Image
Engineering, preparation, removal & disposal of the original Valhall DP drilling platform (topsides, jacket and bridges) from the Norwegian North Sea.
Company : Aker BP
Location : North Sea, 280 km off the Norwegian Coast
70 m
Water depth
Scope of work
- Engineering, preparation, removal & disposal (EPRD) of 6800-tonne drilling topsides (DP), 4350-tonne jacket & connecting bridges
- Pre-lift preparation work (incl. underdeck scaffolding & removal of obstructions under cellar deck for access to lift points, installation of shear brackets and uplift restrainers on legs, cutting & removal of caissons, removal of bridge obstructions, installation of bridge pivot guide, NDT critical joints)
- Cutting of grouted platform legs
- Transfer of topsides from Pioneering Spirit to cargo barge & load-in to disposal yard (Stord, Norway)
6800-tonne
drilling topsides (DP)
4350-tonne
jacket & connecting bridges
Image
Specials & challenges
- Offshore preparations carried out in both “cold” and “live” oil and gas platform environments in Valhall field
- Removal of decommissioned facilities from live field
- First-time deployment of all Pioneering Spirit’s lift systems on the same project (TLS, JLS & 5000-tonne crane)
- Topsides 1500-tonne difference between estimated lift weight (5300 tonne) and actual lift weight (6800 tonne) requiring modifications to selected load-in barge
- Tight vertical clearances between Pioneering Spirit and topsides during removal due to field subsidence
- Small horizontal clearances between TLS and platform (small platform results in lift points close to legs and caissons)
- Pre-lift activities and welding close to the splash zone
- Barge-to-barge ‘rollover’ transfer method for topsides load-in operation to yard
1500-tonne
difference between estimated lift weight
Image
Image
Image
Display on a map
Off