Double Catenary Offloading Lines for Deepwater Fields

摘要

The use of non-weathervaning floating production units isrnfound feasible for fields in the deep waters of West Africa.rnThe lack of pipeline infrastructure in these remote areasrnrequires export of produced fluid from an offloading system.rnThe transfer of product from the production vessel tornoffloading buoy is carried out by large diameter suspendedrnflexible flow-lines. The flow-lines are configured in a doublernwave shape, “W” concept, by introducing distributedrnbuoyancy along the middle section of the lines.rnThe paper presents an alternative concept, a naturallyrnsuspended double catenary (“U” configuration) rigid steelrnflow line. A preliminary, but comprehensive, study wasrnconducted, which considered strength and fatiguernperformance, technical merits and demerits, economic gainsrnand losses, and safety and reliability concerns between the twornconcepts. The results of the study confirmed the feasibility andrnpotential savings of the proposed “U” concept.