Back to subsea's blue skies

October 1, 2012

Blue sky thinking and a bunch of new patents have in recent years heralded Fluor's return with a vengeance to the subsea technology arena after a near two-decade lull. Jennifer Pallanich talks to Fluor Offshore Solutions technology director Neal Prescott about the company's latest offerings and initiatives.

2003 was a year of returns for Fluor: the company re-dedicated itself to the subsea world with the creation of a specialist division, and it brought oil & gas sector veteran Neal Prescott – an engineer well versed in subsea, offshore infrastructure, production and drilling matters – back to run it.

Prescott was originally a component of the Fluor Ocean Services team from its 1968 inception with five people until his mid-1980s departure from the company. Following his return, the subsea division began concentrating on deepwater technology solutions that might be needed in the industry as part of a blue sky effort.

'We identified about 40 topics and narrowed it down to six,' Prescott says. The process was straight-forward, he says: 'We look at an area where we feel there is a need that exists. We do a background check on what solutions there are out there and we come up with one we feel could be competitive.'

The group has since filed for patents on a number of its solutions, ranging from a subsea LNG pipeline to an intelligent choke for deepwater production control to retrofitting components for hybrid riser towers, among others.

To date, no subsea LNG pipeline has been installed, due largely to the fact there has been no need, Prescott notes. Normally, LNG is transferred onshore or through lines installed on trestles above water. One of the most exciting developments since FOS formed, Prescott says, is the patenting of an LNG subsea pipeline in 2004.

The company has some history in dealing with cryogenic products. In the 1970s, Fluor was involved in a gasification project in Saudi Arabia; Prescott, involved with the project, said the proposed solution involving the world's longest trestle structure was expensive and suggested a subsea cryogenic line. 'They told me I was too young and didn't know what I was talking about,' he recalls. Now, he says, when someone mentioned wanting to install an LNG pipeline on a long trestle and he suggested a subsea LNG pipeline, 'they told me I was too old and didn't know what I was talking about.'

Engineering a subsea LNG pipeline meant trying out several solutions. While 36 nickel may have been an obvious steel choice for the pipe for its minimal expansion and contraction properties, Prescott says, nickel prices were rising. A German company, EisenBäu Kramer, was able to make high-strength 9 nickel steel alloy pipe from plate that has been used for LNG tanks. Prescott says the two companies worked together for five years to develop the 9 nickel pipeline manufacturing system needed to make the subsea LNG pipeline. 'The advantage of this 9 nickel over the 36 nickel is that it's stronger. It gives us toughness for the pipeline,' he says. That extra strength happens even when the alloy gets colder, he adds.

Fluor looked to the issues surrounding the US National Aeronautics & Space Administration operational use of vacuum insulated cryogenic pipelines and recruited industry experts who were familiar with the work on vacuum pipelines. 'It became pretty obvious that we needed to do something that would cut down the operation and maintenance issues,' Prescott says. Fluor also worked with Cabot Corporation on a high-efficiency thermal insulation expansion pack system featuring Nanogel technology, which allows the use of a pipe-in-pipe design, sidestepping the need to have a vacuum.

He says a DNV comparison of the subsea LNG pipeline to a trestle pipeline indicated the subsea line carried less risk. 'That confirmed what I had thought for the last 30 years,' Prescott says. With the design's 'fitness for service' certification now finalized with ABS and DNV, the concept is considered ready for commercial use. Fluor is 'now considered one of the prime companies that can offer that solution,' Prescott notes.

Fluor has talked with three companies about using the technology at various LNG terminals, he says. In one case, he adds, Fluor has been selected – 'if the project does go forward.'

Production chokes got some attention, Prescott says, with the company patenting a dual choke for HPHT deepwater reservoir production and an intelligent choke – one that uses a multiphase flow meter – is also getting interest, he says. Beyond that, the company is looking to clean up produced fluids through some subsea separation efforts.

'We're taking that concept of subsea separation to the next step, which is to get the separated material, like water and sand . . . to the point where it's clean enough to release it to the sea,' Prescott says. Being able to discharge cleaned water directly to sea is a keen pursuit in the industry because it will reduce the floater and pipeline sizes needed as well as minimize pumping, he notes, and Research Partnership to Secure Energy for America (RPSEA) is looking into the technology. Fluor is working on a patent for a third stage polisher for subsea processing in ultra deepwater. 'It will achieve a water quality level that would be permissible to inject back into the sea without an environmental issue,' he says.

The new design builds on an existing subsea separation system, used by Fluor in the 1985 Highlander field tieback to Tartan field in the North Sea (OE July 1985). Fluor and Siemens are now working together to develop systems necessary to bring the third stage polisher and the Fluor subsea separation and processing system to fruition.

'The philosophy that we're following will allow the extension of production in fields and will allow you to get rid of water,' Prescott says.

Fluor expects the new system to be commercial in the near future, and will initially target deepwater production applications where there is a need to minimize or eliminate the footprint of floating production facilities.

A concept study on hybrid riser towers for a major oil company around 2000 eventually prompted Fluor to look at how to retrofit components during the life of a system, Prescott notes. Historically, he adds, there has been no easy way to easily replace components during maintenance.

'That's what our patent addresses,' he says, adding the design is meant to avoid having anything that could have an operational issue. Fluor is working with companies that handle connections and coatings on the design, he says. 'The concept is similar but a little different than what's been built in the past. We tried to answer some of the issues that surround the overall design flaws that have been identified in the past.'

Problems have arisen with weight and the buoyancy needed to hold the tower up. 'This is a direction that we're going. The deeper that you get, you have to solve the issue of getting the product up to the floater. There's been some problems in the recent past where the use of flexible lines to go up to a floater have met with failure,' he says. 'You have to address the weight and the buoyancy. You let the water work for you by buoying everything.'

Additionally, he says, Fluor's solution relies on existing technology applied in a different manner. The trick, according to Prescott, was to modify existing ROV clamps, connectors, jumper systems, etc, that could be modified to achieve Fluor's goals. It can be maintained, he adds, by disassembling it. The system can be installed at a lesser cost than what exists in the market, he adds. Part of the solution lies with connector systems that tend to be lighter than normal, he says.

He expects Fluor will start speaking more openly about the technology in the upcoming months. The new design is expected to be commercial in 3Q 2010. The expected first application would depend on operational needs in deepwater production centers around the world, he says.

As most of the world considers alternative energy sources and pollution by greenhouse gases. Prescott notes Fluor has a patent on wind tower support structures. Fluor and Global Industries, he says, have been working together on how to best install offshore wind farms with Fluor handling engineering and Global providing equipment. 'We see that as a growth market and one that we want to focus our attention on,' he says. In January the UK's Crown Estate awarded Fluor and Scottish & Southern Energy (SSE) exclusive rights to develop the Round 3 offshore wind farm zone in the Firth of Forth, off the coast of Scotland (see "Round 3 ups the windfarm ante"). This same Fluor- SSE partnership is developing the 500MW Greater Gabbard wind farm off the coast of Suffolk, which is currently the first of the Round 2 projects under construction and is on schedule for completion in 2012.

Fluor also has been working on a carbon capture system that will sequester the carbon in the form of liquid CO2 offshore in a saline aquifer in a zone below the seabed. 'This could be a growth industry for us, depending on how the world accepts the discussions going on about carbon capture,' Prescott says. The project, he says, will be the world's largest for offshore carbon sequestration if it is implemented.

Fluor has also been focused on flow assurance, especially in deepwater and Arctic environments. Over the last five years or so, Prescott says, the company has developed algorithms for predicting and controlling hydrates and condensate slugs. The system predicts hydrate, wax and slug formation as part of a real-time monitoring system. 'We do see the Arctic investment intensifying,' he adds. OE

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