knowledge acquired throughout a pipeline inspection carried out in deepwater West Africa fields of their presentation of OTC paper 27688.
An AUV surveyed 176 particular person flowlines and pipelines over 13 deepwater fields, totaling greater than 978 km of pipelines in water depths as much as 1400 m. Each pipeline was imaged by a number of survey strains and the impartial datasets have been matched in post-processing to inside centimeters.
The suite of AUV sensors comprised aspect scan sonar, sub-bottom profiler, multibeam echo sounders, magnetometer, nonetheless picture digital digital camera, and a bathymetric laser system. The bathymetric laser system alone collected 1,400 factors 29 occasions per second.
To mitigate the big measurement of the info, personalized knowledge processing and workflows have been developed in collaboration with the customers, from the surveyor to the end-client, to tailor the deliverables to the wants of the challenge stakeholders, together with: managers, GIS professionals, surveyors, pipeline engineers, and many others.
Ghis identified that the planning of this advanced challenge required shut consideration to “operational constraints at sea” throughout the AUV inspections, together with floating manufacturing, storage, and offloading vessels; oil-loading tankers; subsea oil storage techniques; manifolds; spools; Christmas timber; and area assist, set up, and seismic vessels.
Fischer mentioned a GIS software was included for knowledge assessment. “All knowledge was georeferenced, which supplies a database which could possibly be used for a ‘time lapse’ strategy to detect any seabed geohazard and subsea gear change or modification over the lifetime of the sphere.”
The OTC papers cited within the article will develop into accessible within the OnePetro digital library on the conclusion of the convention.
