Bjørn Melve

Midscale Qualification Testing of End Fittings for High Temperature Flexible Pipes

The qualification of high temperature flexible risers was a critical element in the field development of the Norne and Asgard fields. At a later stage this also included the Kristin field. The high temperature leads to the selection of PVDF as the liner (pressure sheath) material. Due to numerous leaks from pressure sheath sliding in the end fittings of risers with three layer PVDF liners in the middle of 90’s, it was necessary to requalify the end fitting design. An extensive test 10 year program was initiated where mid-scale riser samples were cycled between the minimum and maximum operating temperatures. In the 10 year long test program were some test pipes were subjected to more than 1000 cycles without pressure sheath sliding or a failure. The modified end fittings were qualified for service.Copyright

Composite Drilling Riser on Heidrun: A Decade in Operational Experience

A drilling riser joint with carbon fibre in the main structural body and titanium end flanges was put into service at the Heidrun TLP in 2001. The joint has an internal titanium liner. The joint was the first implementation of an offshore composite riser and was the end result of the Compriser project.The composite riser joint has an internal diameter of 560 mm (22”) and is 15 m (48 ft) long. The joint is a part of the marine riser. The joint has been in service for ten years and has been treated as its metallic counterparts.At the periodic inspection done in 2010, it was decided that the external layer needed refurbishment.Inspection and pressure testing showed that the properties of the joint had not changed during service.Copyright