Technip-Coflexip has developed a new installation concept called the "Jack-Deck" (Patent Pending - Patent N° FR 01.16835 registered on 24/12/2001) which enables installation of FPSO Topsides on to a FPSO Hull Deck in one or two "Integrated Modules" with weights of up to 19800T each (See Figure 1). This installation method facilitates extensive pre-commissioning and commissioning of the "Integrated Modules" at their Construction Yard. It considerably reduces the onshore hook-up and integration work required on top of the FPSO Hull Deck. Consequently the overall FPSO Construction Schedule and Cost are significantly reduced.
This paper describes the "Jack-Deck" installation method and discusses the consequences on Topsides layout and structural design. It also highlights the main benefits of the system.
With the discovery of new Oil & Gas fields located in deep waters and the recent development of subsea completions and flexible risers, FPSO's have become more and more commercially attractive. They enable development of fields with little infrastructure for oil export and offer not only a low installation cost, but also a low decommissioning cost at the end of field life. They offer the advantage of being readily re-deployed on other fields. All these points have expanded the FPSO market and encouraged Oil & Gas Companies to invest in this type of production system. Many FPSO's have already been successfully installed in West Africa and other parts of the world. Several others are under construction, and many proposals for future FPSO Development Projects are in preparation with early installation objectives.
The traditional method for constructing an FPSO is to build the hull in a Shipyard and the Topsides in a separate Construction Yard. The topsides are split into several modules, typically 8 to 14 with weights ranging from 1000T up to 3000T. The modules and / or the hull are then transported to the integration yard where the modules are lifted and installed in place on top of the FPSO Hull Deck.
Fig 1: "Jack Deck" installation concept (AVAILABLE IN FULL PAPER)
Due to the large number of modules, the lifting and installation phase can extent for several weeks and the integration, pre-commissioning and commissioning work may have to be interrupted to allow the installation of the modules as they arrive at the integration site.
This traditional method has been imposed on FPSO Contractors by the high elevation of the FPSO hull deck above the quay, which can reach up to 30m, and by the relatively small lifting capacities of most of the Construction Yards, which are generally limited to 3000T. Selecting yards with higher lifting capabilities would reduce competition and further increase the fabrication and integration costs. In any case, the lifting capabilities of these particular yards are still limited to around 7000T, which is low in comparison with the "Jack Deck" 's installation capacity.
