An economic analysis also showed that a fixed installation yielded the best internal rate of return on the huge investment involved. While a monohull FPSO basically represented the cheapest option, a fixed structure was recommended because it best satisfied Shell’s stated reliability and storage requirements. In other words, this solution represented an improved but not final version of the concept presented in the plan for development and operation (PDO) of Draugen. Fotnote: E-mail fra Dag N.jensen plattformen et unikt konsept, utbygging, illustrasjon, forsidebilde Illustration: A/S Norske Shell/Norwegian Petroleum Museum This aroused such great interest that the company revised its choice of concept, asked for further documentation, and ended up going for a GBS. Olav Olsen calculated and calculated, Tor Ole put the drawings in my letterbox during the night and I took the first flight to Stavanger the next day to present the drawings to Shell with some verbal cost and planning estimates. I talked with Tor Ole Olsen at the Dr Techn Olav Olsen consultancy, and we agreed to create a monotower platform. We, in other words NC, could not give up that easily, so I told Shell there and then that we had a better solution and agreed to meet the company in Stavanger at 08.00 the following day. Then Shell called me – I think it was Serge Leijten – to say that they had now decided that a semi was the best option. NC construction manager Dag N Jensen recalls the process: Photo: BP Norge A/S/Norwegian Petroleum MuseumĪfter all, this construction company could point to great success during the 1970s and 1980s with its Condeep design, not least on the Statfjord and Gullfaks fields. plattformen et unikt konsept, engelsk, Olav Olsen. While Shell considered various solutions – floater, steel jacket (support structure), gravity base structure (GBS) and so forth – Norwegian Contractors (NC) promoted its concrete option. All the options had to satisfy the same operational assumptions in terms of production capacity, wells and transport capability. This quartet was then subjected to a year of further detailing and comparison with the implementation plan, the economics of the project, general operations optimisation and key uncertainties with the proposed technology. – a weather-adapted monohull production floater with possible oil storage and offloading (FPSO) – a semi-submersible platform with attached storage ship – a fixed concrete platform with integrated topsides Finally, the spar was laid down in the dock for further dismantling.Four options remained for further consideration in May 1986. After completion of the down ending into the horizontal floating position, the spar was transported to the Kvaerner dry-dock, suspended in the Rambiz cranes. Subsequently, the Rambiz lifted the bottom end, while a tug controlled the heading of the top of the spar coming down. A subsea lifting frame was installed at the bottom end of the spar. First the Rambiz lifted the helideck and topside from the spar. Eager.one positively assessed Scaldis’ plan which included our previous recommendations. Decommissioning of the Draugen FLPĪfter a contractor switch, Scaldis got the job with its HLV Rambiz. One of the ideas was a lifting frame, like a bucket, at the bottom end of the spar. We produced a full report with notes, comments and possible solutions to Shell. The contractor’s plan did not take into account the structural integrity, how the spar was installed originally and the damage in the spar-middle. After this research we concluded that reverse installation wasn’t possible as the plan suggested.”Įager.one handed over a comprehensive report advising against the proposed plan. By climbing the spar I noticed damage, which we certainly had to include in our calculations. We have extensively studied the Draugen FLPs’ history: how the FLP was filled with ballast water and iron ore and how the FLP was constructed. The fjords are incredibly deep and the spar looked like a little bobber in the big fjord. Hubert: “It was a great decommissioning project to support. For a total insight our senior project engineer Hubert Boter visited the FLP.
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