Subsea cable burial campaign for Nexans
Overview
OEG’s subsea team was contracted to deliver a turnkey remedial cable burial campaign for Nexans, a leader in the design and manufacture of cable systems and services. The work scope was executed using OEG’s innovative all-electric controlled flow excavation technology, SEAJET.
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Challenges
The project offered challenges with regards to the operational conditions, presenting tight weather windows to conduct work within and fluctuating tidal ranges.
The specialist OEG subsea team, who are experts in working in these challenging shallow water conditions, successfully demonstrated that the SEAJET system delivers up to 100% more power than any legacy hydraulic CFE systems currently on the market, even when presented with some of the most challenging conditions considered for this type of seabed intervention works.
The project team reported zero downtime, working in aggressively short high-water tidal conditions and ultra-shallow water depths.
Workscope
OEG utilised their innovative all-electric controlled flow excavation (E-CFE®) technology called SEAJET to execute the cable burial campaign, which included trenching and burial of shallow water export cables at an offshore wind farm site in the UK.
Solution
OEG mobilised the SEAJET E-CFE® system onto a 27m ultra-shallow draft multicat vessel for the completion of the work scope. The equipment spread included the SEAJET tool, electric umbilical winch, power cabin and control cabin. The compact deck space onboard the vessel allowed OEG to demonstrate the adaptability of the equipment spread, which was easily accommodated onto the vessel deck which had limited available space.
The advanced control system built into the SEAJET tool allows performance to be monitored and optimised in real-time, ensuring reliability and maximising project uptime. Other major benefits include vastly reduced CO2 emissions, eliminating the risk of high-pressure, high-volume oil spills into the marine environment and reduced noise pollution.
By harnessing an all-electric powertrain, E-CFE® commands the same power supply and vessel deck footprint as older hydraulic technology but delivers up to 100% more usable power at the seabed, even in the shallowest of water depths.
OEG successfully delivered the cable burial campaign utilising the SEAJET system, achieving trenching depths that were on average 2.5m deeper than existing hydraulic technology, in a single pass of the tool. In some areas, a single pass of the SEAJET tool was able to lower the pipeline up to 4m deeper than other CFE technologies.
Testimonial
There is no doubt that the SEAJET is a very powerful tool, and we are extremely impressed with the burial results from this campaign. The environmental benefits of the SEAJET were greatly appreciated and the OEG team were highly skilled and professional in successfully delivering the project for us.