ONS: Lighter is better

23. aug. 2000 - 09:06

According to Development Manager Harald Wiken of Kvaerner Oilfield Products KOP, this means that all techniques that can reduce these extremely capital-intensive investments are very welcome to the accountants. This has put the engineers back at the head of the table, and their expertise and creativity is in demand as never before.

Composites are the answer

“Fibre-reinforced plastic (FRP) composites offer excellent answers to most questions that are raised in connection with the development of the new, deep and/or distant fields”, claims Wilken. He receives good support for this, not least from chartered engineer Stig Bøtker of the same company. FRP offers a high specific strength and rigidity, low weight, good corrosion resistance, good fatigue properties and low LCC. The lighter material means a virtuous circle for the offshore solutions: lower weight of the equipment to be handled means less demands on the handling equipment, which can then be built simpler and lighter. This again means that whole platforms and other installations can be built lighter and also that the floating ones can have better sea-handling properties.

Plastic platforms

KOP and Conoco have signed an agreement that enables the two companies’ unique expertise in advanced materials to be combined. The first product of the alliance was a holistic study designed to answer two questions: “Is there a broad need for composite materials offshore?” (Phase One): and, “Can it be done, and is it cost-effective, to build entire installations of such materials?” (Phase Two)

Phase One of the study identified a number of input areas in which FRP offshore would have a lot going for it: risers, mooring equipment for floating and anchored TLPs, and the TLPs’ deck and hull structures. Phase Two confirmed the researchers’ findings from Phase One: yes, it is quite possible to build everything identified in Phase One and to defend the operation of such structures from both an engineering and a financial point of view.

Regulatory framework wanted

“The lack of rules and criteria, together with what we might call emotional barriers, led to our postponing the development work on TLP hull and superstructure,” explains Harald Wiken. “On the other hand, we decided to go full steam ahead on risers and TLP anchoring equipment. An important cause reason is that use of composites here could reduce costs by 20 to 25 percent, for an ultra-deepwater TLP, that is, a floater without drilling equipment on board.”

Big challenge

“High-pressure composite risers are perhaps the biggest engineering challenge in offshore right now,” continues Wiken. “It is therefore essential to be able to demonstrate the system in the course of the year, not least so as to be able to remove the emotional barriers I mentioned. We hope that a powerful demonstration of the soundness of the project will once and for all dispose of the impression that “plastic is plastic!” and open the door to innovative thinking in this area.

When the project CompRiser, backed by Statoil, Shell, Chevron, Petrobras, Norsk Hydro and EU Thermie, proves to be a success, we will see much greater use of “plastic” offshore. Light, strong, rigid and cost-effective materials will gradually replace the materials that made their debut when oil was drilled on the plains of America and in the shallow waters off Baku – when the black gold could be found only twenty metres down in the sediments.

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