-Newfoundland Offshore Certificate of Fitness Regulations.
-Newfoundland Offshore Petroleum Production & Conservation Regulations.
-Newfoundland Offshore Petroleum Installation Regulations.
-Petroleum Occupational Health & Safety Regulations - Newfoundland.
-Newfoundland Offshore Petroleum Drilling Regulations.
-Newfoundland Offshore Area Petroleum Diving Regulations.
-Canada Shipping Act.
-Offshore Waste Treatment Guidelines.
-Newfoundland Offshore Area Guidelines for Drilling Equipment.
Class Notation
*OI 100AT (1) Floating Production and Oil Storage Installation, for service at Terra Nova field offshore, Newfoundland.
*LMC - LRS inspection of Machinery Installation/Testing
IGS - Inert gas system
Additional notations
PM (T3) - Position Mooring
OIWS - Offshore, In Water Survey
ICC - Computer Control Operations
CCS - Centralised Control Station
Descriptive notes in register
Ice Strengthened
SBT (LR)
Helideck
Vessel Design Development
Background. Brown and Root's Marine Technology Group has carried out the vessel design for Terra Nova. The group has been actively developing marine vehicle designs for floating oil and gas production over a number of years.
BAR FPSO for severe environments include the PV150 standard FPSO, originally developed in 1995 for the Haltenbanken area in the Norwegian Sector of the Northern North Sea. Wind and wave conditions in this area are similar to those on the Grand Banks, and Shawmont Brown and Root identified this design as being the most suitable for Terra Nova, (Fig.3).
Principal dimensions of the FPSO are cited in Table 3.
The arrangement includes a cambered deck with a 0.8 metres camber over a half deck width. The benefits of camber include ice prevention, reduced corrosion, reduction of fire risk from pool fires and rapid drainage of firewater or spray.
Hull Form Design Basis. The Terra Nova FPSO shares the classic design requirements of all ship types - it must provide the weight, space and volume required to carry its payload whilst meeting the needs of stability, structural integrity, seakeeping, propulsion and economy of construction.
The Terra Nova field is subject to violent storms with extreme 100 year wave heights in excess of 30 metres. The conditions are similar to those off Northern Norway or West of Shetland, with the addition of shallow water effects which exacerbate the wave steepness and vessel motions. Vessel motions affect not only the performance and cost of equipment and structures but the efficiency and safety of the crew and the operability of helicopters, deck cranes and offloading equipment. Good vessel motions are therefore one of the primary design drivers.
Crude oil and gas must be processed and oil exported by shuttle tanker, whilst the vessel remains fixed on station by a Thruster Assisted Position Mooring System (TAPMS).
In designing the ship the following requirements have therefore had to be met:
-Crude oil storage capacity.
-Deck space and deck load capacity for mooring, process, offloading and replenishment equipment.
-Good structural layout and hull proportions.
-Minimum hull deflections.
-Access to hull structure and systems for inspection without taking cargo tanks out of service.
-Statutory requirements for stability and strength, including elements of MARPOL.
-Minimum motions in storm conditions.
-Minimum green water on deck.
-Maximum helicopter, supply boat and shuttle tanker operability.
-Minimum environmental loads on moorings and dynamic positioning system.
-Good thruster performance and acceptable resistance characteristics when self-propelled.
These requirements can be mutually contradictory yet a compromise must be achieved that satisfies the Project Design Intent, as a minimum, and strives to meet the additional design targets. The design of the vessel and resultant hull performance represents a complex design exercise, involving a multi-disciplined design team, which delivered a vessel with exceptional performance characteristics.
Some key requirements are discussed below.
Storage Capacity & Tank Arrangement (Double hull & bottom). As stated in the Project Design Intent, the storage capacity is 960,000 bbl, with a maximum offloading rate of 8,000 m3 per hour.
This was achieved by arranging 7 pairs of cargo tanks, divided by a longitudinal watertight bulkhead, such that the number of cargo tanks has been kept to the minimum, consistent with the requirements for damaged stability, avoidance of sloshing loads on the tank structure and the offloading capacity available from the deep well crude oil pumps. The arrangement of crude storage and ballast tanks can be seen (Fig.4).
In order that the size and arrangement of tanks would form a full double skin, meeting MARPOL requirements and allowing full access to the hull structure for inspection, 33 ballast tanks with a ballast capacity of 460,000 bbl were arranged outboard of the crude storage tanks and at the vessel forward and aft sections.
