Girassol: The FPSO Presentation and Challenges

Abstract

Abstract While the history of floating production storage and offloading (FPSO) is paved with record cost overruns and delays, through the description of the Girassol FPSO project, this paper presents the ways and means used by the Operator-TotalFinaElf - to manage the successful development of the world's largest deepwater FPSO installed in the Girassol field, offshore Angola. The Operator, in developing the FPSO, employed parallel engineering, functional specifications and an early involvement of the industry with an original contracting strategy in order to achieve the Girassol field development in less than six years from discovery to first oil setting a new standard for the Industry. The FPSO described here is now the only visible facility of this pioneering project for the offshore industry (Figure A-1). Introduction Discovered in April 1996, the Girassol field development was sanctioned two years later in July 1998 based on a subsea production scenario associated with a large FPSO, having the following main characteristics:Oil storage: 2,000,000b/dOil Production: 200,000b/dLiquids treatment: 300,000b/dProduced water treatment: 180,000b/dWater Injection: 390,000b/d at 150 barSeawater Sulfate Removal : 400,000b/d < 40 mg/lGas injection: 8,000,000Sm3/d at 285 bar On December 4, 2001 the world's largest FPSO produced first oil from subsea wells through a subsea production system (SPS) and umbilical flowlines and riser towers (UFL) from the 1,400m water depth at the Girassol field. Sailaway of the FPSO from the construction yard in South Korea occurred at the end of March 2001 at a level of completion and commissioning never achieved before for a production unit of such complexity. The completion, just 33 months after the award of a contract based on functional specifications, constituted a new benchmark for future FPSO's. The hull construction subcontract was performed in 19 months and the construction of the 25,000tonnes topsides subcontract was done in 21 months. The initial "fast-track" approach of the Girassol development required the FPSO execution to face the following challenges :Parallel reservoir engineering and surface facilities development;Interface data issues due to different schedule in design development between UFL and FPSO;Management of significant design data changes in throughput and treatment capacity during contract execution; Additional challenges to the FPSO development came from the following adverse events which occured during the course of the project execution:Very buoyant shipyard market;Reallocation of topsides construction and integration site. From the first months after discovery, the Girassol FPSO development history described here presents how the Operatorand its Contractors, through the contracting strategy, the main architectural choices and project execution, faced these challenges and managed the successful FPSO development, crowned by first oil 41 months after project sanction.