Intervention allies

Sarah Parker Musarra spoke with FTO Services’ Vidar Sten-Halvorsen to learn more about the new Island Performer intervention vessel, a product of the joint venture between FMC Technologies and Edison Chouest Offshore.

The Island Constructor, whose design was the basis for Island Performer. Photo from Ulstein.

With FMC Technologies’ subsea experience and technology, and marine transport company Edison Chouest’s strong presence in the Gulf of Mexico and Brazil, a partnership appeared to be a natural fit.

“Rather than compete against each other, it would be much better to join forces,” Vidar Sten-Halvorsen, formerly with FMC Technologies, says.

In 2012, the two companies embarked on a well intervention services joint venture, known as FTO Services. Sten-Halvorsen is now the technical director.

‘Ready for international waters’

Formally named in June and delivered to Island Offshore less than one month later on 8 July, Island Performer is designed for riserless light well intervention (RLWI) and inspection, repair and maintenance services. The design is based on another Ulstein-built vessel: Island Constructor, of the shipbuilder’s SX121 design.

Built in 2008, the vessel has worked exclusively in the North Sea, performing well intervention for companies including BP Exploration, Statoil and Premier Oil UK.

With FTO focused on waters outside the North Sea, the newbuild Island Performer required specialized design and technology to serve those other markets.

“It has [been improved upon] and has been designed with more dedicated functions that will take it into international waters,” Sten-Halvorsen says.

The vessel itself is larger to accommodate the equipment necessary to venture into deeper waters. The Island Performer measures 130m, about 10m longer than its predecessor. The reels, operations deck and tank storage have also been enlarged. Additionally, the vessel, an Ulstein X-bow design, features a 140-ton modular handling tower and a 250-ton active heave compensated crane. The ROV launch window has been significantly enhanced with a dedicated moon pool in the center line of the vessel, allowing deployment and recovery of the ROV in higher sea states.

It includes an acoustic doppler current profiler (ADCP) array on the bottom of the hull, similar to what was installed on Island Constructor after operations West of Shetland for BP, where subsea currents wreaked havoc with umbilicals, ROVs and wireline logging tool deployment.

FTO Services solicited feedback from its clients and offshore crews while designing the vessel and its components, and Sten-Halvorsen says that acid stimulation and fluid placement were mentioned as issues in the three regions the company is pursuing. The firm has tried to address these concerns in Island Performer.

Island Performer is the first product of the FMC Technologies and Edison Chouest joint venture. Image from FTO Services.

“The benefit here [with Island Performer] is that you can go in and diagnose the wells because we have intervention capabilities,” he says. “We can go in, log them and understand what the issues are. You have a better diagnosis of the well and you can also then document the effects much better. You can go in after treatment and document before and after assessments of the quality and production of the well.”

The RLWI deepwater stack and the ‘platform-less future’

With rig rates continuing to be one of the main sources of expenditures in offshore exploration and production, FMC Technologies says it is pursuing a “platform-less future” by expanding its subsea offerings. Also, FTO Services Managing Director John Griffin said that rigs are not primarily designed for intervention, whereas vessels can be. “Based on field experience, vessel-based interventions are safer, more efficient and less costly when compared to a rig. The new RLWI deepwater stack solution can deliver these benefits while supporting 80% of the work scope associated with conventional intervention operations,” Griffin said in May.

New 2000m rated deepwater stack, designed without a need for guidepost orientation. Photo from FTO Services.

Sten-Halvorsen says the Island Performer is a “response” to FMC Technologies’ vision.

“Subsea wells will be much more accessible when you have the availability, capacity, and intervention equipment,” he says. “For that future vision, you need this type of vessel with the capability of performing frequent interventions to achieve the same kind of production performance that surface wells have today.”

FMC Technologies is delivering its first RLWI deepwater stack to FTO Services 4Q 2014 for deployment from Island Performer. It is designed to operate in water up to 2000m and in pressures of 10,000psi.

It is the fourth such stack that FMC Technologies has built, with the first generation created from an adopted riser stack, Sten-Halvorsen explains.

Moving into deeper water, the typical deployment method, using guidelines, is not possible. The stack has been designed without the need for guide post orientation and downlines for deploying the upper lubricator section. The umbilical is low-profile with all hydraulic power and accumulation performed on the subsea stack, removing the need for large hydraulic umbilicals, which are difficult to handle in deeper water and problematic in high currents. The umbilical termination is self-engaging when it reaches the stack, requiring minimal interaction by the ROV.

FTO Services said that the designers of this iteration were mindful of the five-year blowout preventer recertification program, so the structure has been simplified, and parts can be changed out or repaired easily.

Diving deeper into the idea of a platform-less future, the Island Performer is also designed to be able to conduct plug and abandonment operations by placing the cement to plug the reservoir.

Sten-Halvorsen calls the vessel “superior,” adding: “Everything is done here to prepare for operations. Everyone will be working in a safe environments and understands what the costs are. It is very different from a vessel of opportunity, where you have to improvise and put everything together for the first time.”

The partnership is now focused on its next project, a new vessel built for construction and intervention operations. The vessel will be built at Edison Chouest Offshore’s Louisiana shipyard in order to be compliant with the US Jones Act, which states that a commercial vessel transporting between US ports must be built and operated by US citizens.

The newbuid will be designed to perform deepwater plug and abandonments, top hole drilling, and both riser-based and riserless intervention. The vessel will measure 492ft (146m) long. Griffin says this project is notable because no other offshore supply vessel of this class has been built in the US before.