The scope of this Environmental Plan includes FLNG arrival on-site, offshore works, hook-up and commissioning (HUC), start-up and the operate phase. This EP includes the FLNG facility itself, installation vessels and support vessels contracted for the offshore works and HUC activities, tug boats pulling the FLNG into Australian waters, and the support, supply, and in-field vessels required during the operate phase of the facility. The EP also includes transit of the support vessels and helicopter providing support to the FLNG operations and well intervention activities using a light well intervention vessel.
The Prelude FLNG Project is in WA-44-L and WA-2-IL, in Commonwealth marine waters, 200km offshore northwest Australia and 460km north-north east of Broome, in 237m from Mean Sea Level (MSL) water depth. The Prelude FLNG facility is planned to be towed from South Korea where it was constructed and partially commissioned. The installation, hook-up and commissioning is planned upon arrival of the FLNG, from then the facility will be ready for start-up (RFSU). The Prelude FLNG facility is designed to stay on location and operate for 25 years.
The Prelude FLNG Project comprises of the Prelude FLNG and subsea equipment including production wells, xmas trees, manifolds, flowlines, riser base manifold, flexible risers and an umbilical and subsea distribution hardware providing hydraulics, power, communications and chemical services to the subsea wells and subsea manifolds. The Prelude FLNG development has one drill centre with two 6-slot manifolds, a base case 7 production wells located 3km south of the Prelude FLNG. The Prelude FLNG is connected to the gas reservoir via 12” flowlines and flexible risers routed to the turret.
The FLNG facility itself is approximately 488m long and 74m wide, and moored at the gas field location during the period of production. It is permanently moored during the operations phase, remaining on station during cyclones. The FLNG facility has been designed to withstand a 1 in 10,000-year weather event and with a field life of 25 years. The FLNG facility includes LNG, LPG and condensate storage as well as facilities for exporting these products to carriers. All reservoir, subsea control, processing, storage and loading functions are operated from the FLNG facility.
Infield support vessels will support the FLNG in station keeping during offloading of products, as well as provide Safety, Security and Emergency response support. Supply vessels will bring in materials and supplies into the facility and bring out wastes and supplies to and from Darwin Onshore Supply Base. Crew change will be via helicopter.