Greater Plutonio is a large subsea development of five fields (BP 50%, Sonangol/Sinopec 50%) inrndeepwater offshore Angola Block 18. The development comprises an FPSO connected to some 43rnsubsea wells by some 130 km of infield flowlines, which were commissioned and delivered first oil inrnOctober 2007. An EPCIC contract was awarded in 2004 to a consortium of Acergy and Technip forrnthe design and installation of the complex subsea systems. The design had to consider not only thernflow assurance issues of long distance tie backs, but also the potential for lateral buckling and pipewalkingrnunder the anticipated operational cycles. As a starting point, the Atkins Boreas SAFEBUCKrndesign principles were used, supported by specific test programmes that included fatigue testing andrndetailed pipe/soil interaction testing. Following the successful completion of the installationrnprogramme, detailed monitoring of the performance of the flowlines during hydrotest and earlyrnoperation was carried out to confirm system integrity and validate the assumptions used in design.rnThis paper will cover several aspects of the challenging design for the flowline systems, therndevelopment of the test programmes, the installation, and survey techniques used to establish thernoperating performance as well as an assessment of the actual performance against designrnpredictions.
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