The growing use of unmanned surface and autonomous underwater vehicles is reducing costs, speeding data acquisition and improving environmental performance among offshore operators
The growing use of unmanned surface and autonomous underwater vehicles is reducing costs, speeding data acquisition and improving environmental performance among offshore operators
Advances in artificial intelligence, battery storage and charging systems and high-speed connectivity are enabling the development and deployment of a new generation of marine robots in offshore energy operations. These autonomous, semi-autonomous and remotely-controlled unmanned surface vehicles (USV) and autonomous underwater vehicles (AUV) are improving operational and environmental efficiency, increasing safety, reducing costs and accelerating data acquisition. They are being embraced by offshore energy companies for a broad range of applications and transforming how offshore data is gathered, analysed and shared.
Anglo-Dutch oil major Shell has awarded a contract to Australia-based marine survey company Guardian Geomatics to perform a large hydrographic project utilising a fleet of USVs. Starting in June, three USVs will be deployed over several weeks from a ‘mothership’— Ocean Infinity’s subsea construction vessel (SCV) Seabed Constructor — to acquire high-quality hydrographic data over an area in excess of 800 km2 off the coast of West Africa.
“Our ability to utilise multiple USVs simultaneously to collect data across such a vast area, in such a short space of time, and at the same time so materially reducing the environmental impact of the project compared to other service providers, delivers for our clients a truly unique and high value solution,” says Ocean Infinity chief executive Oliver Plunkett.
“By using unmanned surface vessels instead of a conventional vessel, Shell is able to reduce the onsite data acquisition time by a factor of three,” says Guardian Geomatics commercial director Steve Duffield. “Using Guardian’s Seabed-Cloud technology the data is able to be presented to the users with a much quicker turnaround. The fuel usage on the project is estimated to be reduced by a factor 10.”
In March, Ocean Infinity acquired a 25% interest in Guardian Geomatics.
“As with our AUV projects there are material gains in speed and efficiency using autonomous assets in scale to perform seabed surveys,” an Ocean Infinity spokesperson said. “We will also have materially fewer offshore man hours and fuel consumption is expected to be reduced, meaning our approach is not only faster and safer, but has a significantly reduced impact on the environment.”
Fully deployable from any of Ocean Infinity’s three vessels or from shore, each USV has two Yanmar diesel engines that drive twin propellers to a maximum speed of eight knots. The USVs have an endurance of 140 hours when operating at a speed of four knots. The USVs are equipped with Rajant Breadcrumb multi-frequency mesh radio for telemetry between the Seabed Constructor and the USVs.
“Our approach is faster and safer, and has a significantly reduced impact on the environment”
The USVs are equipped with KM HiPAP 502s for acoustic telemetry and positioning between a USV and AUV. The USVs have advanced collision avoidance and standard navigation sensors.
Based on an MT 6022 Mk II design, Seabed Constructor is on contract to Ocean Infinity from Swire Offshore. A special hangar fitted on the aft deck of the SCV serves to house up to eight AUVs. The AUVs can be launched, recovered and serviced in the hangar.
When an AUV is deployed from the vessel it begins its survey once it reaches a set underwater altitude. Once the survey is complete, the AUV returns to the surface and is recovered.
A ‘mission control’ centre called ‘the online room’ on the vessel allows the crew to monitor and operate the AUVs. Once the AUV is onboard, data is downloaded into a high-speed network where it is analysed for sonar contacts and points of interest.
Surveying Grande America
Under a contract with Houston-based marine salvage and emergency response company Ardent, Ocean Infinity used its AUVs to conduct an urgent subsea search, inspection and operations project on the wreck of the roll-on/roll-off cargo vessel Grande America, which sank off the coast of France in the Bay of Biscay on 12 March. The ship was en route from Germany to Morocco when containers on the ship’s weather deck caught fire. The fire spread to other containers and led to the ship listing heavily and finally sinking.
Italy’s Grimaldi Group reported that 2,210 vehicles and 365 containers were onboard on the ship.
In accordance with its antipollution plan, the Grimaldi Group initially dispatched the Boskalis-owned anchor-handling tug supply (AHTS) vessel Union Lynx at the time of the accident to monitor any environmental damage and organise the recovery of any floating containers. Additionally, Grimaldi undertook an underwater survey of the wreck, located in 4,600 m of water, using a ROV aboard France-based Ifremer’s multi-purpose research vessel Pourquoi Pas.
Under its contract with Ardent, Ocean Infinity used its AUVs to locate the wreck, and its ROVs undertook a programme of inspection and operations to determine the state of Grande America.
Last year, Ocean Infinity bought five Hugin AUVs from Kongsberg Maritime to enhance its fleet. Overall, the company has a fleet of six Hugin AUVs which are capable of operating in 6,000 m of water to collect high-resolution data at high speeds. For data collection, each AUV is equipped with side scan sonar, multi-beam echosounder, a very low-frequency sonar called a sub-bottom profiler, high-definition cameras, magnetometer and temperature and depth sensors.
High resolution interferometric synthetic aperture sonar (HISAS) generates high resolution range independent imagery and full swath bathymetry. Coupled with the other sensors on board, the Hugin AUVs produce a robust data set including HISAS imagery and bathymetry, EM2040 bathymetry, sub-bottom profiler data and colour photographs.
The mission was conducted from Ocean Infinity’s vessel Island Pride which had been in Gibraltar prior to the contract. Island Pride is a multi-purpose support vessel, with dynamic positioning class 2 capability based on a UT 737 CD design. The MPSV is owned by Island Offshore, which is majority owned by the Ulstein and Chouest families.
“At a depth of approximately 4,600 m, our data gathering technology was used to assess the state of the wreck, and the high-quality imagery that we collected was pivotal in guiding our ROV team in executing the subsequent intervention,” says Mr Plunkett.
“Emergency response, whether it’s a loss of assets, damaged infrastructure or where there is the potential for environmental impact, is a key part of Ocean Infinity’s offering,” says Mr Plunkett. He says the company maintains a fleet of three mobilised vessels, each with a complete set of the latest deepwater technology tools, deployed across the globe, to respond to such events.
‘Living’ underwater
Houston-based Oceaneering International Inc received the Subsea Innovation Award, sponsored by Maats Tech, at the Annual Offshore Support Journal Awards for its development of the E-ROV system, which is a self-contained, battery-powered ROV capable of operating for weeks underwater without having to be recovered to the surface. It is deployed from a surface vessel in a subsea cage that has a 4G mobile broadband connection buoy that floats on the surface. Managed by a tether system, the E- ROV “unpacks itself” from the subsea cage and is piloted remotely from mission support centres on shore, eliminating the need for a support vessel.
The E-ROV can perform all the common ROV tasks including inspection, valve operation, torque tool operation and other manipulation-related activities. Since the ROV “lives on the seabed” — a so-called resident ROV — it enables operators to respond faster, keep production online more effectively and perform routine tasks with fewer deployments.
“Since the ROV “lives on the seabed” it enables operators to respond faster and perform routine tasks with fewer deployments”
Data or instructions are exchanged by the 4G broadband signal that is transmitted from the integrated communications buoy on the surface.
When the E-ROV is low on battery charge, a support vessel can be deployed to the site to provide a supercharge via a cable to the subsea cage.
Building on the E-ROV concept
On display at this year’s OTC was Oceaneering’s next generation hybrid ROV Freedom. Building on the E-ROV concept, Freedom can undertake autonomous missions in an untethered mode or be remotely piloted from shore for long deployments.
Freedom is fitted with a forward and aft tool changer, aft camera and lights. It has a hydrodynamic shape, achieving speeds up to 6 knots, with a forward-looking high definition camera for infield inspection. For manoeuvrability, it has vectored thrusters and a 360-degree sensor array.
Freedom works out of a smart docking station on the seabed, which allows it to charge its batteries, as well as receive information and upload data to the surface buoy for transmission to the shore-based control centre. It will operate in tethered and autonomous tether-less modes, performing both AUV- and ROV-related tasks, including survey, inspection, torque tool operation and manipulator-related activities.
Oceaneering has ordered hybrid navigation systems from UK-based underwater technology provider Sonardyne Inc for both Freedom and E-ROV.
The two resident vehicle systems are to be fitted with the inertial navigation instrument Sprint-Nav, which combines a Sprint INS sensor, Syrinx 600 kHz doppler velocity log and a pressure sensor in a single unit.
“Tight integration of the separate sensors within Sprint-Nav as well as the use of high-specification ring laser gyros are behind the high performance our customers are seeing from these units,” says Sonardyne sales manager for survey and construction Char Franey.
“They’re free from the calibration routines otherwise required and, because they also run on a unique dual engine algorithm, powering the INS and gyro compass, initialisation is fast and gaps in navigation are few and far between,” he says.
Freedom is expected to debut in offshore trials later this year.
Multipurpose, lower cost
Kongsberg Maritime expanded its line of USVs this April with the Sounder USV System, a multipurpose platform designed to work across different market segments, including ocean survey and fishery duties. It has been developed as a joint venture with Norwegian lifeboat manufacturer Norsafe AS, which was acquired by Viking Life-Saving Equipment last year.
Kongsberg Maritime says the Sounder USV has been configured from the keel upwards as a new platform to deliver hydroacoustic data quality, efficiency and productivity. Operation of the USV is managed by Kongsberg’s K-Mate autonomous surface vehicle control system.
Depending on its mission, the Sounder USV System can be equipped with Kongsberg EM2040 multibeam echosounders for mapping and HiPAP positioning and communications systems for long baseline and AUV support. Other sensors can also be quickly integrated into Sounder’s payload.
“More and more businesses, from many categories within the maritime industry, are starting to see the vast and comparatively untapped potential of USVs as a means of autonomously and cost-effectively harvesting enormous quantities of high-quality data,” says Kongsberg Maritime vice president subsea sales Stene Førsund.
The Sounder USV System is compatible with launch and recovery systems for operation from ship or shore. With an endurance of up to 20 days at 4 knots, the Sounder USV enables productivity at a lower cost.
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