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Decommissioning

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Module 7b

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Decommissioning

Abandonment and restoration

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    • Addressed in today’s PSA and regulations
    • Field abandonment is coming up in the Netherlands (around 8 billion offshore and onshore, state pays 70 %), North Sea (e.g. Brent field)
    • Carry out abandonment in accordance with best international oil field practice (e.g. Europe, Gulf of Mexico)
    • Do not stop when reservoir is empty! Need to plan how to stop production and carry out decommissioning (Field Development Plan)
    • Carry out well abandonment and cleaning of vessels, pipelines in an environmentally-friendly manner
    • Clean up around installations, including soil and groundwater contamination
    • Leave the area as it was found or better

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Brent Spar

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    • Loading and storage buoy for crude oil in the North Sea, 200 km northeast of the Shetland Islands (British waters)
    • 463 feet high, and weighting about 14,500 tons
    • Served from 1979 until 1991, ready for disposal

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Disposal proposal

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For Brent Spar, two shortlisted options were identified:

Horizontal on-shore dismantling

    • Cost: £41 million
    • Environmental risk since the buoy might break in shallow coastal waters

Deep water disposal

    • Cost: £12 million
    • Low environmental risk since no flipping is necessary
    • Several independent studies confirmed the low risk of deep-water disposal

Shell UK proposed deep water disposal as Best Practical Environmental

Option (BPEO), which met UK government approval. The European

governments were informed and there was no official protest.

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Greenpeace

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Objected to the Brent Spar disposal plan on several counts :

    • Understanding of deep-sea environment was poor, and consequently the effects of the proposed disposal on deep sea ecosystems could not be predicted.
    • Documents which supported Shell's application were ‘highly conjectural’, contained unsubstantiated assumptions, limited data and extrapolations from unnamed studies.
    • A precedent would be set, resulting in more contaminated structures being dumped and undermining international agreements.
    • Dismantling the Brent Spar was feasible, facilities were already in use and decommissioning of other oil installations had been carried out elsewhere.
    • To protect the environment, waste should be minimized and harmful materials should recycled, treated or contained.
    • Greenpeace also alleged that the scientific arguments for ocean dumping were being used as a way of disguising Shell's aim to cut costs.

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Way forward

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    • Shell UK abandoned the plan for deep water disposal.
    • Later study confirmed that the original proposal by Shell UK was the right decision in terms of environmental implication.
    • In January 1998, Shell agreed to reuse much of the main Spar structure in the new harbour facilities being constructed.
    • The process of lifting the Spar, cutting it into pieces and transporting them to the site was complex and time-consuming. While echoes of the environmental debate continued in the background, the decommissioning process was finally completed in July 1999.

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Schoonebeek oil field

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    • The Schoonebeek field was discovered in 1943, and more than 250 million barrels of oil had been produced before the field was shut-in.
    • The abandonment of the field in 1996 was justified on economic grounds, based on the techniques and infrastructure available at the time. Oil prices in the early 1990s were very low, between $11 and $18 a barrel. Recycling water was adding between $1 and $3 per barrel to the operating costs
    • The filed abandonment included the abandonment of all (wellhead) locations, metering stations, installations, cables, pipelines and roads, including all disturbances of the soil quality. Finally, the area has been prepared for cultivation and transferred over to the owners. During the project, approximately 1 million m3 of contaminated soil has been removed and more the 2 million m3 of groundwater extracted.
    • Souring oil prices have inspired NAM to consider redeveloping one of Europe’s largest oil fields. A 3D high-resolution seismic survey has lowered the structural uncertainties and horizontal drilling, in combination with new recovery procedures, means that the abandoned Schoonebeek Field could yield a further 100 million barrels of oil.

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Key messages

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    • EIA for exploration drilling and field development must include abandonment.
    • The responsibility of bearing the costs of decommissioning must be clearly established prior to well production.
    • When approaching the abandonment phase, carry out a specific EIA with adequate public consultation.

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Thank you

UNEP-Norway Partnership

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United Nations Avenue, Gigiri

PO Box 30552 – 00100 GPO Nairobi, Kenya

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www.unep.org