2 executive summary
The report shows that the Oil & Gas Industries have developed a large choice of different platforms and floater concepts which are readily available for deepwater (500m-1500m) and ultra-deepwater (1500m-3000m) offshore field development.
The FPU concept selection will greatly depend on the retained ‘Field Architecture’ (Ref.[21] ) There are approximately one (1) fixed platform and six (6) FPU concepts which can be (conveniently) gathered in two (2) families, e.g. surface ‘dry’ trees or subsea completed ‘wet’ trees, as follows:
Dry Tree Supports:
CompliantTower (up to 500m water depth limitations).
TLP or Tension Leg Platform (up to 1500m water depth perceived limitations).
SPAR and EDP or Extended Draft Platform (up to 3000m water depth).
Wet Tree Supports:
Semi-Submersible Floater (up to 3000m water depth).
Floating Production Storage and Offloading (FPSO) vessels, Floating Production Unit (FPU) vessels, Floating Production Storage and Offloading of Liquefied Natural Gas (FLNG) vessels.
Buoy shape floater, e.g. SSP (Sevan Stabilised Platform).
Deep Draft Semi-Submersibles, e.g. EDP (up to 3000m water depth).
TLPs.
SPARs.
Above floating facilities are to be moored at the field locations within a specified watch circle (offset, orbital motion) under normal operating load and extreme storm load conditions. A variety of mooring system configurations (spread, turret, SPM), mooring lines (steel wires, synthetic ropes) and configurations (catenary, taut, semi-taut) as well as anchor systems (fluke, vertical loaded anchor, suction caisson, pile, Torpedo anchor) have been developed for the station keeping of these FPUs.
In the coming years, there will be a growing demand for floating facilities in ultra deep waters (greater than 2 000meters) and one of the design issues will be the selection of the most cost-efficient station keeping system for the specified water depth and environmental conditions.
