Semisubmersible vessel moves spar across Atlantic

One of the hull sections for the Genesis spar production structure is shown being loaded onto a semisubmersible heavy-lift vessel in Pori, FInland. The sections were transported to near Corpus Christi, Tex., for assembly.

A semisubmersible, heavy-lift vessel carried the two main hull sections of the Genesis spar production structure from Pori, Finland, to near Corpus Christi, Tex., in two consecutive voyages.

The sections were hauled on Dockwise N.V.'s vessel, Transshelf. The Aker Rauma Offshore yard in Pori was the construction site, and the sections will be assembled together at the Aker Gulf Marine yard at Corpus Christi. Both Atlantic crossings were made on the Transshelf in 24 days, according to Dockwise.

The sections, each with a 122-ft diameter, have lengths of 377 and 328 ft and weigh 10,842 tons and 15,861 tons, respectively.

Load out

Dockwise says to load the sections on the semisubmersible heavy-lift vessel required that the sections first be transversely skidded from the construction quay over the side of the vessel. Next, the vessel Transshelf was submerged so that the cargo could be rotated into the final stowage position. Tugs assisted in the rotation process.

For optimum stability during loading, transport, and discharge, Dockwise stowed the sections at 12° and 26° transversely to the vessel centerline instead of 100% longitudinally.

Genesis

The Genesis spar production structure is part of a joint venture development project of Chevron USA Inc., Exxon Corp., and Fina Oil & Chemical Co. The structure will be placed in 2,600-ft of water in Green Canyon Block 205, about 150 miles from New Orleans.

Chevron is operator of the project.

Chevron has described the spar, when assembled, as a 705-ft cylindrical hull with a 122-ft diameter. When installed offshore, about 650-ft of hull will be beneath the water line.

The hull will support both production and drilling facilities.

Installation plans call for a 14 anchor-pile, chain and wire mooring system to maintain the spar over the well pattern.

Genesis will be the second spar production facility in the Gulf of Mexico. Oryx Energy Co. operates the first production spar, Neptune, installed in late 1996 in 1,930 ft of water.

Production from Genesis is planned to begin in 1998.