A new generation of subsea technologies is cutting fuel consumption, improving positioning accuracy and shrinking the carbon footprint of offshore operations
Autonomous and remotely operated underwater drones are revolutionising offshore oil and gas operations, lowering the cost of subsea inspection, repair and maintenance operations, mitigating risk through data collection and reducing CO2 emissions. Long-term deployment of these undersea automatons, however, requires improved battery charging and communications technologies, one example being Blue Logic’s open-standard subsea docking station.
Installed on the seabed, the docking station allows AUVs and UUVs to be permanently deployed subsea by providing access to power for charging and communications, allowing the upload/download of inspection and assignment data. The docking station’s flatbed design connects with resident robots of all shapes and sizes. Eelume’s snake-like drone, Oceaneering’s popsicle-shaped Freedom and Saipem’s mini-armed Hydrone-R will all be able to connect to the open-standard docking station.
Beyond traditional offshore oil and gas, newly developed subsea equipment is playing a pivotal role in the development of offshore windfarms. Designed and built for offshore contractor Van Oord by Soil Machine Dynamics (SMD) in the UK, the Deep Dig-It trencher can bury cables to a depth of 5 m.
The uniquely capable trencher has been developed to bury cables serving the Hollandse Kust (Zuid) offshore windfarm and was delivered to Van Oord in H1 2020.
A tracked remotely operated vehicle (TROV), Deep Dig-It is designed to ‘drive’ across the seabed, creating a trench for the cables while simultaneously inserting the cable and then closing the trench again. It has an installed power of 1,864 kW, allowing it to bury cables into very hard, compacted soil.
Deep Dig-It is controlled by an offshore installation vessel equipped with a crane that launches and recovers it.
Fibre rope crane
“What would an offshore lifting and subsea lowering system look like today if we started with a blank sheet of paper?” asks Imeca offshore business development manager Mattijs Faber. Something like the Agilis offshore crane perhaps? Designed to be incorporated into a newbuild or retrofitted on an existing vessel, the crane uses fibre rope instead of steel wire rope. The weight of steel wire consumes 50% of the offshore crane’s safe working load (SWL) at 3,000 m. Since fibre rope is neutrally buoyant in water, it can facilitate large subsea lifts from smaller vessels.
Agilis has an electric drive and control system for all its winches and slewing. Supercaps are used for peak shaving to reduce the generator load.
New high-density ESS for offshore
A leader in energy storage systems, Corvus Energy is pushing maritime and offshore battery technology further with the development of the new high-density li-ion capacitor ESS Blue Marlin. Corvus Energy incorporated the LiC technology into the maritime-specific Blue Marlin product under a product development agreement with Kawasaki Heavy Industries.
Corvus Energy believes Blue Marlin will be able to sustain very high charge/discharge rates of 550 C peak and 200 C continuous, enabling both energy recapture and fast discharge for high-power load handling.
Precision accuracy offshore
Drill rigs and OSVs require accurate and reliable positioning data for subsea and deepwater drilling operations. A next-generation GNSS receiver, the LD900 – released from Veripos, part of Hexagon – can track four GNSS frequencies simultaneously. When combined with Apex correction services from Veripos, LD900 delivers accuracy levels as precise as 5 cm to provide positioning for deepwater drilling, seismic, construction and survey, says the company.
Capable of multi-constellation and multi-frequency (MCMF) GNSS tracking, the LD900 supports all Veripos correction services, which use Precise Point Positioning (PPP) to deliver high levels of accuracy across the globe. The LD900 receiver supports multi-channel L-Band tracking that provides simultaneous reception of services from three satellites broadcasting Veripos Apex5 corrections, reducing the risk of satellite masking or blocking.