|
Highly optimized steel catenary risers involving the use of special joints in their touch down zone are a feature of modern deep-water systems. Research has shown that including joints of SCR pipe made from titanium is an effective method of improving SCR fatigue and stress response at the touch down zone. Although titanium costs are significant its use in such joints is cost effective by comparison with in-service operational techniques to manage riser fatigue or riser replacement. The couplings between these joints have thus far been flanged. Technology now exists to make the titanium pipe sections weldable.
TDZ-JOINT is a highly fatigue resistant joint that can be used to increase fatigue life of an SCR in the touch down zone region. The joint uses titanium pipe to reduce weight and provide high strength. Using SRP’s shrink-fit technology steel sleeves are used to join titanium pipe sections. During onshore fabrication a single sleeve is used to join two titanium pipes. Offshore two of these sleeves are welded together using standard offshore welds.
- Allows use of Titanium pipe without the need for welding, or the use of bolted flange connections.
- No local stiffening of riser due to flanged connections.
- Improved fatigue performance.
- Cost effective
- Reduces welding and inspection risk
- Efficient offshore installation
- No disruption to standard riser lay procedures
The titanium joints are pre-assembled (e.g. into quadruple joints) onshore using the SRP Shrink-Fit sleeves. At the ends of the sections the sleeves are profiled to allow them to be welded offshore to each other or to the adjacent steel riser pipe. Full onshore finishing and FAT of these sections is then possible, including pressure testing and over coating of the titanium pipe, prior to load out. Offshore installation can then proceed with only steel line pipe welding required. SRP can work with the SCR designers to ensure that these welding and inspection procedures and techniques are standardized as far as possible with those used for the rest of the SCR.
|
Download Data Sheet (pdf)
|
|
