Ormen Lange is a pioneer project on the Norwegian Continental Shelf. The field is located on the Atlantic Margin in the Norwegian Sea where climatic and oceanographic conditions present some of the most challenging development environments in the world.
Among the challenges we find:
- Location of the field in a deep subsea scar area left by the Storegga slide 8,000 years ago where the seabed, at a water depth of between 800 and 1,000 meters, is heavily undulated with slide debris protruding 30 to 60 meters up from the sea bottom. A major task has been to identify a secure route for control cables and pipelines out of the deepwater production area to shore.
- The interaction between the Gulf Stream and cold polar currents from the north creates special conditions that generate significant forces on risers, mooring, gas pipelines and subsea installations, and presents special requirements for field installations.
- Combined wind and wave forces in the Ormen Lange area are more challenging than in any other deepwater project in the world.
- Water movements in the area caused by polar currents contribute to driving the Gulf Stream. The same water movements bring cold water down from the north and generate water temperatures below freezing for most of the year on the seabed around pipelines and subsea installations in the deep water production area.
All of the above present special demands on the License, the Operator and associated contributing companies. Norwegian engineering and research environments have dominated development of technical design and solutions for the recommended concept for Ormen Lange. Key areas of Norwegian industry and research institutions have been engaged to study and provide solutions to a number of new and unique challenges compared with other oil and gas developments on the Norwegian Continental Shelf, and as a consequence have achieved leading global competence within their particular business areas.
Routing of the gas pipelines in and out of the Storegga scar area has been decided in close cooperation with fishery organizations and authorities. Through extensive survey and mapping operations, in cooperation with recognized Norwegian and international expertise, the stability of seabed masses and slide safety have been carefully investigated. There are no indications that new slides can be initiated, either naturally or from Ormen Lange development activities.
Growing gas market
The European gas market is growing. Both the UK and large parts of continental Europe have forecast a need for more gas. Ormen Lange will be an important supplier with a daily capacity of between 50 and 70 Sm3, giving an annual production of approximately 20 billion Sm3.
This corresponds to supply covering more than 15 percent of UK gas requirements, or Norway's total energy consumption, be that electricity, heating and fuel.
Ormen Lange will require construction of a new gas transportation infrastructure. The associated pipeline project will be one of the largest ever undertaken worldwide. Gas is planned to be transported in a pipeline approximately 1,200 km long from Nyhamna in Aukra municipality all the way to UK, via the tie-in point at Sleipner. Sleipner will only function as a distribution point on the Norwegian side of the demarcation line, to provide the possibility of export to either the UK or to continental Europe as required.
If a decision is made to build a new pipeline, the landing point in the UK will be identified during 1Q 2003, according to plan. Before an eventual decision is taken on a potential new pipeline between the existing tie-in platform and UK, use of existing pipelines on the British side shall be thoroughly evaluated.
Choice between two main development concepts
Both of the main development concepts have been studied and considered from an economic, technical, health, environmental and safety perspective.
During development of the full processing offshore concept, three different platform alternatives were considered: Tension leg platform ("TLP"), Semi-submersible platform ("Semi"), Single spar platform ("Spar").
Given the enormous gas export capacity planned from Ormen Lange, platforms required would have been among the largest in the world, should these have been constructed.
Location and connection of a total 20-24 wells, that must be progressively drilled to drain Ormen Lange, have been studied and developed based on knowledge of reservoir characteristics known since the first well was drilled in 1997 and up to the last appraisal well drilled in May 2002. A particular challenge has been to secure security of gas supply, considering potential hydrates (ice plugs) forming in pipelines in seabed areas where the water temperature is at or below freezing point.
In Spring 2000, Ormen Lange project entered into a cooperation agreement with the county of Møre and Romsdal, through their established "Ormen to Møre" project group. The cooperation had the objective of determining an optimal landing point for Ormen Lange. Fourteen possible landing locations were initially given to the project by the municipality, together with relevant and extensive supporting data. This saved time and allowed the Ormen Lange project to start immediate selection activities. At the end of 2000, 14 possible landing locations were deduced to seven. In June 2001, a further reduction from seven to four sites was completed. They were Tjeldbergodden in Aure municipality, Stavnes in Averøy municipality, Nyhamna in Aukra municipality, and Baraldses in Haram municipality.
These four locations were further developed to a sufficient degree of maturity such that the Ormen Lange could announce on March 14, 2002, that Nyhamna in Aukra municipality was considered the best alternative.
State-of-the-art onshore processing plant
Nyhamna is an attractive location for Ormen Lange and offers the optimal solution, for example, in safety and flexibility regarding future possibilities of establishing a gas node.
The Environmental Impact Assessment (EIA) for the onshore processing plant has already been issued for review to interested parties, while the EIA for the total project is ready for release in the coming days.
The processing plant at Aukra will encompass a total of some 4.3 km2, inclusive of noise and safety zones. Products produced will be sales gas and stabilized condensate (a very light oil). The plant will be operated with power from the grid. Statnett is in the process of preparing new 420 kV facilities, and in addition, a 132 kV emergency power supply. Gas pipelines in and out of Nyhamna are currently planned to be routed through Bjørnsundet. Routing over Aukra and out of Horremsbukta is maintained as an alternative should Bjørnsundet become too narrow.
During construction of the onshore plant, it is estimated peak manning of some 2,000 persons will be reached in 2006. Completed process and export facilities will require some 100 persons for the operations phase as of 2007. The onshore processing plant will be a state-of-the-art facility with regards to health, safety and environment. The plant will be characterized by space provided for effective safety solutions, good approach for marine vessels, high overall safety, efficient use of energy, effective cleansing of production water, re-cycling of volatile organic compounds (VOC), a closed flare system and low emissions.
The onshore plant at Aukra in Møre and Romsdal is designed such that it will be possible to extend the capacity of the plant.
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