Energy major Shell has temporarily suspended shipments from its huge floating LNG (FLNG) unit Prelude off northwest Australia.

Shell said its shipping schedule has been "proactively adjusted", according to Bloomberg.

The major is working to restore full production after an electrical trip on the massive floater halted liquids production at the start of this month.

Sources who follow Prelude closely told TradeWinds that the main electrical generator on Prelude tripped and then a back-up system followed suit.

They said Shell then opted to use the incident to do a full evacuation of personnel from the floater, taking somewhere between 130 to 150 personnel to a designated stand-off area upwind of the unit.

Prelude FLNG snapshot
  • Vessel type: Floating LNG unit
  • LNG production capacity: 3.6 mtpa
  • Condensate production capacity: 1.3 mtpa
  • LPG production capacity: 0.4 mtpa
  • Builder: Samsung Heavy Industries
  • Topsides: Technip
  • Overall length: 488 metres
  • Beam: 74 metres

One source said that while cargo exports were planned from Prelude, these have been suspended while Shell does further checks to ensure the electrical issues have been solved.

He commented that that the condensers and compressors on the FLNG experience large electrical spikes and that cabling onboard is complex, making repairs challenging.

Speaking in November, Shell said Prelude had exported had delivered eight LNG cargoes since its start-up in June, along with condensate and LPG shipments.

The 600,000-tonne Prelude FLNG unit, which is the largest floating structure ever built, shipped its first cargo on the 173,400-cbm Valencia Knutsen (built 2010) and offloaded its initial condensate shipment earlier in the year.

Prelude, which has capacity to produce 3.6m tonnes per annum of LNG, is located about 475 kilometres (295 miles) north-northeast of Broome in Western Australia.

The unit's remote location makes access and repairs more challenging.

Prelude, which was dogged by delays in its start-up, is supported from Shell's office in Perth and is served by sea from a supply base in Darwin, which is a two-day journey for a platform supply vessel.

Personnel working on the unit need to be flown in from Broome, where Shell has built a new logistics base.

Shell has also built a helicopter base at a township some 45 minutes by air from Broome, where craft will be refuelled before heading offshore to the FLNG unit.

The major controls a 67.5% stake in the Prelude FLNG project, with Japan’s Inpex holding 17.5%, Korean state-utility Kogas owning 10% and CPC of Taiwan 5%.