THE LIFETIME DYNAMICS OF A DEEP-WATER RISER DESIGN

This paper discusses the dynamics of a hybrid production riser designe d for a water depth of 1500 m in the harsh environment west of Shetlan d where one of the main design drivers is offshore installation time. To minimise installation time, a free standing riser was developed com prising a carrier pipe, top and bottom taper sections and an integral subsurface buoy connected by flexibles to the moored FPSO. The paper d iscusses the different dynamic characteristics of the structure during tow out, upending, connection and when installed. The simulation meth ods used, the design drivers, design compromises and parameter sensiti vities are also discussed. It is concluded from extensive dynamic anal ysis and structural design that the proposed design is feasible and th e estimated on-site installation time is 2-3 weeks. (C) 1998 Elsevier Science Ltd. All rights reserved.