New video update shows the securing of the 16 mooring chains holding the 500m-long facility in place.
It is shaping up to be a big couple of weeks in Australia’s Browse Basin.
Icthys’ Venturer floating production, storage and offloading (FPSO) facility arrived at its permanent mooring in mid-August (See: September issue of InnovOil). The arrival of the Venturer followed just weeks after the maiden voyage of Royal Dutch Shell’s rival Prelude floating LNG (FLNG) facility to its new home, around 475 km off the coast of Broome in Western Australia. In mid-September, the company confirmed that it had been successfully secured to its mooring, where it will remain for its 25-year operational assignment, around half of its total expected lifetime. Shell operates the project with a 67.5% stake, alongside Inpex (17.5%), Korea’s KOGAS(10%) and Taiwan’s CPC (5%).
At 488m long and requiring around US$12.6 billion in investment, Prelude puts the “mega” back into “megaproject.” It is the largest offshore facility ever constructed, displacing 600,000 tonnes of water, and built to withstand the tropical cyclones – up to category five – and rough seas of the NW Shelf.
Critical to this is the facility’s gigantic mooring system, about which Shell explained more in a recent video update. This video covers the securing of number eight of the sixteen mooring chains to the facility’s turret, also one of the largest ever built. 17 km of chains were fabricated by Spain’s Vicinay Cadenas, amounting to a total of around 25,000 links. These were then aligned on the seabed, with the commissioning team on board pulling in each to within an accuracy of one or two links, pre-determined prior to the operation.
The mooring was overseen by TechnipFMC, which has been tasked with project management, EPC and commissioning on the project, using its Deep Orient vessel.
Innovation has been critical to the success of the project. All told, according to Lloyd’s Register the project has already generated over 150 patents.
On board, the processing of gas and condensate occurs in modules that occupy an area approximately one quarter of the size of a typical onshore LNG plant. Shell’s Dual Mixed Refrigerant (DMR) process – originally developed to enable liquefaction at the Sakhalin LNG project, where temperatures can range between +/-25°C – is used to liquefy the gas. Among other innovations, the system also uses waste heat from the process as a heat source for the gas treatment unit, to improve efficiency.
LNG and LPG produced at Prelude will then be offloaded in a side-by-side vessel arrangement, using specially designed cryogenic loading arms. Condensate will be offloaded from the rear of the facility using a floating hose. In total, the company expects production to reach a minimum of 5.3 million tpy of liquids, of which 3.6 million tonnes will be LNG, 1.3 million tonnes will be condensate and 0.4 million tonnes LPG.
While mooring looks to be on schedule, and hook-up and commissioning are set to continue into 2018, the company has not yet provided an official start-up date. Its current statement is that it “expects to see cash flow from the project during 2018,” with outside estimations suggesting this may begin sometime between April and September next year.