Gulf Marine Services’ latest SESV benefits from a unique cantilever unit and workover unit
Last year’s ADIPEC saw the unveiling of Gulf Marine Services’ (GMS) latest, and arguably its most innovative, vessel. This year, GMS Evolution will not be making an appearance at the conference, but having recently gained ABS certification, it is instead preparing for its first commercial work.
The E-Class vessel was built in Mussafah by Abu Dhabi-based GMS. The company builds and operates a fleet of 14 self-elevating support vessels (SESVs) – also known as jack-up barges – of which the Evolution is the final vessel of seven MSC Gusto DP 2 designs commissioned over the last few years. The Evolution will join other similar vessels in the fleet, including the Enterprise, Endurance and Endeavour, all launched by GMS since 2010.
With an overall length of 81m, a variable load of 1,700-3,200 tonnes and berths for up to 150 personnel, the Evolution is not too dissimilar from other jack-ups on the market. Built for work in water depths of up to 80m, it may not compete for the work undertaken at deeper deployments by larger vessels, but nevertheless boasts some impressive and world-first engineering.
At the rear of the vessel is a removable cantilever skid system and well workover unit (WOU). This system can move the drill floor up to 15m aft of the ship (and up to 8m transverse), allowing it to be manoeuvred over a platform or subsea well.
Speaking with InnovOil by phone, GMS CEO Duncan Anderson explained the strategy behind the innovation: “We were subcontracting much of the deck services but we decided that we could do it ourselves and add value to the deck of our barges, so we developed the cantilever system. It’s not particularly innovative in its idea – it is essentially what a drilling rig has, allowing you to skid over the wellhead. We have been conducting services with our lighter units using wireline coiled tubing, etc.”
Anderson noted that the decision was mainly led by the over-specification and cost of larger drilling rigs: “We commissioned a survey and found out that about 30% of what a drilling rig does in shallow water is well intervention. Really, though, for intervention, a drilling rig is like using a sledgehammer to crack a nut.” By adding those extra capabilities to a lighter, faster barge, the result is a much more efficient and cost-effective system.
Cracking the market
Developed in partnership with Dwellop, a Norway-based designer of topside handling systems for well intervention, the Evolution’s cantilever system allows GMS to offer the kind of well workover and intervention work that was previously only performed by jack-up drilling rigs. The result is the drilling and intervention capabilities of a jack-up with the speed and flexibility of a barge.
According to Dwellop, the WOU system is hydraulically powered with rack & pinion hoisting and a pipe handling system capable of running and handling range 3 drillpipe of up to 14.5 metres. The cantilever system itself has a pulling capacity of 250 tonnes and the capacity to drill wells of up to 15,000 feet (4,570m). Moving at speeds of up to 1m per minute, the WOU can be positioned over the furthest well slot from the ship in under 30 minutes.
This system is means the Evolution can undertake operations such as plugging and abandonment (P&A), light drilling, change-out of submerged pumps and completions.
On board, the drill floor and pipe deck also benefit from considerable use of automation. An automated pipe handling system feeds pipe to the travelling assembly, and an automated roughneck secures pipe connection. Efficiency and flexibility are therefore the key to GMS’ offering. Unlike a jack-up, for example, the Evolution is capable of a self-propelled speed of more than 8 knots, thanks to four 1.2-MW thrusters. Moreover, because it is self-propelled, the Evolution can also be deployed faster than a comparable drilling rig, and in a wider weather window. While a tug-towed rig could take up to two weeks to set up, a four-legged SESV jack-up can be secured over the wellhead in around 12 hours.
“We can go alongside a wellhead and deploy this in something like 45 minutes, and then we can sidetrack wells, do P&A, remove submersible pumps – even drill, but we’re not trying to reinvent in the drilling market,” Anderson added.
Coupled with an initially lower day rate than a comparable rig, GMS believes there are substantial savings to be achieved in deploying more vessels like the Evolution.
Dwellop has designed and supplied GMS with another system for lighter well intervention with wireline and coiled tubing. In addition, however, the cantilever is also retrofittable onto three of the company’s other SESVs – a process likely to be carried out in the near future as the clients witness the capabilities of lighter vessels like the Evolution. “It is very much a case of proving this to client and then we can retrofit this to other assets. We’re streets ahead of the competition…this isn’t two years’ work, the idea goes back many years and we’ve only really taken it seriously over the last three years when we rolled it out,” Anderson said.
That boldness seems to have been rewarded by the company’s client base. He continued: “We’re seeing a lot of interest. It’s been requested by clients before, but oil companies are not marine experts, so it is down to someone like use to take a chance.”
With industry classification now confirmed too – in September the Evolution became the first such SESV with ABS SEU certification – GMS can also show the vessel working, which should help to build confidence in the industry too.
Looking ahead, the next 18 months could be a busy period for the company. In mid-2017, GMS began a 36-month contract with a national oil company (NOC) in the MENA region, and is due to begin two new long-term contracts in 2018 in support of European offshore wind projects.
As for the GMS Evolution itself, it does not currently have a charter, but Anderson said he was “confident we will have it on hire in the near future.”
Given the industry’s requirement for savings, particularly in time and efficiency, the proving of such a system may mark the beginning of new trend in shallow-water intervention – and Evolution, rather than revolution, will continue to be the watchword for GMS.