As of October 2007, and for the next 40 years, around 10 million Brits will be boiling their morning tea and keeping their houses warm using Norwegian gas from the Ormen Lange field in the Norwegian Sea. However, as gas prices across the country are soaring, October 2007 may seem too far away. But don't despair, there are some good news; Norwegian gas will arrive early this autumn.
The southern part of the Ormen Lange field's pipeline Langeled - between the Sleipner field in the North Sea and the reception facility in Easington - has been completed and will start exporting gas to the UK as early as October 2006.
The Ormen Lange field was discovered in 1997 by Norwegian oil and energy company Hydro. It is located in a subsea depression left by the Storegga slide 8000 years ago, 120km to the west of Kristiansund on the West coast of Norway and at around 850m to 1,100m below the ocean surface. Only the gas field Troll, which has approximately 1,300bcm recoverable gas, is larger in Norway.
Meeting 20% of the UK’s gas need
Hydro is the operator for the development phase of the project and the field is likely to double the company’s gas exports by 2010 and simulatenously make Norway the second largest gas exporter in the world. Ormen Lange’s licensees include a list of heavyweights within the industry such as Shell (17.0375% ), Petoro (36.4750%), Statoil (10.8441%), Dong (10.3420%) , ExxonMobil (7.2286%) as well as Hydro (18.0728% ),
The field is ranked as one the largest developments in the European offshore industry with gas reserves of nearly 400 billion cubic metres (bcm) and development costs of around NOK66 billion (approx £5.9billion). It is also the first large-scale offshore field where all production stations lie on the seabed. Production will reach its peak in around four years time and supply up to 20bcm of gas per year – that constitutes the entire annual energy demand in Norway or, more importantly for the tea-drinking Brits, enough to meet around 20% of the UK’s gas needs for the next decades.
Tackling the rugged seabed and -1.2ºC
As with the rugged Norwegian landscape on land, the seabed where the gas will be extracted and transported is of a similar kind. The gas pipes need to bend around peaks of hard clay up to 40m to 60m tall and with lots of rock. Therefore, the engineers who are building this complex system of underwater pipes and stations, had to map out the best possible route to make sure that any pipe would rest comfortably on the seabed. This has been done with the help of unmanned underwater vehicles which outline the sea floor with an incredible level of detail. In turn, this has made it possible to unload millions of tonnes of rocks at several hundred metres of depth to support the pipes, with a precision of inches. Consequently, large suspensions in waters where strong currents exist are avoided and the first 33 kilometers of pipes were successfully placed in June 2005.
There were also other issues to tackle such as the freezing -1.2ºC water temprature on the seabed which forced the engineers to develop the world’s largest anti-freeze system. To prevent the formation of hydrates in the pipeline, two separate pipelines were installed to bring an anti-freeze glycol-based liquid to the transported gas which then worked as a secure flow assurance system. Now, once the gas is onshore, the anti-freeze, as well as liquid slugs and condensate, are separated out.
The Ormen Lange field was discovered in 1997 by Norwegian oil and energy company Hydro and is located in a subsea depression 120km to the west of Kristiansund on the West coast of Norway
Photo: Norsk Hydro ASA
Bringing in expertise
Such a large-scale project demands expertise in a number of areas and during the busy summer period several thousands are employed in the building of the processing plants, pipelines and processing plant in Nyhamna, in Aukra municipality in western Norway – with a maximum of 3,000 people working at any time at Nyhamna. In addition, there are people in Belgium, Poland and other parts of Norway who also are building equipment for the field.
Engineers have been brought in to solve the technical and geological challenges the project has posed and they have developed underwater robot technology and advanced installation techniques to help build the 24 wellheads and 1200 km of pipelines. Naturally, the construction of these pipeline required a lot of steel, a million tonnes of it in total, and has engaged a major portion of the world’s pipeline production and laying resources. In fact, the undersea pipeline, named Langeled, is the world’s longest of its kind. It will transport the gas 1200 kilometres from Norway to England via the Sleipner distribution station in the North Sea. The pipeline running from the Sleipner platform in the North Sea to Easington on the East coast of England will start export gas from October this year and the northern section will transport gas from the Ormen Lange field by October next year.
In the UK, a new receiving facility, to be operated by Centrica, is under construction next to the company’s existing terminal at Easington. Here the gas from the North Sea will be pressure- and temperature-adjusted to comply with the inlet requirements of the National Grid Transco’s network in the UK. Should the Easington plant need to be expanded in the future, land in the area has already been set aside.
Protecting people and environment
In times where pollution of the environment and the effects of global warming are increasingly attracting more interest and concern in both the media and the public at large, the Ormen Lange project has from the start focussed on minimising its environmental impact. For instance, due to the conservation of reservoir energy as well as heat recovery from the cooling medium and process heat, and the usage of electricity from the grid to drive compressors, the annual emissions of CO2 at the plant in Nyhamna will be kept at 0.1 - 0.4% of Norway’s emissions.
The fish in the North Sea need not fear; the pipeline has been routed to avoid conflict with fisheries and corals. This was achieved by cooperating with representatives from the fisheries to identify concerns and using sonar, echo sounder and visualisation technology along with recordings from video cameras on remote operated vehicles which mapped the corals on the seabed.
At the Ormen Lange field, discharges are restricted to water-based mud and cuttings as well as the water containing pipeline chemicals which was discharged under the initial pipeline testing and commissioning. At Nyhamna during the production phase, the discharges include cleaned produced water, drainage water and seawater used for cooling. Assessment of the discharges has confirmed that they don’t represnt any unacceptable environmental risks.
And with several thousand people working on the project, their safety is a priority at any time: “The Ormen Lange field shall be developed, operated and decommissioned while preserving the environment, personnel health and assets. The field development shall be completed without injuries,” states the project’s health, safety and environment (HSE) vision.
So in the next decades when British households are using Norwegian gas, they can drink their tea or take a hot bath knowing that the gas has been produced in the most environmentally friendly way and by using the latest technology available. Roll on October 2007!
The undersea pipeline Langeled, is the world’s longest of its kind and will transport the gas 1200 kilometres from Norway to England via the Sleipner distribution station in the North Sea
Photo: Norsk Hydro ASA