The solution

Launched in 2018, the OD OBN programme is a research and development collaboration between partners Shell, Petrobras, SENAI CIMATEC and Sonardyne, supported under the Research Development and Innovation funding clause of the Brazilian National Agency for Petroleum, Natural Gas and Biofuels (ANP).The On-Demand Ocean Bottom Node (OD OBN) programme marks a pivotal step in addressing these challenges, providing a disruptive approach to time-lapse seismic data acquisition.

It is a pioneering new system for acquiring 4D seismic data, which delivers more efficient and cost-effective surveillance of complex pre-salt fields. At its core is a long-term OBN system that can remain on the seabed for several years, capturing seismic data that can be recorded and harvested “on-demand” using autonomous underwater vehicles (AUVs), without the need for repeated deployment and retrieval cycles.

Vast quantities of seismic data are harvested wirelessly using an AUV such as Saipem’s ‘Flatfish’, that implements the through-water optical interface to interrogate the OD OBNs, as developed under a separate ANP programme sponsored by Shell.

This AUV data harvesting approach eliminates the need for node recovery, dramatically reducing vessel time, operational complexity and associated costs.

Key Sonardyne technologies include wireless acoustic communications, required for long range recording control and node clock time offset measurement, and Sonardyne’s BlueComm extremely high-speed optical communications for short range data harvesting to a nearby AUV or remotely operated vehicle (ROV).

The results

Over 2,000 days of trials of pre-production nodes have been conducted across various pre-salt fields including Sapinhoá, Itapu and Buzios. These have successfully demonstrated acoustic control, high-fidelity data acquisition and optical data harvesting using BlueComm, as well as comparing OD OBN data with that of other commercial nodes.

The final round of tests concluded successfully in 2025, with results presented at the IMAGE ‘25 conference in Houston and SBGf Rio’25 conference in Rio de Janeiro.

Next steps

A pilot array of 660 pre-production nodes is currently being produced at a brand-new manufacturing facility in Camaçari, near Salvador, Brazil. Hundreds of these nodes will soon be deployed at the Mero field operated by Petrobras for extended testing and performance evaluation.

The long-term vision is to use autonomy and state of the art communications technologies to enable operators to conduct more frequent ‘on demand’ seismic surveys, with higher fidelity data, at a fraction of the cost of conventional seismic survey methods.

This capability will provide clearer insights into fluid movements and pressure changes within the reservoir, helping to optimise production strategies, improve decision making and enhance recovery rates in one of the world’s most challenging offshore provinces.

OD OBN is not just an incremental improvement, but a fundamental shift in how the industry approaches deepwater reservoir management.

However, ACUA Ocean’s ambition goes beyond surface operations. The company’s strategy is built around a “nested robotics” model. Its moonpool has been designed to be configured for up to 7-tonne payloads, providing high configurability, including remotely operated vehicle (ROV) and autonomous underwater vehicle (AUV) deployments. It’s a “Swiss Army Knife model,” says ACUA Ocean Chairperson Dr Peter Collinson!

PIONEER will act as a mobile offshore hub—launching, tracking and piloting ROVs, AUVs and other subsea sensor packages; operations that would historically require larger crewed ships.

To realise their goals, ACUA Ocean came to us for:

• Accurate, survey-grade positioning and tracking of tethered and untethered subsea systems
• Reliable subsea communications to support remote, over-the-horizon operations
• High data quality while operating in higher sea states
• Seamless integration with industry-standard subsea assets already used by customers
• The ability to operate all systems remotely, consistent with a beyond visual line of sight (BVLOS), uncrewed vessel model

The solution

To bridge the gap between surface autonomy and subsea operations, ACUA Ocean chose to integrate our Mini-Ranger 2 Ultra-Short Baseline (USBL) positioning and communications system onto PIONEER.

Mini-Ranger 2 is our survey-grade USBL system for tracking, positioning and communicating with subsea assets in coastal and shallow to mid-depth waters. It supports divers and marine robotics operations, with optional command-and-control for multi-vehicle fleets.

During integration trials in Plymouth, ACUA Ocean wanted to prove tracking accuracy, but also demonstrate PIONEER’s ability to function as a remote subsea command hub—deploying sensors, communicating with them and managing operations entirely from shore.

Mini-Ranger 2 was integrated with the vessel, using an HPT 3000 transceiver mounted on a temporary pole and an offboard WSM 6+ to validate end-to-end functionality.

The system was interfaced with PIONEER’s onboard power and network infrastructure and accessed remotely via a wide area network (WAN) and VPN connection.

The results

The trials demonstrated PIONEER’s ability to act as a subsea gateway, using our survey-grade acoustic systems.

This included successful remote operation of subsea positioning and communications over a WAN connection, tracking and communication with in-water assets at sea, data harvesting capability and interaction with subsea nodes, and technical readiness for ROV and AUV operations from PIONEER.

This included:

• Remote operability: Operators were able to access, configure and control the system from an onshore remote operations centre, without physical intervention onboard.
• Integration simplicity: Power provision for guest equipment, data connectivity and physical installation were straightforward, supporting the vessel’s modular payload philosophy.
• Data quality: Survey-grade positioning ensured that increased availability and rough-weather capability did not come at the expense of data accuracy or processing time.
• Interoperability: The system aligned with subsea technologies already widely deployed across commercial and defence markets, reducing risk for future customers.

“Through these trials, we successfully proved end-to-end functionality remotely over a WAN, establishing reliable communication between the HPT and subsea transponders both alongside and at sea using Mini-Ranger 2,” says James Cowles, Business Development Director at ACUA Ocean.

“The physical integration was remarkably simple, with the system’s intuitive UI and seamless VPN access allowing us to manage survey-grade technology over-the-horizon with zero issues on software or licensing.

“We were also exceptionally well-supported by Sonardyne’s local technical team here in Plymouth and these successful trials confirm our ability to host and manage survey-grade technology for complex, over-the-horizon missions.”

Proving the foundation for nested robotics at sea

“We’re happy to be supporting ACUA Ocean with our subsea positioning and communications technology to make their vision operational,” says Aidan Thorn, Business Development Manager – Robotics, at Sonardyne.

“With reliable, survey-grade tracking and acoustic communications, Mini-Ranger 2 is a key building block to making PIONEER a fully integrated subsea command and control hub. The flexibility of PIONEER’s deployment options, be they AUV, ROV, subsea glider or towed body fits well with our own philosophy with marine robotics to stay platform agnostic and work across the complete marine autonomous system.”

From enabling resilient positioning in GNSS-challenged environments to supporting multi-vehicle subsea operations, Mini-Ranger 2 provides the dependable subsea layer that underpins safe, scalable autonomy.

Together, ACUA Ocean and Sonardyne are demonstrating how proven subsea technology and innovative surface platforms can work in tandem—delivering cleaner, safer and more capable offshore operations from the surface down.

Overview

WMT is a 6G compatible, high acoustic output power USBL transponder available in two depth versions: 3,000 m and 7,000 m. The 7,000 m version has a higher acoustic output power level for improved long-range operation.

For ROV and towfish tracking, WMT supports responder trigger for faster position updates, an integrated rechargeable Li-Ion battery pack that is charged from the ROV’s power supply and full RS232 communications enabling channel set up, power and gain etc. to be changed from the surface.

At a glance

• Use it with Ranger 2 for deep water, long layback tracking tasks
• High power acoustic output and directional transducer
• Responder mode for fast position updates
• Full two-way Sonardyne Wideband 2 interrogation and reply
• Li-Ion rechargeable battery pack
• Optional remote transducer

An on/off switch (3,000 m only) helps to ensure the battery pack is not discharged when not in use. If an umbilical trigger is not available, then the full Wideband transponder mode provides excellent USBL performance in a small, lightweight package.

Remote omni or directional transducers are available for WMT. These make installation on a ROV easier as the remote transducer can be installed where there is good line-of-sight and is easily replaced if damaged. The main body of the transponder can then be installed within the ROV frame where it is well protected from damage.