Projects, Facilities and Construction Committee: The Case for the Round Ship
An FPSO is a moored ship that produces oil from wells drilled into a reservoir beneath the ocean bed, stores the oil and offloads it to shuttle tankers for transport to refineries. Such FPSOs have been used increasingly in South America, Asia and West Africa. They have not been used so far in the Gulf of Mexico, due mainly to its existing pipeline network and practical concerns on seasonal extreme weather conditions.
With increasingly deeper water being encountered in the GoM the existing pipeline network is much less of a consideration and the use of FPSOs is becoming more financially attractive. The first FPSO destined to be used in the GoM will begin production for Petrobras in 2009 and will utilize a conventional turret buoy allowing wind directed rotation and the ability to disconnect in the event of extreme weather. This design arrangement is now being challenged by concepts which will allow FPSOs to remain on station in such weather extremes.
This presentation focuses on two designs which challenge the traditional turret buoy design in addressing the ability for the FPSO to remain on station. Two design concepts are presented for discussion. One design now has a single unit in operation, the Sevan Marine Piranema offshore Brazil, and the other design is under the later stages of development.
Sevan Marine ASA is listed on Oslo Børs (ticker SEVAN) and is specializing in building, owning and operating floating units for offshore applications. The Company has developed a cylinder shaped platform type, suitable for applications in all offshore environments. Presently Sevan Marine is focusing on two application types for its cylinder platform: floating production and drilling. The Company has, since its origin, focused its business on the development of a new cylinder shaped platform type for storage and production of hydrocarbons in deep and shallow waters (FPSO). The platform is designed to operate in all types of offshore conditions. The main competitive advantage claimed by Sevan Marine is the Sevan platform combines internal oil storage capacity and ability to carry high topside weights with a low construction cost compared to other FPSOs. The Sevan platform is an alternative to ship based production and storage solutions as well as semisubmersibles, TLPs and Spar platforms. The platform is suitable for use in all offshore markets including harsh environment areas and on both marginal and large field developments, due to its flexible design and favorable motion characteristics. Currently, the Sevan platform has been used for production and drilling applications. Due to its versatility, the Sevan design may also be used in connection with applications such as accommodation and various gas applications. Going forward, the Company will evaluate the potential for such complementary uses of the Sevan Technology.
OPE Engineering & Project Management Services claims their patented SSP® design provides excellent motion characteristics while moored offshore. The SSP® does not require weather-vaning like an FPSO, and OPE states it has excellent motions in complex seas where swells, current, and wind may be from different quadrants. OPE states the round shape hull form design of the SSP® is inherently stable and immune from 'free surface' effects, is hydro-dynamically smooth from the aspects of storm waves and does not suffer from wave slam and wave run-up. OPE claims the freeboard offered by the SSP® eliminates green water on the deck and further states taht in addition to the above design features, one of the most important factors is the ratio of payload to vessel steel weight that directly translates into the hull fabrication cost. OPE claims that by design, the SSP® can achieve significantly high payload ratios as compared to conventional floating production units such as semi-submersibles, TLPs and Spars. For larger SSP® units for crude storage application, OPE states the SSP® can provide even higher payload ratios than the ship-shaped FPSO units.
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