Snorre TLP Topside Design

ABSTRACT This paper gives a brief description of the topside facilities and integrated deck structure for the Snorre TLP which will operate on Block 34/7 in the Norwegian Sector of the North Sea. Features which contribute to safe, simple and weight/space saving solutions are presented. The paper addresses where new technology is applied to achieve the overall goal of optimizing platform topsides. Comparisons with conventional installations in the North Sea will be presented. TOPSIDE DESCRIPTION Topside Configuration An integrated deck concept (Fig. 1) has been chosen for its cost and weight benefits. The rectangular deck - 124.5 m long and 92 m wide - has a total height of 15 m including a 2 m deep double bottom forming the cellar deck. The deck is cantilevered at either end of the TLP by 1l.5 m. Three main deck levels constitute the overall deck layout: cellar deck, intermediate deck and upper deck. Local mezzanine decks have further been included for support of equipment and facilities. The main structural girders comprise a combination of trusses and plate girders. The six open trusses form the longitudinal girders of the platform, whereas the plate girders span in the transverse direction, providing partitions between the areas. This gives a safe segregation of hazardous and non-hazardous areas. The intermediate and mezzanine decks are simply supported on the plate girders and contribute little or nothing to the global strength. The cellar and upper deck sections have their structural configuration determined by the overall structure and contribute to the global strength. The design of the deck sections has taken into account the requirements for fabrication, lifting, installation and reduction of the structural dead weight to a greatest possible extent. The deck is constructed and assembled at a main site. However, the deck has been designed such that 17 of the deck sections can be fabricated and outfitted at other sites. These approximately 20 × 20 meters deck sections, or preassemblies as they have been called, were mechanically completed to the largest extent possible at the different yards before being transported and lifted into the main frame. Topside Layout The layout meets all of the operational design and safety requirements and at the same time conforms to the normal segregation of hazardous areas found on other Norwegian platforms. The facilities have been layed out in the following sequences (Fig. 2):Living quartersUtility areaDrilling facilitiesWellbay areaProcess areaFlare The main lifeboat station and the Living Quarter is located in the western end on a cantilevered portion of the deck at the maximum distance from the hazardous areas. Adjacent to the living quarters is the utility area with main power plants and control rooms. Also the 4 × 50% fire water pumps are located in this area directly above the columns. The area adjacent to the utility area contains most of the drilling equipment and other utility systems.