David Paganie
Managing Editor
STAVANGER, Norway -- Subsea 7 has recently installed the first of six production manifolds on the Agbami field offshore Nigeria with an unconventional configuration of wire line and nylon pennant. Kirsti Gaupseth, project engineer with Subsea 7, talked about the installation on Friday, Oct. 12, at DOT in Stavanger, Norway.
Installation of the first 82-metric-ton (90-ton) production manifold in 1,500 m (4,921 ft) water depth was done in less than 12 hours, Gaupseth said. The manifold was set down with the 150-metric-ton (165-ton) crane on theToisas Perseus.
To reduce loads on the crane and dynamic loads on the manifold while being lowered in deepwater, Subsea 7 opted to use two 470-m (1,542-ft) long, 152-mm (6-in.) diameter nylon pennants connected to 100-m (328-ft) wire for the installation, Gaupseth said. "The nylon is close to buoyant in water, adding almost no additional weight to the crane," she said.
The dynamic load amplitude is 36 times greater with the steel line configuration than the nylon pennant, she said.
10/12/2007
