Obiettivo It is generally recognised and accepted that by the end of this century, oil production from offshore North West Europe (and, indeed, the Mediterranean) will be in water depths of up to 1000 m.It is also a recognised fact that many of these fields will be 'marginal' in nature, and development decisions will depend heavily on the economics of various schemes. Increasingly, the use of tension leg platforms, semi-submersibles and other compliant structures is being specified as part of the development of deepwater fields. Cost reductions in capital expenditure for such systems are of paramount importance.This proposal is concerned with the development of a new and innovative structural framing concept for external pressure vessels which will eliminate the need for ring stiffeners for components such as TLP and semi-submersible columns and pontoons. The concept is simple and relies on membranes in tension supported by tubes spaced around the perimeter of the section.The design study has commenced with an external pressure vessel structure for a submerged buoy to be utilised as part of a deepwater mooring system. The structure is approximately 7 metres in diameter and 15 metres in length. It is similar in size and complexity to the inner columns of the latest design of semi-submersible drilling vessels. Preliminary cost studies indicate that the design is more cost effective than conventional internal stiffened compression cylinders and spherical buoys.The main design phase of the project is now progressing towards an automated design proceudre for submerisble cylinders which could be utilised for a variety of purposes. The design procedure automatically sizes the components of the structure and produced a bill of materials and weld volume for fabrication cost estimating.The design procedure then produces a detailed finite element for elastic analysis of the submerged cylinder to current design standards to confirm the member sizes and fatigue strength. A further procedure will produce a finite element model for non-linear collapse analysis to determine the utlimate strength of the vessel.The project will finish with a detailed proposal for experimental testing of a model prototype which will be promoted as a second phase of the concept development.The proposed structural framing concept has the potential to bring an entirely new technology to the oil industry. External pressure vessels are used as buoyancy tanks for fixed jackets, as columns and pontoons for floating semi-submersibles and tension leg platforms (TLP's), as buoys for offshore tanker loading and for the support of risers or mooring lines, as extra buoyancy tanks near the top of articulated columns and towers and as subsea habitats and diving vessels. External pressure vessel technology is also extremely important in structures for the Arctic which much resist the pressure of ice. It is clear, therefore, that if the new technology proposed for framing external pressure vessels can be proved to offer cost and/or weight reduction benefits over existing methods employing stiffened compression shells, it could benefit the design of virtually every type of structure now being used or proposed in the offshore industry.The new technology proposed eliminates all of the internal ring stiffeners normally found in external pressure vessels and is, therefore, purposely designed to lend itself more readily to cheaper fabrication technology making extensive use of automatic welding methods. Furthermore with the major structural behaviour being tensile the plating thickness is reduced therefore resulting is a significant reduction in material weight and cost as well as fabrication costs.The two key technical questions with this concept are whether it has an adequate reserve of strength at collapse and whether it can be detailed to eliminate fatigue problems. These two subjects are the main activities of this research programme and they will be thoroughly investigated using the latest methods of non-linear finite element analysis. Programma(i) ENG-HYDROCARB 2C - Programme (EEC) of support for technological development in the hydrocarbons sector, 1986-1989 Argomento(i) 1.9 - PRODUCTION SYSTEMS Invito a presentare proposte Data not available Meccanismo di finanziamento DEM - Demonstration contracts Coordinatore Billington Osborne Moss Engineering Ltd (BOMEL) Contributo UE Nessun dato Indirizzo LEDGER HOUSE FOREST GREEN ROAD FIFIELD SL6 2NR MAIDENHEAD Regno Unito Mostra sulla mappa Costo totale Nessun dato
