SMIT wins heavy lift for Bonga FPSONews // January 31, 2003
Beginning late January, Smit will perform a series of lifts at AMEC's Wallsend facility on the River Tyne, UK. This project will require Smit's large floating sheerlegs, Asian Hercules II. This 3,200 tonnes lifting capacity sheerlegs will lift 17 processmodules from delivery barges or the quay, transport them to the FPSO and position them on deck supports.
Asian Hercules II, rigged with a 35 m fly-jib, will use dedicated lifting frames and spreader beams during the lift operations. The work is programmed for a five week period. The modules are : power generation, LACT, port subsea, port process, water flood, starboard subsea, starboard process, flare scrubber, gas sales metering, vapour recovery unit, port field gas compressor, mid field gas compressor, starboard field gas compressor, the compressor control building, lay-down module, flare boom, main piperack and pedestal cranes.
The heaviest lifts are the power generation and starboard process modules at about 2,600 tonnes each. Five of the modules also have large dimensions and weigh between 1,600 tonnes and 2,300 tonnes. To lift the seven big modules, Smit has to use a speciallifting frame. In addition, the main pipe rack - weighing some 370 tonnes - consists of at least seven modules, each requiring an individual lift. Besides the various process modules, Smit will also install a 440 tonnes flare boom with a length of 90m,which will give the Bonga a sailing height of approximately 90m.
For each lift, Asian Hercules II will sail to the lift location and moor. The rigging will then be connected to the module's lifting points and the sheerlegs will slowly increase hook loads incrementally until the load lifts free from the supports. The module will be elevated and transported to the FPSO. Four azimuth thrusters enable Asian Hercules II to manoeuvre accurately into position for each lift and installation. The sheerlegs will then lower the module until it is placed within the positioning guides on the FPSO deck. The module will be lowered fully into position following inspection.
The lifting schedule will be influenced by the limited maneuvering area and tides. These factors will have a particular bearing on the heaviest lifts.
The Bonga FPSO hull was built by Samsung, South Korea. It has a length of 305 m and a beam of 58 m. The hull was towed to the UK by the SmitWijs-operated Global Towing Alliance tug pool. Three tugs - SmitWijs Singapore, the John Ross and the De Da - weremobilised for the tow. On arrival at the River Tyne, SmitWijs moored Bonga FPSO at the AMEC quay.
The Bonga FPSO will be moored offshore Nigeria in the Bonga Field, 120 miles off the coast of the Niger Delta, in a water depth of 1,000 m. The FPSO will have storage capacity for up to two million barrels. Oil will be stored on board and exported via tankers, while gas will be piped to the Nigeria Liquefied Natural Gas plant at Bonny.