Plans are being pursued by Statoil to dismantle and remove the 2/4-S riser platform on Ekofisk in the North Sea.
This facility previously served as the tie-in point for Statpipe and Norpipe, but became redundant last August when these gas trunklines were linked directly by a new bypass line.
The platform was emptied of hydrocarbons after 13 years in operation, and Statoil has been reviewing its future.
This study produced the clear conclusion that both financial and safety considerations require removal of the topside and bridge to the Ekofisk Centre by the end of 2000.
Recommendations call for the topside to be removed first, explains Johannes Larsen, manager for platform operation in Natural Gas Production & Transport.
The risk of damage to 2/4-S has been increased by seabed subsidence on Ekofisk, which means the topsides are now seven-eight metres closer to the sea surface than when the platform was installed.
"We expect to remove the jacket rather later, when the other platforms on the field are abandoned," says Mr Larsen.
Topside modules will be taken off in reverse order from their installation. A similar operation was conducted a few years ago by Esso on its Odin platform in the Norwegian North Sea.
While topsides and bridge can be disassembled in complete sections and shipped to land for further scrapping or re-use, the jacket will probably have to cut up before it can be retrieved to land.