Cost Efficient System Design for a North Sea High Pressure Water Injection Flexible Pipeline Development

Due to the need of costly reel vessels and sophisticated long lead materials for rigid pipeline water injection systems, flexible flowlines with duplex inner carcass have lately been more used as they can be installed with less costly construction vessels and provide a cost effective, a competitive lead time and a compliant material system. The North Sea flexible Subsea water injection development consisted of installing a Subsea water injection template with a first time Subsea tieback to a very congested North Sea field. The conceptual design of the fast track field development was awarded in July 2008 and final tied-in system test was successfully performed in November 2009. This paper will present a cost efficient system design that reduced the project material, fabrication, installation and intervention costs. The paper will present how added value was given to the project by implementing a state of the art 3D in-place FE model in an optimized system design removing one expansion spool, significantly reducing amount of rock dump intervention and preventing modification to template design.