Lightweight, tubular truss for fourth Spar hull

Spars International, the joint venture between Aker Maritime and J Ray McDermott, has been awarded the contract to provide a Spar floating production platform for Kerr-McGee's Nansen Field in the Gulf of Mexico. The two companies announced a few months ago that they were dissolving their alliance, however, this contract was being negotiated before that decision and the work will go ahead as if the alliance were still in place.

Th Swsh
Th Swsh
Aker Rauma's yard in Pori is likely to have enough work soon to see it through to the end of next year.
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Spars International, the joint venture between Aker Maritime and J Ray McDermott, has been awarded the contract to provide a Spar floating production platform for Kerr-McGee's Nansen Field in the Gulf of Mexico. The two companies announced a few months ago that they were dissolving their alliance, however, this contract was being negotiated before that decision and the work will go ahead as if the alliance were still in place.

Whatever the case, the responsibility for delivering the Spar hull and its mooring system is with Aker Rauma Offshore. The hull will be built at the company's Mantyluoto yard in Pori, Finland. This will be the fourth Spar hull to be built in Pori, and the first to incorporate a lightweight tubular truss structure replacing the lower part of the cylindrical hull. The Nansen Spar will be 165.5-meters tall with a diameter of 27.4 meters and a displacement of 30,000 tons. To provide an idea of the weight saving, the first Spar constructed in Pori for the Oryx Neptune development had about the same weight of steel, but was significantly smaller, at 22 meters diameter.

Pre-engineering for the hull has been progressing in Finland for some time and fabrication actually began in mid-May. Delivery of the Spar to the Gulf of Mexico is planned for the last quarter of 2001. Breaking with the practice of the first three Spars, Nansen will be constructed in a single piece at the Mantyluoto yard - the hull structures for Neptune, Genesis and Hoover/Diana were dispatched to the Gulf of Mexico in two parts and, once there, welded together.

During the launch of the hull, lack of buoyancy in the truss section will be compensated by the additional floatation capacity associated with the bottom tank structure, which will ultimately contain ballast. The Spar will be horizontal when it is towed to the field location. Once there, it will be up-ended and topsides installed.

Second project

Aker Rauma Offshore is known to have a second project in the final stages of negotiation. Jarmo Eerola of Aker Rauma Offshore was reluctant to discuss details at this stage. However, he did say that the Pori site was perfectly capable of building two structures side by side.

Nansen is located in the Gulf of Mexico's East Breaks Blocks 601, 602 and 646, approximately 130 miles south of Galveston, Texas. The water depth is 3,700 ft. Production is planned to peak at 40,000 b/d of oil and 200 MMcf/d of gas. There will be eight wells with dry wellheads on the platform.

Aker Maritime will work with J Ray McDer-mott to provide the riser system. Although no announcement has been made, J Ray McDer-mott are thought to be favored to receive the contract to build the platform's topsides.

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