Subsea And Downhole Components
Composite buoyancy elements, riser arch trays, wellhead enclosures and downhole parts meet service challenges.
In extreme conditions and often hard-to-access installations below the waterline, composites are proving more cost-effective than steel. As much as 75 percent lighter than equivalent steel parts, composite components provide overall system weight and cost savings that enable operations in deeper water. Outstanding corrosion resistance, durability and resistance to high temperatures in subsea and downhole environment reduces maintenance, translating to lower overall lifecycle costs. And as material selection, laminate design and fiber loading are proven in civil construction applications, composites are gaining a share in these similar, specialized offshore applications.
A number of offshore platforms have incorporated the composite components discussed in this chapter. In the North Sea, composite wellhead protection has been installed in Shell’s Draugen field, and riser arch trays were incorporated into the design of the Troll C platform in the Norwegion Sector. Composite buoyancy elements are an important part of the massive Girassol project in offshore West Africa, as well as numerous Gulf of Mexico installations, where vessel motion and ocean currents come into play. And downhole composites exhibit good chemical resistance to produced fluids and, unlike traditional metal components, are electromagnetically transparent and easily drilled out.
“The need for composite components is there,” says EDO Fiber Science’s Randy Jones (Salt Lake City, Utah, U.S.A.). “In the case of buoyancy elements, lighter weight becomes an enabling technology.” Says Arnt Frode Brevik of ABB Offshore Systems (Billingstad, Norway), “We’ve gained acceptance by being competitive with steel with a unique design, but we’re continually seeking new and better variations.”