Equinor will test an ERRV to deploy a new electric ROV, while other vessels are being used for patrol duty and decommissioning
Norwegian energy company Equinor is employing various technologies to lower costs, reduce emissions and increase efficiency at its offshore production platforms. One of those systems is the E-ROV, a self-contained, battery-powered, remotely-operated vehicle (ROV) system capable of performing for extended periods without being recovered to surface. Communication between the onshore control room and the E-ROV is linked via an integrated buoy, equipped with a 4G transceiver. Enhancing its flexibility, E-ROV is equipped with its own fly-out mini-ROV, providing an additional 75-m radius for activities.
To launch, recover and recharge the E-ROV, Equinor is refitting a chartered emergency rescue and rescue vessel (ERRV), Stril Herkules, with a system being built in Denmark in a test project. Normally, an offshore vessel would be on station to deploy, recover and operate an ROV for a subsea, inspection, repair or maintenance project.
“The whole idea about the E-ROV is to reduce costs, because we remove the need for the surface vessel,” Equinor leading subsea engineer Kaj-Ove Skartun told delegates at the Annual Offshore Support Journal Subsea Virtual Conference. The brainchild of Mr Skartun – and first conceived in September 2015 – E-ROV was built by Oceaneering after it won a tender from Equinor.
Using the “subsea Tesla,” Equinor can reduce CO2 and NOx emissions because a surface vessel is no longer needed and also increase operational flexibility. “We can put the E-ROV in places where we know we are not able to send a surface vessel,” said Mr Skartun. He noted that the E-ROV can be deployed in its subsea garage ahead of time, where it can wait on the seafloor two or three days before operations start. The E-ROV could be moved around the Norwegian continental shelf to perform inspection, repair and maintenance work at various offshore platforms.
“We are anticipating that postponed projects are beginning to restart in the North Sea”
This could be accomplished using emergency preparedness vessels that are already deployed near offshore platforms, said Mr Skartun. “We have vessels that are already paid for that can relocate, they can charge and redeploy the E-ROV system,” he said; this would significantly reduce the cost by “maybe by 80 to 90%,” according to Mr Skartun.
As an example of the potential cost savings, Mr Skartun said Equinor was able to save nine ROV vessel operational days while supporting the semi-submersible drilling rig Deepsea Atlantic at the Fram field. “We had to take care of a subsea isolation valve in case we had to bleed off some pressure from the well,” he said. “The operation took nine days, and if the E-ROV hadn’t been there, we would have had to use a, ROV vessel.”
Owned by Simon Møkster Shipping, Stril Herkules will complete its refit with the launch, recovery and charging system by May or June this year.
Challenging newbuild delivery
When it comes to challenges created by Covid-19, the maritime industry has proved resilient and resourceful. But when the time came to take delivery of its newbuild ERRV from China, Aberdeen-based Sentinel Marine had to think out of the box. “The delivery of Malin Sentinel was one of the most challenging we have faced,” Sentinel Marine CEO Rory Deans told OSJ.
“The 11,451-mile sailing from Dalian Port in China via Singapore and the Suez Canal was due to be made with a Sentinel crew who would have flown out to China. Owing to the pandemic, the seven-week journey, became a far bigger challenge,” said Mr Deans.
“Unable to fly our own crew over, we had to recruit a crew from China”
“Unable to fly our own crew over for this voyage, we had to recruit a crew from China with interviews by Skype, which was a new experience. With no stops possible, they had to take everything needed for the entire journey. It took a lot of work by many people, including banks and lawyers – at a time when most of them were just getting used to working from home – to get the ship to Aberdeen,” he said.
The last in a series of nine ERRVs in a £150M (US$207M) investment, Malin Sentinel arrived in Aberdeen in August.
Mr Deans sees opportunities emerging in the North Sea for his versatile standby and rescue fleet, which can perform duties such as oil recovery, rescue towing and dynamic positioning.
“One of our ships is currently under charter to the European Fisheries Control Agency being used as a patrol vessel in international and EU waters,” he said. Vessels such as Malin Sentinel – at 62 m, with deadweight cargo capacity of 1,500 tonnes and a deck cargo capacity of 600 tonnes – can handle supply work, too.
“Following a year of global deferrals and downward pressure on oil prices, we are anticipating that postponed projects are beginning to restart in the North Sea,” said Mr Deans.
ERRV supporting decommissioning project
Outside the North Sea, Vroon Offshore Services (VOS) will provide the ERRV VOS Pathfinder to support the decommissioning of gas fields offshore Ireland, under a contract with PSE Kinsale Energy Ltd (KEL) under an eight-month award.
A notice from the Department of Transportation, Irish Maritime Administration, reported PSE Kinsale Energy’s subsea wells abandonment campaign would start in March, continuing until November 2021.
The semi-submersible Stena Spey will be used for the decommissioning campaign, which will be undertaken off the south coast of Ireland in three areas: Southwest Kinsale Gasfield (including Greensand location); Seven Heads Gasfield; and Ballycotton Gasfield.
In advance of Stena Spey’s arrival in April, work will begin on the pre-lay of eight anchor mooring spreads at the locations using three Maersk Supply Service anchor-handling tug supply (AHTS) vessels. A total of 600 m of anchor chain will be pre-laid at each of the anchor lines with a 600 ft (183 m) laydown pennant to aid recovery and connection to the rig anchor chain on arrival of Stena Spey. Two dynamic positioning class 2 (DP2), 95-m, Salt Design AHTS vessels, Maersk Maker and Maersk Mariner, will accompany Stena Spey throughout the campaign.
In addition to the term charter AHTS vessels, the rig will also have an ad hoc AHTS vessel, the 90-m, DP2 Maersk Lancer, and VOS Pathfinder as permanent standby vessels in the field throughout all operations.
VOS Pathfinder will remain on station during the time between anchor pre-lay and Stena Spey’s arrival in April. On arrival, Stena Spey will work between these two moored rig locations for an expected period of 90 days (subject to weather conditions), before moving to the PSE Kinsale Energy Limited-operated Seven Heads Gasfield.
Built in 2008, UK-flagged VOS Pathfinder can accommodate 300 survivors. Supporting its rescue, emergency and recovery mission, VOS Pathfinder has two 15-person, MP1000 fast rescue craft, deployed via a Gramplan Hydraulics Scorpion davit and a 15-person MP Weedo 700 rescue craft, launched via a Gramplan Hydraulics GD5 davit.
For mechanical recovery, VOS Pathfinder has a Dacon Rescue Basket and 7-m Dacon Rescue Scoop – a power-assisted method of recovery for retrieving casualties from the water directly onboard rescue vessels. A semi-rigid, manoeuvrable rescue net, the Dacon Rescue Scoop, can be operated by a standard deck crane.