AVEVA World Magazine

Pipeline 2008 #1

AVEVA World Magazine | Technology insights and customer successes with AVEVA software

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The Alvheim FPSO Designed for the North Sea by Aibel using AVEVA PDMS Steve Gibbons Principal Consultant – Oil & Gas, Industry Solutions, AVEVA The conversion of the shuttle tanker Odin to the FPSO Alvheim has been an important project for Aibel; AVEVA visited Aibel's Knut Storsveen in their Oslo office to find out more… The Alvheim development The fields that comprise the Alvheim development are on the Norwegian Continental Shelf close to the UK border, in water which is 125 metres deep. It consists of three principal oil and gas discoveries, and is operated by Marathon Petroleum Company (Norway) (65%) on behalf of ConocoPhillips (20%) and Lundin Petroleum (15%). Aibel experienced users of AVEVA PDMS Aibel is the result of the consolidation of several companies over many years. One of these original companies, Umoe Oil & Gas, had been an AVEVA PDMS user since 1998. Aibel's previous experience in the conversion of FPSOs includes Berge Charlotte, Berge Hus, Berge Helene, Chinguetti and Golfinho. The development comprises an FPSO for production, with oil exported by shuttle tanker, and gas via pipeline to the UK. Production from the Alvheim and Vilje (third party production) developments is expected to eventually reach 75,000 net barrels per day of oil equivalent (oil plus gas), with the Alvheim FPSO storing approximately 560,000 barrels of oil. The combined Alvheim development is estimated to contain resources of 200–250 million gross barrels of oil equivalent. The Alvheim conversion, however, has been a very important project for Aibel – it was the first FPSO conversion where the topsides were constructed and integrated in Norway (at Aibel's yard in Haugesund, on the west coast, between Bergen and Stavanger). It is also the first FPSO Aibel have constructed for use in the North Sea, where harsh conditions demand different construction standards and regulations from, for example, West Africa. Accurate as-built information essential For the process of integration (or merging) of the different components associated with the FPSO – specifically the topsides and the hull – accurate as-designed and as-built information was essential. Knut Storsveen System Integration Specialist, Aibel The Alvheim FPSO The Alvheim FPSO is a conversion of the multipurpose shuttle tanker, Odin, purchased from Statoil in 2004. The conversion consists of three main components: the hull upgrade, the topsides construction and integration, and the construction of the Turret Mooring and Swivel (TMS) system. The hull upgrade work was carried out by Keppel Offshore & Marine at their Keppel Shipyard in Singapore. The TMS system was provided by Advanced Production and Loading (APL) AS, Arendal, Norway. Aibel provided the engineering, procurement, construction, integration and completion contract for topside work on the FPSO. The work, including the design and construction of 12 modules, approximately 9,000 tonnes in total comprising production separators, gas compression and dehydration, water treatment and power generation systems, was mainly carried out in Oslo and Haugesund, Norway. Page 28 | AVEVA PIPELINE | 2008 Issue 1 Although it was built as recently as 2001, a 3D modelling system had not been used for the design of the Odin, nor were accurate as-built 2D drawings available. The as-built information therefore had to be obtained by surveying the vessel. The solution chosen was to laser-scan the existing deck structure of the Odin. The original laser-scanning being carried out in Stavanger. One interesting but unforeseen problem was that when the Odin was transported from Stavanger to dry dock in Singapore, the hull structure deflexed differently than when afloat and also expanded with the rise in temperature. These factors meant that later scanning carried out in Singapore, and the subsequent modelling from that data, did not match the modelling carried out from the Stavanger scanning. Consequently Aibel found the integration of the different models (including a PDMS model of the deck modifications created by Keppel) more difficult because of these inaccuracies. The scanning was carried out by Capnor AS, a two-man team taking 110 scans. After checking and registering, the scanned data was imported into Leica Geosystems HDS Cyclone software modules, before exporting to MicroStation, then into AVEVA PDMS using the ImPlant interface.

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