Phillips Petroleum Co. Norway expects to begin oil and gas exports from new platforms in Block 2/4 Ekofisk field off Norway this summer, following a massive redevelopment necessitated by seabed subsidence.
The operator plans to shut in production at a 14-platform complex centered around Ekofisk this August and to transfer most operations to a new wellhead platform and a transportation/processing platform.
Phillips installed the 2/4-X wellhead platform in October 1996 and 2/4-J transportation and processing platform in August 1997. On Aug. 7, the field will be shut down, and production will restart from new facilities Aug. 23.
The operator reckons the massive redevelopment program is 95% complete and will be finished as scheduled. Total cost is estimated at $2.65 billion, 15% below budget.
Next year, Phillips will begin shutting down the older platforms, with five to be decommissioned within 3 years. The company is studying abandonment options and intends to submit a plan to government in 1999.
Ekofisk was discovered in 1969. In 1971-79, Phillips developed the field as the center of a complex with satellite fields Eldfisk, Tor, Albuskjell, Cod, Edda, and West Ekofisk. Embla was tied back in 1993, while two third-party fields have also been tied back.
In 1984, Phillips discovered that the seabed in the Ekofisk area was subsiding, and in 1986 began jacking up platforms and installing extension pieces to raise them by 6 m. This was not enough to prevent subsidence recurrence. Jacking was also impossible for the giant concrete tank platform at the hub of Ekofisk complex, which acts as a transportation and processing center. Here, protective barriers were installed around the outside of the tank.
In 1994, the Norwegian Petroleum Directorate said Phillips would have to take action or shut down the tank platform in 1998, when subsidence could take the tank platform's protective wall below the North Sea's 100-year wave height (above sea level).
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