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The Norwegian Petroleum Directorate (NPD) expects a considerable increase in demand for competence and equipment for decommissioning these facilities in a responsible manner.
On the Norwegian shelf, there are currently 12 concrete facilities, 19 floating steel facilities and 88 steel facilities resting on the seabed. In addition, there are nearly 350 subsea systems. In total, these facilities weigh 6.9 million tonnes, the equivalent of 768 Eiffel towers.
Some subsea and steel structures have already been removed from the oldest fields in the North Sea. Facilities have also been removed from several small fields that are shut down.
Many new facilities will be shut down in the coming years. According to a report from Det norske Veritas (2002), 14 facilities will be shut down during the period 2010 to 2015. Eighteen facilities will be shut down during the period 2015 to 2020.
“There will be a significant increase in decommissioning activities in the time ahead. This will be a very important activity that will require a lot of attention from licensees, authorities and the supplier industry,” says Senior Geologist Øystein Dretvik in the Norwegian Petroleum Directorate.
He adds that the activities are expected to pick up around 2020, and then remain at a relatively high level. Since most field’s lifetimes are extended in relation to original plans, it is difficult to estimate exactly how many facilities will be shut down and when.
Disposals must be processed by the authorities
Shutdown and disposal of facilities is regulated in Chapter 5 of the Petroleum Act. Five years at the earliest and two years at the latest, before a facility is shut down, the licensee must present a cessation plan to the Ministry of Petroleum and Energy (MPE). The plan – which must present the costs and environmental consequences of various disposal measures – must also be sent to the Ministry of Labour and the Petroleum Safety Authority Norway. The NPD will assist the MPE in processing the plans, before the Ministry makes a disposal decision.
The Oslo and Paris Convention (OSPAR) for the Protection of the Marine Environment of the North-East Atlantic forbids dumping and abandoning facilities in the sea – with certain exceptions. Concrete substructures, concrete anchor foundations and steel jackets weighing more than 10,000 tonnes can be left in place. However, before permission is granted for this, a consultation process must be implemented within OSPAR. So far, permission has been granted for leaving the concrete part of the Ekofisk storage tank, including the concrete barrier surrounding it and TCP2’s concrete substructure on Frigg, on the seabed after the superstructure and other equipment have been removed.
As a general rule, pipelines and cables can be abandoned, as long as they are not a hindrance or pose a safety risk for bottom fishing. This leads to pipelines and cables being abandoned when there is no such significant fishery activity, or the cables have been safely buried or covered.
Uncertain cost information
Through tax deductions, the government indirectly covers 78 per cent of the costs associated with shutdown and disposal of facilities. For fields where the government has direct ownership interests, the government covers an even higher share of the costs.
The future cost picture is uncertain. It depends on factors such as general cost developments in the industry, the time when the decommissioning projects start, the access to heavy lifting vessels and the capacity of the facilities receiving and processing disused facilities.
Based on cost figures reported by the operating companies, the NPD has estimated that it will cost NOK 170 billion to decommission the facilities – and that does not include concrete substructures resting on the seabed. This is because the process of removal and transport of these structures is not sufficiently tested. The NPD therefore commissioned a separate study of this topic in 2010, followed by another study in 2011.
The concrete facilities comprise approximately 70 per cent of the total weight of the facilities on the shelf. Three of the twelve concrete facilities resting on the seabed are basically not constructed to be removed.
More scrapping than recycling
“In countries such as the US, it is normal for offshore facilities to be re-used several times,” says Øystein Dretvik.
“But on the Norwegian shelf, they’re mostly tailor-made,” he says.
Even though the steel jacket from Nordøst Frigg has been converted into a jetty, and platform decks are used for training shelf personnel on land, there is generally little reuse of facilities.
Most of the waste from the oil activities is recyclable steel.
In Norway, four facilities have a permit for receiving and processing disused shelf facilities. These are AF Environmental Base in Rogaland County, Aker Stord and Scandinavian Metal in Hordaland County in addition to Lyngdal Recycling in Vest-Agder County. The first three are active.
According to the Climate and Pollution Agency, the facilities have sufficient capacity for receiving and processing waste from the shelf toward 2020.
Since the scrapping facilities in Norway are located on deep fjords and have deep-water quays, it is probable that other countries on the North Sea will consider utilising these facilities in the future.
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