The FPSO Espirito Santo, located offshore Brazil in the Parque das Conchas (BC-10) field, is the world's first turret moored FPSO to use steel risers for fluid transfer. The FPSO is moored in a water depth of 1, 780 meters, and the internal turret incorporates a total of 21 riser and umbilical slots. The steel risers, which are in a Lazy Wave configuration, were pulled into the turret through inclined I-tubes. Clamps at the top of the I-tubes retain the risers, thus transferring axial loads from the risers to the turret. A clamp casting welded at the bottom of the I-tubes houses a stopper arrangement designed to transfer shear forces and moments from the risers to the turret. The FPSO began oil production in July 2009, and now has over 4 year's optional experience. During this period, inspection of the riser system and the associated flex-joint has confirmed the integrity of the design, giving further confidence in the use of steel risers in turret moored systems. This paper summarizes the basis for selecting steel risers for the development, how the risers and umbilicals interface with the turret, and the impact of the riser choice on the turret design. The in-service inspection of the riser system is described and the results reported.

The development of floating offshore wind farms requires the parallel development of suitable floaters to support the wind turbines. These floaters must be economic and must also exhibit good motion characteristics to limit the accelerations and inclinations imposed on the turbines during operation. This paper reviews the required characteristics of these floaters, addressing the requirements of fabrication, turbine integration, tow to site, and offshore installation, as well as the required behavior of the floater once installed. The benefits of an integrated design approach considering all of the above is demonstrated, and consideration is given to the industrialization of the production process for large numbers of floaters for full-scale wind farms.Based upon this review of requirements, an innovative light weight structural solution incorporating tensioned mooring legs has been developed as an economic solution for the floater. The modularity of the design facilitates construction, and offshore installation can be accomplished using standard anchor handling vessel (AHV) means. The floater design exhibits low turbine inclinations and low accelerations due to a combination of its mooring arrangement and its high degree of transparency to waves, which reduces fatigue loads and maintenance issues on the turbine.The floater behavior during towing to site and in the installed condition is described, and key performance characteristics are reported based on analytical simulations and model tests results conducted at 1:40 scale.The paper seeks to clarify the key factors to be considered in developing a floater to support a wind turbine, and to propose a solution that achieves good motion characteristics whilst satisfying the economic constraints of wind farm development.

This paper reviews the issues associated with mooring a ship shaped Floating Production Unit (FPU) in arctic conditions, and presents the development of a novel disconnection and reconnection system for such conditions. The mooring systems of FPUs operating in arctic conditions must be disconnectable to allow the FPU to leave the station to avoid collision with icebergs, or to avoid overloading the mooring legs due to sea ice acting on the FPU hull. In the case of sea ice, the FPU may be required to disconnect under much higher loads than the non-arctic disconnectable systems in operation today. A recent study for the design of an arctic mooring system identified a number of key developments that are required before such systems could be deployed. The disconnection system is a safety critical element, and requires high reliability and redundancy to ensure the FPU can always rapidly disconnect from its mooring when required. In addition, the large number of risers that may be installed for these large field developments, combined with the significant suspended weight resulting from the high capacity mooring system, leads to large buoyancy requirement for the buoy which must support the risers and mooring system when disconnected from the vessel. As a consequence the analysis of the reconnection process must account for the coupled behaviour of the large buoy body, the mooring system, and the risers and umbilicals. Such analysis has shown that using conventional disconnectable turret technology, the large buoy size coupled with the requirement to reconnect in heavy sea states, can readily generate snatch loads that would break the pull-in winch wire. In response to the above, this paper presents two significant advances in disconnectable mooring technology. The first is the development of a new locking system to connect the buoy to the turret, which has been qualified at full scale. The second concerns the design of a new pull-in arrangement that eliminates the risk of snatch loads even in sea states in excess of 3m Hs. The system robustness has been demonstrated through model testing.

There is renewed interest in the oil and gas industry in standardisation as a mechanism for cost reduction, driven by the present low oil price and a search for efficiencies in project execution. However, the implementation of any approach to standardisation requires clarity about the objectives, benefits, and compromises that are required. This paper reviews the different approaches to standardisation that can be considered for FPSOs, examines historical examples of standardisation, and the degree to which these examples have been successful. In particular, the paper addresses the extent to which design replication is possible, and the impacts of field conditions, regional regulatory framework, and client specifications on standardisation. Based on lessons learnt from the industry, together with in-house experience of FPSO design and operation, the paper will provide guidance on the extent to which standardisation can be achieved, the areas in which it can be applied, and the potential obstacles to its successful implementation.

SBM Offshore; Svein Haaheim, Shell Brasil Petroleo; and Eric Martineau, SBM OffshoreThe centrally located FPSO facility is the Espirito Santo. The BC-10 joint venture charters the FPSO facility from SBM Offshore jointly with MISC under a long-term lease and operating contract.A unique feature of the BC-10 development is the use of steel lazy-wave risers (SLWRs) in conjunction with an internal turretmooring system. This is the first use of SLWRs in the industry, and the first time a steel-riser system of any configuration has been used with an internal turret-mooring system. After more than 5 years of operational experience, the integrity of the turret and riser system has been demonstrated in field conditions. The intent of this paper is to describe the impact of the use of SLWRs on the turretmooring system, and to report the in-service inspections carried out to verify the ongoing integrity of the riser system. Mooring-System SelectionTurret-moored floating production, storage, and offloading (FPSO) vessels and spread-moored FPSO vessels are both operating offshore Brazil, but the spread-moored systems rely on shuttle tankers with dynamic positioning (DP) to ensure sufficient availability of SummaryThe floating production, storage, and offloading (FPSO) facility Espirito Santo, located offshore Brazil in the Parque das Conchas (BC-10) field, is the world's first turret-moored FPSO facility to use steel risers for fluid transfer. The FPSO facility is moored in a water depth of 1780 m, and the internal turret incorporates a total of 21 riser and umbilical slots. The steel risers, which are in a lazywave configuration, were pulled into the turret through inclined I-tubes. Clamps at the top of the I-tubes retain the risers, thus transferring axial loads from the risers to the turret. A clamp casting welded at the bottom of the I-tubes houses a stopper arrangement designed to transfer shear forces and moments from the risers to the turret.The FPSO facility began oil production in July 2009, and now has more than 5 years of operational experience. During this period, inspection of the riser system and the associated flex joint has confirmed the integrity of the design, giving further confidence in the use of steel risers in turret-moored systems.This paper summarizes the basis for selecting steel risers for the development, how the risers and umbilicals interface with the turret, and the impact of the riser choice on the turret design. The in-service inspection of the riser system is described, and the results are reported.