MacGregor’s Plimsoll winch used for Single Buoy Moorings’ (SBM)Frade FPSO will be moored by an internal turret accommodating 33 risers. The moorings and risers will be handled by a Plimsoll winch supplied as part of an equipment package by MacGregor’s Offshore division.
The package of Plimsoll equipment supplied by MacGregor also includes a 45-metric ton (50-ton) auxiliary winch, electro-hydraulic power pack, local control station, and rotary platform.
The Plimsoll main winch will tension mooring chains and pull in the pipeline risers that transfer well fluids from the seabed to the surface. It features a single main plain-cored drum with two storage compartments. Each of four variable-speed, low-torque hydraulic piston motors drives through an epicyclic reduction gearbox and on to a final drive guarded spur reduction gearset.
Enclosed plate type brakes mounted between the hydraulic motors and reduction gearboxes release hydraulically and are spring applied to fail-safe to ‘on’. Counterbalance valves are fitted into the hydraulic circuit to assist with controlled lowering on the winch.
The Plimsoll auxiliary winch has a stall pull at top layer of 45 metric tons (50 tons), a duty pull at top layer of 40 metric tons (44 tons), and a brake holding load of 55 metric tons (61 tons) at top layer.
The power pack is designed to operate both winches simultaneously for wire tensioning, and has an estimated maximum noise level of 90 dB.
The stainless steel local control station is mounted on the rotary platform in a position to suit the operator. Monitoring equipment includes line tension indicator with overload alarm, wire length measuring system, and automatic stop when the winch reaches the last four turns on the drum.
The rotary platform is designed to carry the main riser winch, hydraulic power unit and control stand. The platform is mounted on wheels that run on deck-mounted rails.
The Frade field is Chevron’s first oilfield development project in Brazil. The field is located in the Campos basin in a water depth of 1,000 m (3,281 ft), about 75 mi (121 km) off of Rio de Janeiro. It is expected to begin production in late 2008 or early 2009.
TheFrade FPSO is fitted with topsides for the production of 100,000 b/d of oil; treatment and compression of 106 MMcf/d of gas; and treatment and injection of 150,000 b/d of water.
Intervention vessel package
MacGREGOR also supplies its Hydramarine system for heavy subsea loads on intervention vessels, and its Hydramarine package for a new inspection, maintenance, and repair (IRM) vessel, which includes a 60-metric ton (66-ton) module handling system. This system is designed for applications when a crane is unable to guide a load as needed.
The system designed forEdda Fauna is fully integrated where the load carrying structures are part of the vessel structure and even skid beams are integrated into the vessel’s deck. The advantages include more space and better safety. The entire tower system is in this case inside a large, heated work hangar so the system is well suited for arctic operations.
The Skipsteknisk-designed ST255L IMR vessel,Edda Fauna was delivered from Aker Yards Brattvåg facility to Norwegian operator Østensjø Rederi in February. The vessel is on long-term chartered by IMR specialist DeepOcean ASA to work for Statoil in the North Sea.
Designed for operation in northern waters and with a high focus on maneuverability and station-keeping capabilities,Edda Fauna can work on:
- ROT (remotely operated tool) operations using its module handling system
- Inspection and ROV (remotely operated vehicle) operations
- Light construction work
- Scale squeeze and pumping operations
- RFO (ready for operation) work.
Edda Fauna can handle modules of up to 66 tons with dimensions of 6 m x 6 m x 8 m (20 ft x 20 ft x 26 ft) to a maximum depth of 2,000 m (6,562 ft) in sea states with significant wave heights to 5 m (16 ft). The system consists of a rail skid arrangement on the main deck for horizontal transportation of loads, and a cursor system, liftline, and guideline winches for vertical transportation through the ship’s moonpools. Horizontal movement of modules is achieved by sliding pallets which are moved by hydraulic tractors or “pushers.” The module handling system has four different types of pallets with their own tractors: a 60-ton (54-metric ton) pallet, two different sizes of 30-ton (27-metric ton) pallets, and a 3-ton (2.7-metric ton)/10-m (33-ft) crane pallet.
