Cable-lay Case Study
Flow assurance scope in Norway
A flexible solution for two-vessel execution
For this project, Allseas was commissioned to instal Direct Electrical Heating (DEH) cable onto a flowline system. The role of DEH is to prevent hydrate and wax formation - which tend to compromise hydrocarbon flow over time - by applying heat to the flowline with the use of electrical current. The operation was to be executed in two stages: in Phase 1, a feeder cable was to be installed to power the DEH. The subsequent Phase 2 involved the recovery and rerouting of the feeder cable to a J-Tube on a platform.
Phase 1 was carried out on board the Pioneering Spirt using MDL TTS-2/35 Series Tensioner integrated with a Reel Drive System, for installation of the feeder cable piggybacked on to the DEH cable. For Phase 2, an MDL Level Winder and 3.5m hinged Overboarding Chute was added to the equipment supplied in Phase 1 to complete the back-deck spread, which was used for the recovery and repositioning of the feeder cable in the direction of the J-Tube. The vessel utilised for Phase 2 of the campaign was the Highland Eagle, with the Pioneering Spirit remaining in field for operations.
Scott Stewart, MDL Project Manager, said: "The variance in operations between both phases of this campaign fully highlights how versatile the MDL rental fleet is. From an on-deck piggybacking application to retrieval and lay on the seabed, MDL can provide an optimal spread for a wide range of work scopes. This campaign demonstrated the benefits of our smaller tensioners in the rental fleet, where the compact design of the TTS-2/35 makes no compromises on operation or safety. “The use of a different vessel for Phase 2 presented a unique challenge; however, the close co-operation between the two companies ensured that the campaign was a success."