The Satellite Service Platform (SSP) hull design originated in Houston in the late 1990s and was the brain child of Richard Haun, one of the co-founders of OPE, a Houston-based subsea engineering company.

Not realizing the full potential of the early SSP design and focusing on core subsea engineering business activity, OPE relegated the SSP to the back office for several years. Changes in the direction of the floating production market rekindled the idea, though, and the original bowl-shaped hull was modified to more closely resemble the design of the SSP Base today. This early start does, however, make the SSP one of the first circular hulls specifically designed for use in the floating production market.

(Editor's note: A circular design from Sevan Marine ASA has been used for three FPSOs now in operation in Brazil and the North Sea.)

A key distinguishing feature – and one of the main advantages of circular floating production hulls compared to more traditional ship-shape hulls – is that they do not need to weathervane, which effectively eliminates the need for a costly turret mooring system and complex swivel assemblies.

In 2009 the SSP Base hull design was modified with the addition of a heave modulation skirt, and the SSP Plus was born. The skirt, placed at keel level, greatly increased the natural period of heave with the subsequent reduction in heave modulation, making the hull yet more suitable for deployment in harsh environments.

Tank-tested to the extreme

The SSP Plus has been extensively tank-tested in the most extreme environmental conditions, with the results confirming that the hull design is profoundly stable in all conditions from the benign environments of West Africa to the harshest Gulf of Mexico post-Katrina storm conditions. Its motion characteristics allow it to be deployed as an FPSO vessel, which could support either wet or dry tree development solutions, and also the use of the hull as a drilling rig.

It has received approval in principle from ABS and is being considered by a number of operators as part of their tool box strategies for field developments. Multiple inquiries and studies performed for a variety of E&P companies have confirmed the competitiveness of the SSP Plus design, and the company is actively engaged in dialog with these potential clients.

The circular hull form is rapidly becoming an integral part of an operator’s toolbox solution for E&P projects around the world. A clear example is that in 2012, the US Department of Energy’s Research Partnership to Secure Energy for America awarded a FEED contract to Doris Engineering and SSP to investigate the use of circular floating production facilities.

By early 2012 the SSP designs had matured to the ready-to-build stage, and in December 2012, in partnership with Jiangsu Yangzijiang Offshore Engineering Co. Ltd. (the offshore fabrication division of the Yangzijiang Shipbuilding group), SSP began detailed design engineering to be followed by construction engineering for the first unit. This is scheduled for delivery in 2Q 2015.

SSP Offshore already has entered into regional strategic alliances in Brazil, Asia, and West Africa.

Technical challenges

SSP has followed a “stage gate” approach in the development of its technology to minimize rework, control costs, and meet the development schedule.

With any new hull form design, the biggest sales challenges always come down to safety and cost. Being able to prove to potential users that the motion characteristics of the hull are what they are claimed to be (i.e. the unit is inherently stable and safe, combined with cost-competitive fabrication) has been the SSP team’s focus from the start.

With this in mind, between 2007 and 2011 both the SSP Base and the SSP Plus models underwent concept design followed by advanced basic design engineering in consultation with a number of well-known independent consulting companies, which included numerical hydrodynamic validations by independent naval architecture companies.

This intensive design engineering period also included extensive global performance tank tests for both hull designs together with testing of the SSP-patented dynamic hawser offloading system. All tank tests were underwritten and supervised by the MARIN Institute of the Netherlands.

On the cost front, over the past two years fabrication requests for quotes (RFQs) have been issued to more than 25 shipyards, resulting in the compilation of extensive fabrication cost data. Late last year, following the issue of a project-specific RFQ (and the subsequent receipt of hull fabrication bids), a letter of intent was executed between SSP Asia Pte. Ltd. and Yangzijiang Offshore Engineering covering the detailed design and construction engineering for the building of the first SSP Plus unit.

Advantages

The SSP designs offer flexible solutions that combine the technical and commercial advantages of optimized production and favorable storage cost per steel ton. The hull has a fully redundant dedicated ballast and cargo pump system for each tank, which is connected to a central ring main system located on the main deck; this feature eliminates the need for a pump room, vertical ventilation shafts, horizontal bulkhead penetrations (for piping), and emergency access shafts.

Another important attribute is the deck payload capacity, which becomes very valuable for deepwater and ultra-deepwater developments. Studies performed for E&P operators confirm that there is value in not being restricted by size and weight of the production modules; this in combination with the ability to integrate topsides at the quayside (which a spar cannot do) further enhances the value proposition of the hull.

Because of the deck space (more than 1.5 acres) and large metacentric height, the SSP Plus can support very large topsides payloads, well in excess of those allowed by physical module size.

In ultra-deepwater provinces, unlike ship-shape FPSOs, the SSP does not need a turret or swivel, and the large diameter of the structure – where risers are brought up through the central moonpool and mooring lines run down the outer hull sides – eliminates any issues with riser/mooring clashes.

Whether buying a newbuild ship-shape floating production hull or an SSP circular hull, the delivery cost comes down to the amount of steel used and structure complexity. The SSP Plus hull design, with 2 MMbbl of storage, costs almost 30% less than a conventional new-build ship-shape FPSO. This factor, combined with the savings recognized by the elimination of a turret and swivel system, make the SSP Plus a competitive floating production solution.