Walking Behaviour and Mitigation Strategies of the Deepwater Tullow TEN Project Swaged Pipe-in-Pipe Flowlines

摘要

The TEN development project offshore Ghana (operated by TullowGhana Ltd and partners) includes one 6” gas production and six 8” oilproduction infield flowlines. The flowlines lengths vary from 3.2 km to7.2 km and are located in water depths of 1200-1800 m. In order toachieve a high level of thermal insulation, these flowlines are fabricatedfrom swaged pipe-in-pipe systems, developed by ITP. The pipes aredouble jointed and assembled onshore to produce double joint units ofswaged pipe-in-pipe which are welded together on the J-lay vessel. AnIzoflex layer is wrapped onto the inner pipe within the annulus. Thisnovel configuration ensures excellent thermal insulation characteristics.This paper highlights the engineering and computational challengesfaced and the efficient solutions developed during detailed design ofthese flowlines. All design activities and numerical solutions wereperformed in house by Subsea 7.