Composite materials have existed in many forms throughout history, from the brick-making depicted in ancient Egyptian paintings to the use of fiberglass on military aircraft in the 1940s.

Today they are providing a new opportunity for global oil and gas operators as commercial pressures and technologically challenging environments have combined to create something of a perfect storm. The desire to go into deeper waters equates to higher pressures and larger diameter pipes, and traditionally this would mean adding more expensive steel. Yet with composite technology, stronger does not have to mean heavier and more expensive.

Baker Hughes, a GE company, (BHGE) has moved a step closer on its composites journey, with the delivery of a new manufacturing module for its Newcastle facility in the U.K. that will allow it to deliver its first composite risers in early 2019.

Commissioning of the composite manufacturing line was completed at the Newcastle plant in November and the company is in the process of manufacturing production-grade pipe for qualification testing, according to Ray Burke, product management executive at the BHGE Flexible Pipe Systems division. Talks concerning qualification for presalt deployment, offshore Latin America, are also underway with several customers.

“While various companies have attempted to qualify a range of partly or fully composite flexible pipes as deepwater risers, we believe that BHGE will be the first to successfully complete qualification and deployment of a dynamic riser in a floating production system with composite structural components,” Burke said.

The company aims to have a prototype riser in service next year, Burke added, noting this is the subject of current negotiations with operators.

Conventional flexible pipe contains multiple layers that perform separate load-bearing functions, and conventional designs may be heavier than rigid steel pipe, which is homogeneous and can be more efficient in carrying load. The additional weight of conventional flexibles impacts not only the raw material usage but also the transportation, installation and the infrastructure needed to hold them in place. Composite flexible pipe solves this problem by replacing the metallic pressure armor layer with an innovative composite bonded liner.

The technology enables use of a “high-performing composite alternative” to the metallic component of the flexible pipe’s pressure armor layer.

While admitting that fabrication of the composite structures is complex, he was confident in the module’s ability—with its automated laser tape placement system—to ensure greater speed, consistency, repeatability and reliability of the production process. The technology also aims to lower costs, while improving productivity and quality.

“Our customers are shooting for deeper waters in a bid to sustain production, which equates to higher operating pressures and larger diameter pipe. That is the beauty of composites,” Burke said. “They will help to reset the equation, providing the required structural capacity without the weight gain, thereby enabling us to side-step some physical limitations.”

This is a dynamic test run where they produce a length of 30 m (98 ft) of pipe and bend it through full life-cycle motions and durations that it will experience during service, and then dissect it. The step is part of the final qualification with customers and for qualification with Lloyd’s Register.

The company uses what Burke called an “unusual” combination—something other than the thermoset bottoms for carbon fiber applications typically used.

“In this application, because we’ve got so much dynamic motion that strains the pipe repeatedly to the structure, the thermoplastic is a much better matrix,” he said before explaining how it is made. “We mostly amalgamate the tapes, so applying layer by layer of tape circumferentially on the pipe, and use a laser to melt and amalgamate the matrix.”

The end result is a solid layer with polymer on the inside and then carbon fiber and reinforced polymer on the outside, he said, adding it’s the “same material with no join, no bonding, so polymer to polymer.”

Part of the so-called “secret sauce” involves the patented quality control module.

“What this does is inspects the composite structure online, so as we’ve made the layer, it comes through an ultrasonic unit,” Burke said. “If we see any voids we have a means to immediately re-amalgamate [and] reheat the polymer to solidify it. That inspection technology came from GE Aerospace, so it’s one of those crossover technologies we’ve been able to harness.”

Burke said the real challenges are the two areas at end of the riser—the seabed and topsides. “At the topside’s hangoff, there is variable tension but also variable bending. Because the fibers are wound all around the pipe circumferentially, we have quite complicated mathematical equations to characterize these forces.

“It is the same with the touchdown. At the point the pipe touches the ground you have compression. Can you imagine if you had orientated fibers and you’re compressing them and they got a kink?” Burke asked. “There were some other attempts at designing risers in the past where people have used the axial components and tried to replace those with composite. It’s not a very appropriate solution for that application just because of the forces.”

The first area of competitive advantage is deepwater and/or high-pressure riser duties. As the composite armor has superior strength to weight characteristics, BHGE is exploring additional applications across a range of depths where the structural reinforcement allows them to adapt traditional flexible pipe geometries to enhance the cost benefit or capability of the product.

—Mark Venables