Subsea separation has successfully been implemented on the Troll and Tordis fields operated by Statoil,rnPazflor (Total), Marlim (Petrobras), and Perdido and Parque das Conchas/BC-10 (Shell). One objectivernof subsea separation is to separate gas and liquid to optimize working conditions for subsea pumpsrnenabling high recovery factors. The objective of this work was to qualify a two-stage, compact, inlinerngas-liquid separation system with full turndown and slug handling capabilities, consisting of alreadyrnproven components: one Gas-Liquid Cylindrical Cyclone (GLCC) and one InLine DeLiquidiser.rnCompactSep and its separator components and control system were qualified through a comprehensive,rnlarge-scale, real fluid and high pressure test programme at K-lab, a Statoil large scale test facility inrnNorway. This was done in a Joint Industry Project with Statoil as operator and Chevron, Petrobras, Total,rnand FMC Technologies as participants. The tests were performed with realistic fluids – 59° APIrncondensate and 25° API crude, recombined with natural gas – and at realistic pressure conditions, fromrn25 to 90 bar, with and without inlet slug flow. The separation requirements for the CompactSep systemrnwere a liquid output with gas volume fraction GVF < 0.1 and gas output with gas volume fraction GVFrn> 0.995 downstream the separator system. The pressure drop limits were 2 bar (soft target) and 5 bar (hardrnlimit). Separate and stricter requirements were set for the system’s individual separator components.rnThe main results were: a wide operating range where the performance requirements were fulfilled, 99%rnto 99.9% separation efficiency, gas qualities (GVF) between 0.995 and 0.999, and liquid qualities (GVF)rnbetween 0.02 and 0.1. The operational boundaries were challenged to determine the onset of liquid carryrnover and gas carry under. The actual operating range exceeded the design and performance predictions.rnThe system handled slugging and start-up scenarios. The control system stabilized the process withrnrelatively slow control valves.rnThe work developed and qualified an inline separator system with full turndown and slug handlingrncapability. Qualification was performed at a wide range of realistic conditions and with high qualityrnreference and performance measurements. Comparison of CompactSep and conventional subsea separationrnstations shows significant cost and weight reductions for the compact solution. What can be donernsubsea can be done topside. The CompactSep separator is a viable alternative to conventional vessels forrntopside applications where size and weight must be limited.
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