Phillips Petroleum Co. Norway expects to begin removing derelict platforms from Ekofisk field in 2001 but will begin abandonment work this year.
The operator recently switched production in Ekofisk to two new platforms, following an 18.8 billion kroner ($2.4 billion) redevelopment after seabed subsidence made many platforms unsafe.
Earlier this year, Phillips said it would need to remove 14 platforms and pipelines from the field, but a survey had revealed them to be in better condition than expected (OGJ, Aug. 17, 1998, p. 51).
Ekofisk update
At the Offshore Northern Seas conference in Stavanger late last month, Phillips officials briefed reporters on the status of Ekofisk and plans for the field's old platforms.Lars Takla, managing director of Phillips Norway, said there are now 10 redundant installations in Ekofisk, and there will be 14 when redevelopment is completed (OGJ, Nov. 21, 1994, p. 98).
He said the company has recovered 1.4 billion bbl of oil plus associated gas from Ekofisk since production started up in 1971. Now the company expects to recover a further 1 billion bbl of oil before the current license expires in 2028.
This target, said Takla, is based on a 40% depletion of oil in place, or 44% of oil equivalent in place, but new technology may improve the recovery even further.
"Every 1% increase in recovery," said Takla, "means oil and gas amounting to 80 million boe goes to market. The field is now producing 290,000 b/d of oil, almost up to design capacity."
David J. Smith, Ekofisk II project manager, said the field's new processing and transportation platform, 2/4J, has capacity to handle 306,000 b/d of oil and 790 MMcfd of gas.
Phillips is looking to boost oil production capacity to 350,000 b/d once a bypass pipeline for third-party gas production is connected soon.
Kjell Jorgensen, Ekofisk I cessation project manager, said that, in addition to the new 2/4J and 2/4X platforms, only the 2/4H and 2/4C platforms are still in use.
He said the P, G, R, and S platforms, near the old processing and transportation tank platform 2/4T, will be decommissioned first, along with platforms in the outlying Cod, Albuskjell, Edda, and West Ekofisk fields.
The Ekofisk A, B, W, FTP, and Q platforms will be decommissioned later. Jorgensen said all these platforms must be completely removed, although the concrete tank around 2/4T can legally be dumped in the field.
"Disposal is expected to start in 2001," said Jorgensen, "although cleaning, plugging, and abandoning of wells will begin this year. First will be Cod field, then it will likely be one of Albuskjell, Edda, or West Ekofisk."
Well plugging will also begin on the 2/4A and 2/4B platforms within the next 2 years, while a snubbing unit has been installed on Cod platform ready to begin plugging operations.
Cessation plan
Phillips intends to submit a cessation plan for redundant Ekofisk facilities to the government in July 1999. This, said Jorgensen, must contain a disposal plan and environmental impact assessment. Decommissioning and abandonment is expected to cost a total 1 billion kroner ($170 million).By January 1999, Phillips hopes to have identified potential markets for 12 old platforms-10 from Ekofisk, plus the linked Statpipe and Valhall riser platforms.
"We have already sold some Ekofisk drilling rigs to a local company for refurbishment and resale," said Jorgensen. "Demand is high for process modules and topsides. We're optimistic we can recover some value from these old platforms."
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