Objectif The SCR/FPSO project aims to demonstrate, using full scale tests, a cheaper alternative than the current flexible deepwater riser technology used in Floating Production Storage and Offloading Systems (FPSOs). The project will be based on the steel Catenary Riser (SCR) concept. The project aims to validate the SCR system by the installation of a full scale instrumentated prototype on an FPSO by the year 2000 at 800 meters water depth.The SCR concept applied to FPSOs has the potential to provide a technically cost-effective alternative by using large diameter rigid (steel) deepwater risers. The current methodology involves the use of multiple small diameter flexible risers, as large diameter flexible risers are not commercially available and are unlikely to be economically viable.A wide number of SCR alternatives were studied by the design team to select the most promising solutions during the subsequent phases. Three turret locations were initially considered : bow, mid ship and intermediate. A preliminary assessment of the static and dynamic behaviour under simplified storm conditions was carried out in order to allow an initial selection.The free-hanging catenary alternatives were found to be inadequate to sustain the assigned environmental inputs related to a bow turret position. All the wave configuration showed a good dynamic behaviour, both in terms of maximum top tensions and stresses, with the Lazy S alternatives providing reduced bending moments at the turret attachment.The basic free-hanging case subjected to the motions associated to a central turret has a satisfactory response, confirming the interest in this configuration for situations of moderate offsets and heave excursions. The good behaviour of the basic case made unnecessary to consider other alternatives for the mid-ship turret option on economic grounds. The alternative might result in a viable solution also for the intermediate turret location .A preliminary cost estimate for all the studied alternatives was performed giving a clear confirmation on the economic advantage related to the use of free-hanging risers: they are the prefereed option when utilised in moderate conditions.Dissemination: A technical paper summarising the project achievements was presented in specialised conference in Aberdeen in June 1998 with the participation of major European oil companies and offshore contractors.The SCR/FPSO project will address the problem created by the substitution of a flexible pipe by a cheaper but more rigid one. The Tension Leg Platform (TLP) previous experience is restricted to a case where the system does not move as much (both vertically and horizontally) as in the FPSO case addressed herein. The project will demonstrate that enough flexibility can be introduced in the system by carefully designing the line geometry and by the introduction of flexible elements at critical regions. The design will take into account the more severe motions of the FPSO case and its effects on the system.Currently, SCRs are only installed in two TLPs world-wide, and one is currently planned for a semi-submersible. This project moves the state-of-the-art a step further by addressing the more severe motion characteristics of FPSOs, enabling the installation of the first SCR prototype on an FPSO by the year 2000.The difference in the procurement costs between the SCR and the flexible alternative is estimated to be about US$ 70 M for a specific development which includes 17 risers (900 meters water deep). This is a significant difference in favour of the new technology and has been confirmed in other situations.The project will increase the physical understanding of the complex interactions between the components in an SCR/FPSO system. This will enable the safer design of future installations.The success of the project will represent a significant step forward in the technology of risers for FPSOs. A balance between rigid and flexible risers will be achieved resulting in a better understanding of when to use each type of riser. This should result in a substantial reduction in up-front invetsment costs, and will increase the technical and economic viability of some deepwater oil fields world-wide which may not be exploited otherwise. Champ scientifique natural sciencesmathematicspure mathematicsgeometry Programme(s) FP4-NNE-THERMIE C - Specific programme for research and technological development, including demonstration in the field of non-nuclear energy, 1994-1998 Thème(s) 1 - OIL AND GAS Appel à propositions Data not available Régime de financement DEM - Demonstration contracts Coordinateur REVERSE ENGINEERING LTD Contribution de l’UE Aucune donnée Adresse ARMSTRONG HOUSE BRANCASTER ROAD M17ED Manchester Royaume-Uni Voir sur la carte Coût total Aucune donnée
