Equipment Specs

Langeled Pipeline

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The Langeled Pipeline is the longest underwater pipeline, measuring 746 miles (1,200 km) long from Norway to the U.K. Costing 10 million USD to develop, it was constructed for Norsk Hydro to transport 70 million cubic yards (45 million m3) of gas to heat homes in the United Kingdom. The Langeled project will provide the U.K. with 20 percent of its gas supply. Spearheaded by Ormen Lange, the project was completed in 2006; nine years after Norsk Hydro first discovered an oil field 2,953 feet (900 m) below the earth’s surface.[1]


[edit] Construction History

The Langeled Pipeline is said to have been the biggest and most challenging project of its time. Having to contend with excavation and pipelaying in freezing temperatures deep underwater, often on unstable, rocky terrain, workers had many construction obstacles to overcome.

Several Norwegian companies were involved in the planning phase of the construction. Kongsberg Maritime and Norwegian Underwater Institute provided an underwater vehicle to survey the seabed. The Hugin traveled underwater in depths as much as 14,764 feet (4,500 m), along with a referencing vehicle that gave the project’s planners an idea of the conditions in which the project would be commencing. Nexans provided the 155 miles (250 km) of cable for the gas processing plant at Aukura, as well as a C/S Bourbon Skagerrak, a high-tech cable-laying apparatus.[2]

Skanska, a Sweden-based company, took the task of excavating two caverns with two Atlas Copco Rocket Boomer drill rigs that were employed in the precision drilling project. The rocket boomer XL3 C and 353 ES drilled access tunnels and were used for grouting and bolting the tunnels. When the tunnels were drilled, they were supported by stainless steel bolts, each standing 19.7 feet (6 m) high each. Benches measuring 33 feet (10 m) high were also constructed with Atlas Copco equipment: R 0C D7 surface crawler. The Atlas Copco R 0C D7 drilled profile holes 85 feet (26 m) long and blastholes 8.2 feet (2.5 m) deep. The underwater tunnels were drilled by the Rocket Boomer 353 ES and the Boomer H185.

Geir Anders Kildemo from Skanska said of the process: “The seawater pit was the most challenging part of the project to date due to its unusual profile, complicated by the adjacent shaft and the need for connections between pit, shaft and tunnel.”[3]

The construction project continued with the excavation of earth from the seabed from Nyhamna, Norway to Easington, U.K. Specially-built, remote-control excavators called Spiders were used during this arduous process. The excavators played a crucial role in preparing the seabed for the appropriate positioning of the pipes. Excavators removed some rocks that were in excess of 197 feet (60 m) high. In addition, 2.8 million tons of rock were collected and lowered to the sea floor to balance and level the terrain for the pipeline construction process.

Three thousand workers were employed, many of which were involved in welding more than 96,600 pipe sections to be laid underwater. The pipes had to be laid with the utmost care and precision. Approximately 2.5 miles (4 km) of pipes were laid per day with the help of two large pipelaying vessels, the LB200 and Soltaire. The LB200 consisted of four welding stations where the pipes were welded and coated with a special, protective substance. Before the pipes could be laid, numerous tests were carried out to determine if they were watertight and capable of preventing pipe corrosion. As many as 600 people worked together to prepare the pipes

Pipes in the southern section were measured with a 44-inch (112-cm) diameter. The northern section, running from Nyhamna to Sleipner consists of 42-inch (107-cm) diameter pipes. 100,000 pipes were used to construct the pipeline that runs from Nyhamna in Norway to Easington, U.K.

Aker Kværner Subsea developed a compression station, the first of its kind, to allow construction to continue in the depths of the ocean. The pipes were lowered into the water but were not joined just yet. Divers spent approximately 48 hours ensuring the pipes were well prepared for welding. Divers accomplished this task with the help of a Pipeline Repair Habitat, a watertight construction area that could remove seawater from the confines to allow the divers to make any repairs necessary.[4]

A fallrock vessel provided by Van Oord blanketed the sea floor with two million tons of aggregate.[5]

A total of 3,000 workers aided in the construction process by one of the largest European offshore developments. The south section of the Langeled project, from Sleipner to Easington, first became operational in October 2006.

[edit] Equipment Used

[edit] Unique Facts

  • Ormen Lange partners include: Hydro, Shell, Petoro, Statoil, Dong, and ExxonMobil. Hydro devised the development of Langeled during the construction phase.
  • The Langeled project has placed Norway in the top three exporters of gas, along with Russia and Canada.[6]
  • A million tons of steel and concrete were used to construct the pipeline.
  • Once gas is transported, it is received at a facility in Easington where it is processed to meet temperature requirements and then generated through the U.K. National Transmission System.
  • Special pipeline inspection gauges (pigs) were used to remove water and other unwanted materials from the pipes. Pigs typically join two pipes by a pigging loop.[7]

[edit] References

  1. Langeled development below budget., August, 2006. (accessed: 2008-09-25)
  2. Official NorTrade website
  3. Gas Landing Precision. Mining and Construction, 2008-09-25.
  4. No wonder fish swim with their mouths open., 2008-09-25.
  5. Tubb, Rita. Construction begins on world's longest subsea pipeline. BNET, June, 2005. (accessed: 2008-09-25)
  6. Langeled development below budget., August, 2006. (accessed: 2008-09-25)
  7. Cargill, Andrew. Special pigs provided for the langeled pipeline. BNET, August, 2007. (accessed: 2008-09-25)