"The Australian dollar has depreciated nearly 30% since April 2013, which may prevent cost overruns for projects decided after 2012, such as Inpex's Ichthys," Bloomberg Intelligence LNG analyst Lu Wang said.

"The Aussie appreciation from 2010 to 2012 contributed to cost overruns at the Curtis, Asia-Pacific, Gorgon and Gladstone projects, which all revised up capital expenditure in 2012."

April 2013 has additional significance for being the month that Woodside shelved the onshore, James Price Point version of its Browse LNG project with high wage costs and the soaring Australian dollar taking some of the blame.

Shell's $US11.7 billion ($A15.1 billion) Prelude FLNG project and Chevron's $29 billion Wheatstone LNG project, which both reached final investment decisions in 2011, have also faced no cost overruns so far as they advance towards their first LNG milestones (Wheatstone 2016, Prelude 2017).

This compares with cost overruns in the scales of 46% for the Gorgon LNG project so far, 36% for the Queensland Curtis LNG project, 28% for Australia Pacific LNG and 16% for Gladstone LNG.