Luo, Michael Y.H. (Floating Systems Engineering Department, Technip Offshore, Inc.) | Zhang, Bob (Floating Systems Engineering Department, Technip Offshore, Inc.) | Harwood, Michael (Floating Systems Engineering Department, Technip Offshore, Inc.) | Maher, Jim (Floating Systems Engineering Department, Technip Offshore, Inc.)
Spar platforms have become one of the most attractive development concepts as the industry moves toward deep and ultra-deep water for oil and gas field development. In general Spar platforms are characterized by limited Topsides footprint i.e. a limited distance between Topsides’ supports on top of the Hull. Due to significant pitch/roll motions, therefore, the structural design for Spar Topsides-to-Hull connections is very challenging. Fatigue strength at the Topsides-to-Hull connections has been a determining factor for the configuration of the Topsides for almost every spar. Nearly all spar platforms built to date have used a welded connection utilizing a casting between Topsides and Hull in order to avoid possible fatigue failure at this connection. In this paper, the connection design of existing Spars are first evaluated and welded Topsides-to-Hull connections are then compared with grouted Topsides-to-Hull connections from various aspects such as fabrication, installation and cost.
The Spar floating production platform has become a standard solution for deep-water production systems in the Gulf of Mexico. Spar platform technology has evolved from the first generation Classic Spar design to the second generation Truss Spar design and the third generation Cell Spar design. The first Classic Spar was the Oryx (now Kerr McGee) Neptune Classic Spar installed in 1996 [Vardeman, 1997]. The first truss spars, Nansen and Boomvang of Kerr-McGee, were installed in 2001 [Thibodeaux et al, 2002]. The first cell spar, Kerr-McGee’s Red Hawk, was recently installed in the Gulf of Mexico in 5300 feet water. Total thirteen production spars, (three classic Spars, nine truss Spars and one cell Spar), have been installed in the Gulf of Mexico. Fig. 1 shows 10 Spars, which have been delivered by Technip. The Cell Spar concept has been developed for relatively small depth water platforms.
Alves, Marco A.A. (Instituto superior Técnico) | Sarmento, António. J.N.A. (Instituto superior Técnico) | Lara, Javier L. (E.T.S.I. de Caminos, Canales y Puertos) | Losada, Iñigo J. (E.T.S.I. de Caminos, Canales y Puertos)