Processes
Design Issues With Tendons
A composite tendon is essentially a rope made from small-diameter rods, which are pultruded with carbon fiber. Multiple rods are gathered together and twisted slightly to form a strand, using typical wire rope stranding methods. Depending on the performance requirements, 10 to 40 strands, about 2 to 3 inches/5
Read MoreDesign Issues
Typical FRP pipe is reciprocally filament wound with a fiber angle of ±54.75° relative to the longitudinal (0°) axis. This architecture satisfies stress loads in both the circumferential (hoop) and longitudinal (axial) directions for most pipes and pressure vessels. It withstands the in-use pressure, ther
Read MoreSome Design Issues
A variety of resins can be used for offshore applications, depending on the requirements for the final product. General-purpose polyester offers a low-cost option that provides greater corrosion resistance than steel. Isophthalic polyester provides somewhat better corrosion resistance, while vinyl ester is pre
Read MorePetrobras Pioneers Topside Composites
Petrobras (Rio de Janeiro, Brazil) was the first major oil company to experiment with molded gratings in the 1980s, though these early products proved unsatisfactory due to wide variations in mechanical properties. However, advances in pultrusion and filament winding technology coupled with the availability of
Read MoreComposite Tether Goes To Sea
Conoco and KOP have manufactured a prototype of a carbon fiber composite tether that could extend TLP production to depths exceeding 10,000 ft/3,000 m. The design has undergone extensive static testing and fatigue loading and has been verified through hydrodynamic model testing. Sea testing is being planned.
Read MoreSubsea Wellhead And Pipeline Protection Covers
Wellhead and pipeline protection covers are required under the Norsok regulations for subsea installations in the Norwegian sector (Standard U-002, Subsea Structures and Piping System). Traditional steel wellhead covers are very large — often more than 50 ft/15m square — to allow ROVs access to the Christmas t
Read MoreStudies Support Viability Of Composites
Numerous studies have compared the performance and cost of steel and composite tendons. Conoco, Norske Conoco A/S (NCAS) and KOP headed several projects to qualify composite TLP tethers prior to launching a full sea test. In a recent study, they compared steel and composite TLP systems in water depths up to 9,
Read MoreA Different, All-Composite Approach
Fiberglass Structural Engineering Inc. (FSE, Bellingham, Wash., U.S.A.) has patented its innovative concept for a hybrid fiberglass and steel platform. Approximately 50 percent of the volume of a conventional steel spar hull would be replaced by hollow filament-wound Eglass and vinyl ester tubes, from 10 ft to
Read MoreComposite Accumulator Bottles Perform In Service
A riser tensioning system for a TLP consists of a tensioning ring and framework, with four to eight hydraulic cylinders — each with an attached pressure vessel or “accumulator bottle” — to support and allow movement of the rigid riser pipe. Installed in the riser wellbay, this primary structural system is desi
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