This follows two previous dry holes in the Pluto exploration area at Ixion-1, drilled earlier this year, and Belicoso-1, drilled late last year.

On May 1, Woodside chief executive Don Voelte told the company's annual general meeting that the company would have to approve construction of the second train by late next year to keep its timetable intact.

Woodside needs to find a new gas supply for the second train soon or risk being unable to roll over the construction workforce from Pluto's first train to the project's second train.

In the event of not finding enough of its own gas, Woodside's back-up plan had been to develop the train wholly or partly as a gatherer of other companies' gas.

But this is also looking like an increasingly tenuous hope.

The major gas discoveries near Pluto are held by US companies Chevron and Apache Energy. However, Chevron aims to develop the nearby Wheatstone and Iago fields for a liquefied natural gas project of its own, and Apache is planning to process gas from fields on the Julimar trend at its Devil Creek gas plant for sale into the lucrative Western Australian domestic market.

Woodside has two more exploration wells to drill in the greater Pluto area before the end of the year. A lot is hanging on their results.