Challenges
The TEN fields are located in a challenging deepwater environment with a subsea canyon running through them, as well as independent wave loading and high current velocities through the water column. Achieving acceptable strength and fatigue performance of the riser and umbilical global configurations was particularly challenging, and requiring numerous analytical iterations and cross-section design changes throughout the detailed design phase.
The external turret of the FPSO is the world’s largest and is designed to house up to 24 flexible risers and umbilicals. We maintained an up to date model of the whole riser and umbilical system throughout the project, which included future lines, to prevent interference issues during future phases of development.
Results
2H’s independent technical assurance and optimisation of the riser, flowline and umbilical system from FEED through to installation gave Tullow Oil the verification needed to accept the system. We delivered a design review dossier and complete analytical model to Tullow, providing an overall SURF system description, a collation of document references, verification of the P50 riser and umbilical system installed, and a pre-FEED for the future development phases.
As a result of the success of the project, 2H is continuing to support Tullow Oil with the integrity management of the TEN riser system.