Oceaneering has outlined its latest blueprint for the future of resident subsea ROVs. Andrew Dykes reports from Oslo
The ROV world is changing. As subsea equipment suppliers look to the next generation of technology, the distinction between remotely operated vehicles (ROVs) – the industry’s staple robotic helpers since the late 70s – and autonomous underwater vehicles (AUVs) is becoming increasingly difficult to discern.
Typically, various classes of ROVs have handled the gamut of subsea work from light to heavy-duty intervention, adjusting valves, lifting equipment and supporting divers. Meanwhile, AUVs have tackled smarter but less labour-intensive missions such as surveying, mapping and some automated inspection tasks. But advances in processing power, communications and battery life, coupled with the drive for increased subsea electrification, are opening new avenues for equipment makers.
These new underwater drones will be far more flexible than their predecessors. Batteries will enable them to work without tethers. Greater intelligence will allow them to act without human intervention, yet better communications will mean they can be accessed and controlled remotely whenever necessary. And rather than being deployed one mission at a time, they are likely to spend most of their operating lives at the subsea installations they service.
So far, the concept that has perhaps most effectively conveyed this brave new world is Norway’s Eelume, whose subsea snake design has shown that resident robotics need not resemble anything that has gone before.
Yet another developer leading the charge is Houston-headquartered Oceaneering. “Resident ROVs are something we see coming and something Oceaneering is very serious about,” the company’s ROV operations manager for special projects, Arve Iversen, told journalists during a press tour in Oslo, Norway. Most notably, the company has pioneered the development of a battery-powered work-class model, dubbed the E-ROV. Based on a modified version of its eNovus ROV, this self-contained system is designed to be capable of operating for extended periods without being recovered to surface. Deployed via a subsea garage skid, which also holds the tether management and a 100-kWh battery pack, the E-ROV can leave the cage to work remotely while subsea. The cage is then connected to a 4G connection buoy via a fibre cable, allowing remote control via shore.
In January 2017 Oceaneering was awarded a development contract from Statoil to work on the technology from its workshop and Mission Support Centre in Stavanger. With these proof-of-concept tests now concluded Oceaneering intends to have a commercial model ready for deployment this year, with a view to supplying Statoil and other potential users.
But even as E-ROVs head for open water, the company is already turning to the next iteration of resident solutions – a blueprint it calls Freedom.
While previous craft may resemble a familiar, if repurposed ROV, Freedom represents a new kind of vehicle, purpose-designed from the seabed up. Again the emphasis is on flexibility: the vehicle can be autonomous or controlled remotely, can manoeuvre freely or via a tether, and can be seabed resident or tasked with a long-range mission.
Primarily, Oceaneering sees this as an inspection and light intervention (ILI) craft, but its modular design means the “multi-role drone” should be capable of much more. According to a company presentation, tasks could range from visual inspection and survey work to subsea intervention with “advanced tooling”, depending on the configuration.
As well as being more independent than most ROVs, it can also work deeper. While the E-ROV is rated to 1,000m, it remains constrained by the limits of mooring its communications buoy. By relying on wired communications from the subsea infrastructure itself, Freedom will be capable of working down to 6,000m.
Visually, it more closely resembles the torpedo-shaped design that dominates the AUV market, and its structure follows a similar model. Roughly 3.3m long, Freedom is based around a central module – the white section seen in the images here – which Iversen described as “the core of the vehicle.” This contains batteries, control systems and common sensors needed for most mission configurations.
This core module can then be paired with a range of nose and tail sections, depending on the required mission. Different thruster configurations can be used according to whether the vehicle needs to travel long distances or carry specific payloads. Indeed, one specification shown to InnovOil was configured without thrusters for towing, meaning the same vehicle could be used to gather seismic and sonar data.
Oceaneering is also working on a full electrical tooling suite. Iversen confirmed to InnovOil that options would include a manipulator arm and torque tools, cutting tools and cleaning tools, as well as other probes and sensors. The former two will likely be available first, with others following after testing and qualification. “The tooling will be subsea changeable, so you can have a magazine of tools that can be picked up at the docking station,” he added. This again will allow operators (or the vehicle itself) to carry out multiple operations at the subsea installation, without requiring multiple trips offshore.
When deployed as a resident craft, the designers see Freedom typically operating from one or more docking stations. These stations will enable it to charge batteries, store tools and communicate with the Mission Support Centre onshore. In addition to tooling, these stations will house system components such as navigation aids, battery packs, control infrastructure, etc., as well as a tether management system for missions that require high-power output or high-bandwidth communications.
The docking station itself consists of a launch and recovery basket – which will hold the craft during deployment and charging – and an over-trawlable subsea structure, which will hold tools, batteries and other equipment. This then sits in a subsea base suction anchor sited as desired at the field or installation.
Depending on the requirements at the field, the docking station itself can be equipped with additional batteries for so-called “trickle charging” of the Freedom vehicle if the site has limited cabled power resources. Iversen said that the available power at the station would depend on the constraints of the field, but that Freedom’s power and communications were designed to be tied into the wider subsea infrastructure.
Exactly what battery architecture will be used is still under scrutiny. “We are evaluating which battery technology we want to go for from the beginning but of course development of batteries is something that’s moving very rapidly,” Iversen said, suggesting that the preferred pack may well be changed as the available technology improves.
Docking systems have yet to be finalised. Given that tools and communications protocols vary, Oceaneering appears keen to ensure that cross-party support can be provided for. “It would be beneficial for all parties, we think, to find a standard for the docking station. Not necessarily the whole station needs to be standardised but the interface…if you have inductive charging or inductive data communication connections, you need to be able to use those irrespective of supplier. That’s something the industry needs to land on,” he added.
Statoil may be able to assist in driving this forward – the operator is currently working to establish a joint industry project on this topic, as part of a system dubbed underwater intervention drone (UID) – but the industry is likely a few years from consensus.
Many of Freedom’s features are still in development – and more are likely to be added or modified as time goes on. “After we initiated the idea and took it a step forward, a lot of other applications have come to light,” remarked Oceaneering’s VP and country manager for Norway, Erik Sæstad. But he was bullish on the ability of the technology to deliver on the kinds of savings being demanded by operators: “On the basis of this helping industry getting costs down and increasing flexibility…we believe it’s very, very attractive in terms of the KPIs that operators and everyone is trying to deliver. Especially related to reduced HSE risk and reduced emissions.”
Despite its futuristic capabilities, the age of Freedom does not seem to be too far away. Oceaneering expects to start offshore prototype trials sometime during Q2 2019. Beyond that, Statoil is already considering using similar technology in its Snorre expansion – due online in Q3 2020 – suggesting that full commercial deployment is not far behind.