Steel catenary risers for semisubmersible based floating production systems
The DeepStar production riser committee has investigated the feasibility of using steel catenary risers (SCRs) in water depths of 3,000--6,000 ft. Using Sonat`s George Richardson as the base semisubmersible, DeepStar has examined both extreme event response and fatigue life of an SCR made of pipe sections welded end-to-end. Concepts using alternative materials were investigated. This included steel, steel with titanium and titanium catenary risers. The pros and cons of frequency domain versus time domain analysis were investigated with a commercially available analysis package. A second study outlined a definitive analysis procedure which optimized the analysis time requirements. Analyses showed that steel catenary risers are feasible for semisubmersible based floating production systems. For the DeepStar Gulf of Mexico design criteria, alternative materials are not required. The greatest fatigue damage occurs in the touchdown region of the riser. Mild sea states contribute most to fatigue damage near riser touchdown. Wave drift and wind forces provide a significant contribution to touchdown area fatigue damage. Estimated fatigue lives are unacceptable. Although the rotations of the upper end of the riser are large relative to an SCR attached to a TLP, the rotation required can probably be accommodated with existing technology. For the case of product export, steel catenary risers provide very cost effective and readily installable deep water riser alternatives.
- OSTI ID:
- 434057
- Report Number(s):
- CONF-960525-; TRN: IM9709%%491
- Resource Relation:
- Conference: 28. offshore technology conference, Houston, TX (United States), 6-9 May 1996; Other Information: PBD: 1996; Related Information: Is Part Of 28. annual offshore technology conference: Proceedings. Volume 4: Field drilling and development systems; PB: 942 p.
- Country of Publication:
- United States
- Language:
- English
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