SAIPEM Novel Hybrid Riser: RCS

Abstract

As the offshore industry continues to progress developments in deep and ultra-deep water locations, in many large EPCI contracts (Engineering, Procurement, construction and Installation) the considered or preferred riser system solutions are steel catenary risers (SCRs) or lazy wave (LW) SCRs. The criticality of SCR technology continues to require detailed assessment of technology risks for each specific development, even where design conditions may not appear to vary significantly from previous developments. The potential for increased water depth, severity/complexity of environmental loading, a wider range of vessel typology and with ongoing integrity monitoring & maintenance feedback, it is clear that there is an increasing risk that SCR will exceed the technological limits for near future developments. Looking forward, there is a primary need to manage the risks of this elegant & commercially attractive riser solution by ensuring the margin between the expected fatigue /extreme loading and the current technological limits of metallic material/welding, top connection and non-metallic components. In this context, and through a fully integrated approach to riser technology, SAIPEM has conceived and matured families of hybrid riser systems based on field proven technology. One of these families is the novel hybrid riser family, specifically conceived to extend the application of SCR & LWSCR in a cost effective way as well as offering certain additional improvements. The basic solution is the RCS (Novel Hybrid Riser with Top Connecting Arm & Shallow Water Jumper); a balanced cost /risk hybrid riser solution to compete with SCR & LWSCR. RCS offers consistent improvements and is adaptable to the major vessel typologies, from semi-subs to disconnectable turret moored FPSOs. The RCS comprises Top Connecting Arm (TCA), Riser Top Assembly (RTA) and Tension Restrained Jumper (TRJ) or simple short/long catenary jumper (SCJ), and is connected to the vessel by means of a deepwater type mooring connector. RCS+ is a further evolution of RCS incorporating adjustable length TCA. RCS+ Heave Motion Damper (HMD) is a future evolution of RCS, and is described separately. The RCS is an example of the application of an industrial model that includes an integrated engineering and execution expertise to achieve future cost effective solutions.