On Thursday a second gas pipeline was connected to the subsea plant on the Ormen Lange field in the Norwegian Sea. This means that 600 kilometres of gas production and anti-freeze pipeline, as well as a support system control cable, have been laid on one the world's most demanding seabed areas.
The coupling of the second gas pipeline to the end station at a depth of 850 metres on Thursday marked the culmination of several years' planning, detailed mapping and extensive work on the seabed between the field and the Nyhamna gas plant in Møre and Romsdal.
The two biggest pipeline laying vessels in the world, Saipem's S7000 and Allseas' Solitaire, played major roles during this summer's pipelaying. An additional 11 other large, special vessels - and several support vessels - took part in the pipelaying.
Solitaire started laying the gas pipepline on 14 July at a location 33 kilometres from land, where the first phase of laying was completed last year.
On 5 August S7000 was brought in during the most demanding part of the operation, from a depth of 550 metres at the edge of the Storegga slide, 100 kilometres from land, and up to the field.
Close follow-up
Hydro's head of offshore activities on the Ormen Lange development, Einar Kilde, is extremely satisfied that the pipelaying schedule was adhered to, even though the special vessels involved are heavily in demand at the moment. In early summer it was unceratin whether Solitaire would have completed another pipeline laying operation in time to make the Ormen Lange schedule.
"We managed to get Solitaire there in time for the start of pipeline laying in July, and then we hit the jackpot weatherwise. Coordinating the activities of all the vessels involved went very smoothly, because we followed up the different contractors closely along the way. We were therefore able to apply corrective measures when the need arose," says Kilde.
"It's a dream of a job to be project manager for such a strong team as we have had during these operations. Hydro's solid experience of major development projects helps a lot, in that we have specialists who can check up on us and make sure the decisions we take are the right ones," he adds.
720 kilometres
When the offshore activities are completed in the middle of October, there will be as many as 2,600 vessel days to put all the pieces of the gigantic Ormen Lange project in place.
All that remains, before pipeline laying is complete, is the laying of one control cable. This cable will be laid next summer. A total of 720 kilometres of pipeline for gas production and antifreeze, and cables for the support systems, will then have been laid between the field and the land-based gas plant.
For development operator Hydro and partners it is costing NOK 66 billion to develop the Ormen Lange field with its subsea installations, pipelines and land-based processing plant. When the gas comes on stream in October next year via Langeled, the world's longest subsea pipeline, the Norwegian field will be able to supply British consumers with 20 percent of the gas they need.