A laden LNG carrier has left Shell's Prelude FLNG floating liquefaction facility off northwest Australia.

Eikland Energy data service iGIS/LNG reports that the 173,400-cbm Valencia Knutsen (built 2010) dropped its mooring lines from the huge 600,000-tonne floater today and was guided away from the facility by two tugs.

iGIS/LNG said the ship's draught has been updated to 11.6 metres from a previously registered 9.4 metres, implying the vessel is carrying a full cargo.

Prelude FLNG

Vessel type: Floating LNG unit

LNG production capacity: 3.6 mtpa

Condensate production capacity: 1.3 mtpa

LPG production capacity: 0.4 mtpa

Built: Samsung Heavy Industries

Topsides: Technip

Overall length: 488 metres

Beam: 74 metres

Shareholders: Shell (67.5%), Inpex (17.5%), Kogas (10%) and CPC (5%)

No destination has yet been set for the vessel but the cargo is expected to be discharged in Asia, possibly in South Korea or Japan.

The LNG data analyst showed that over the last seven days Valencia Knutsen made several attempts or trials to come alongside Prelude starting with a first effort on 4 June.

The ship finally moored alongside over the weekend.

Shell said recently that a first export cargo from Prelude FLNG was "imminent".

On Tuesday Shell confirmed the historic cargo shipment from its floater.

The company's integrated gas and new energies director Maarten Wetselaar said: “Today’s first shipment of LNG departed from Prelude FLNG, safely. Everyone involved should be very proud of the work taken to reach this important milestone."

Wetselaar added: “Prelude forms an integral part of our global portfolio and plays an important role in meeting the growing demand for more and cleaner energy for our customers around the world.”

A second LNG carrier, the 170,000-cbm Methane Julia Louise (built 2010), which has been waiting off Darwin for several weeks is also being mentioned by insiders as another vessel which may ship an early cargo from Prelude.

Shell's massive LNG floater is Prelude, which has capacity to produce 3.6-million tonnes per annum of LNG, is located about 475 kilometres (295 miles) north-northeast of Broome in Western Australia and is the largest floating structure ever built.

The unit, which arrived on location almost two years ago, shipped a first condensate cargo earlier this year.

A first LNG export cargo will see Prelude FLNG go into the history books as the world's fourth FLNG unit to start up.

Prelude was narrowly pipped into fourth place by the smallest LNG floater — Tango FLNG off Argentina — which shipped its first cargo late last week.

Shell has a 67.5% interest in Prelude FLNG, with Japan’s Inpex on 17.5%, South Korean LNG buyer Korea Gas Corp on 10% and Taiwan’s CPC Corp on 5%.

Valencia Knutsen takes on a first cargo from Prelude FLNG. Photo: Shell