The paper describes some of the issues the FPSO industry has faced in recent years, noting that during this time the oil industry was highly focused on ship-shaped hull forms for the floating production market. The main drivers being the availability of conversion candidate tankers together with construction yard space.
In recent years the position has changed as candidate tanker availability is at a premium. Also the LNG industry has attracted substantial interest in the shipbuilding industry taking up FPSO fabrication slots in the shipyards. Shipyards are forecasting protracted deliveries for FPSOs especially if new build construction is a consideration.
A constrained tanker market coupled with the constant drive to improve cost and project delivery schedules have driven industry contractors to seek alternative, innovative approaches to ship-shape hull forms.
This has led to the development of the Round Ship Satellite Services Platform (SSP). This concept combines many of the desired characteristics of existing floating production solutions into a relatively inexpensive easily fabricated and installable unit for future deepwater developments.
The paper reviews the SSP concept development and contrasts its suitability with the conventional tanker solutions for floating production.
Operators are often faced with the interesting project challenges of new build construction verses tanker conversion for their offshore projects. The major issue with conversion tends to be centered on tanker availability at the desired time plus classification issues with the quality of the hull selection.
Conversely, new builds must deal with suitable yard availability together with extended schedules. Whether the operator contracts to have a new build vessel, or chooses to convert a tanker, there are a number of issues that must be faced. These include technical and cost challenges, such as the turret, deliverable hull forms, swivel path, and storage capacity. Another set of important features or issues includes vessel motions, fatigue loading, process performance, vessel configuration, single hull versus double hull, resistance to green water, and compliance with local rules and regulations.
The amount of steel and tank compartment spacing is often a function of maritime regulations. The double hull requirements, as well as the additional strengthening of the tank top can have a significant cost impact. Conventional tanker FPSOs has sensitive loading and offloading requirements in managing the hogging and sagging.
One of the greatest advantages of the SSP as an alternative solution to the FPSOs is that it can be constructed for purchase or lease faster than a tanker based FPSO project. This presents opportunities for early production.
The SSP has many desirable volume and structural aspects, such as double hull separation, no areas of high stress intensity, a large deck space, and limited ballast requirements during loading and offloading. Due to the large buoyancy afforded by the efficient shape, significant fixed ballast can be accommodated to shift the center of gravity below the waterline. The length of the center column assembly and the magnitude of the fixed ballast provide the opportunity to also modify the roll radius of gyration.
