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Maritime Digitalisation & Communications

An autonomous future for offshore survey

Tue 16 Apr 2019 by Ed Martin

An autonomous future for offshore survey
The Sounder USV has an endurance of up to 20 days at a speed of 4 knots (image: Kongsberg Maritime)

Autonomous underwater vehicles are proving their value in terms of speed, safety and, more surprisingly, environmental efficiency  

In October 2018, Swire Seabed completed its inspection of Equinor’s offshore pipeline systems using a Hugin autonomous underwater vehicle (AUV); the process involved three pipelines between Kollsnes and Troll A. In total, 180 km of pipeline were inspected over two AUV dives.

While a surface vessel was also present, its role was limited to providing positional updates to the AUV and acting as a communications relay with Swire Seabed’s Bergen HQ.

Operated by Kongsberg technicians, the AUV acquired bathymetrical, synthetic aperture sonar and visual data as part of an operation to verify the continued integrity of the subsea pipelines.

Swire Seabed has since ordered a Hugin AUV of its own, for delivery in 2020. Swire Seabed chief executive Arvid Pettersen said the order “demonstrates our long-term commitment to go beyond current industry needs and gear ourselves to meet future market demands through innovation and technology.”

He continued: “We believe that the future of inspections and subsea survey is indeed autonomous and we are excited to be at the forefront of an evolving industry.”

The 5.2 m AUV is containerised and capable of performing autonomous inspections on subsea assets and seabed mapping, while simultaneously acquiring, classifying, interpreting and reporting data.

It will carry Kongsberg Maritime HISAS 1032 synthetic aperture sonar, an EM2040 multibeam echosounder and a CathX Ocean Colour camera and laser. It will also have a Kongsberg Maritime automatic pipeline tracking system.

Kongsberg Maritime continues to expand its offerings in the unmanned and autonomous vehicle segment with new offerings including the Sounder unmanned surface vessel (USV).

A multipurpose platform, the Sounder is designed to work across different market segments including survey and fishery duties. It was developed as a joint venture with project partner Norsafe, chosen for its experience in the construction of vessels for operation in extreme environments.

The Sounder’s operations are managed by the K-MATE autonomous surface vehicle control system, which was developed in partnership with the Norwegian Defence Research Establishment. The K-Mate system provides autonomous, supervised and direct control abilities that allow an unmanned vessel to be programmed to follow survey patterns, autonomously follow AUVs, or track a mothership.

A range of different sensor types can be mounted on the Sounder, including Kongsberg EM2040 multibeam echosounders for mapping and HiPAP positioning and communications systems for long baseline and AUV support. Other sensor types can also be integrated, while the payload can be rapidly changed as the Sounder’s 19-inch rack hardware and hull-mounted moonpool are both removable. The system is also able to operate from ship or shore, and is compatible with launch and recovery systems. It has an endurance of up to 20 days at a speed of 4 knots.

The future of inspections and subsea survey is autonomous”

Kongsberg Maritime’s geoacoustics subsidiary has also brought to the market a compact USV that mounts a lightweight sub-bottom profiler.

The GeoPulse USV has an operational range of up to 2 km and can access areas that more conventional systems are not able to, according to the company.

It mounts Kongsberg Maritime’s GeoPulse Compact sub-bottom profiler, which has more than 100 decibels of noise-free dynamic range, enabling it to provide repeatable, high-quality data without the need for user-controlled analogue pre-processing.

The system combines penetration and resolution to provide a clearly-defined return of sediment layers. It features adaptable digital processing and waveform-selection technology (2-18 khz), allowing for optimal power signatures, pulse shape and configuration for a range of survey tasks. Pulse forms available include frequency-modulated, continuous wave and Ricker.

The GeoPulse USV has only 11% of the power requirements of earlier systems in the GeoPulse range. Its electric motors give it six hours of operational capability at a survey speed of six knots, and it has an interchangeable battery pack. It can be controlled from a laptop computer using GP1000 software, which is interfaced to the deck unit via an ethernet radio modem.

Battery-powered ROVs

Elsewhere, Texas-based Oceaneering recently received the Subsea Innovation Award, sponsored by Maats Tech, at the 2019 Annual Offshore Support Journal Awards.

The subsea technology company beat stiff competition from UK-based Sonardyne International and Denmark-based NKT to win the award, in recognition of its innovative battery-powered ROV system, known as E-ROV.

Maats Tech director Lisa Edwards presented the award to Oceaneering’s ROV operations manager Arve Iversen, who said: “The concept is very daring … I would like to emphasise the importance of Equinor’s contribution. They believed in the concept and in us, making it possible to realise this as a commercial opportunity."

Oceaneering’s ROV operations manager Arve Iversen receives the Subsea Innovation Award from Maats Tech director Lisa Edwards

The E-ROV is based around an eNovus work-class ROV with modified battery technology, optimised to handle peak power consumption and launched from a subsea garage that includes a cage-mounted 100-kW battery pack and tether management system. The eNovus has a 227 kg payload and a depth rating of up to 5,000 m. It measures 2.7 m in length by 1.6 m in width and 1.8 m in height, with a weight in air of 3,400 kg.

The E-ROV can operate for extended periods of time without the need for surface recovery and incorporates technologies such as machine vision learning and augmented reality. It is piloted using Oceaneering’s proprietary Remote Piloting and Automated Control Technology from one of the company’s Mission Support centres onshore, reducing or removing altogether the need for a surface vessel to remain on site.

Connectivity is provided by a data/communications buoy that transmits ROV control data and live, high-definition video over 4G mobile broadband via securely encrypted VPN. The buoy itself features a highly engineered, robust mooring system capable of handling inclement sea conditions.

The system produces efficiencies in a range of areas, including reducing vessel days required to complete operations, reducing the carbon footprint and enhancing the ability of operators to take advantage of favourable weather conditions.

Norwegian energy giant Equinor, formerly known as Statoil, agreed in August 2018 to a three-year contract with Oceaneering for subsea inspection, maintenance and repair activities based around the E-ROV system. Under the terms of the contract, the E-ROV would be deployed in water depths up to 1,000 m on the Norwegian Continental Shelf.

Oceaneering’s origins lie in World Wide Divers, a Gulf of Mexico-focused diving company founded in 1963. World Wide Divers merged with two other diving companies in 1969 to form Oceaneering International. Since then it has expanded its offerings to include products and services that cover the full lifecycle of an offshore oil field, along with work-class ROVs, maintenance services, umbilicals, subsea hardware and tooling.

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