GOLETA, California, U.S.A., April 22, 2002
Bardex Corporation of Goleta, California has received a contract from BP America Production Company of Houston, Texas to supply the Linear Chain Jack Mooring System for the BP Thunder Horse deepwater development project in the Gulf of Mexico. The mooring equipment will be used on the world’s largest steel production, drilling and quarters (PDQ) semi-submersible, which has been designed by GVA Consultants of Sweden and Mustang Engineering of Houston, Texas. Thunder Horse lies in Mississippi Canyon block 778 in over 6000 ft of water approximately 150 miles southeast of New Orleans.
The semi-submersible design consists of a rectangular pontoon and four columns, with mainly modularized production facilities and the integrated drilling facilities, as well as the living quarters, located in and on the upper hull. Mooring of the floating offshore installation will be accomplished via a taut-leg 16-point mooring system with suction anchors. The mooring lines will have a chain-wire-chain configuration and will use studless link mooring chain at the surface.
The Bardex mooring system will consist of 16 hydraulically actuated 6800 kN (1530 kip) stall capacity Linear Chain Jack assemblies with chain stoppers and turndown sheave arranged in four groups (four at each corner of the rig), four Hydraulic Power Units (one at each corner), a programmable logic controller assembly (PLC), and four local Control Stations in control cabins (one at each corner). The mooring system will be an active system capable of maneuvering the PDQ unit over the subsea wells.
The Bardex Linear Chain Jack assemblies will be used to haul in or pay out each mooring chain in a series of coordinated operations–consisting of latching, jacking and unlatching–and to hold the mooring chains during idle periods of operation. Being a true linear device, the Bardex chain jack lifts the chain in a straight line throughout the lifting sequence. There are no induced link bending stresses and interlink wear inherent when jacking the chain and simultaneously bending it around a shoe or wildcat. The latches in Bardex linear chain jack assemblies are hydraulically actuated and mechanically interlocked so that one latch set cannot be disengaged unless the other latch set is engaged. Transfer of the load onto the latches is made only after the latches are engaged. The latches contain machined contoured pockets to cradle the chain and maximize the chain contact surface to reduce chain deformation and wear.
The system’s PLC will contain all of the control logic necessary for remote automatic operation and will monitor chain jack cylinder position, latch and chain load status as well as chain stopper load and line-out status. The Bardex control system also will provide the capability of operating the chain jacks in manual mode. The system also will be linked to the central control station located in the process control room on the semi-submersible to allow monitoring and operating the functions of chain pay-out/haul-in, jacking speed, static and dynamic tension, hydraulic pressure, hydraulic oil temperature, and cooling water temperature.
Delivery of the mooring system is scheduled for the fourth quarter of 2002. Daewoo Shipbuilding & Marine Engineering is building the semi-submersible at its fabrication yard in Okpo, Korea. Initial production from the Thunder Horse project is expected by early 2005.