New natural gas field in Fars gas field in Iran with 7.5 trillion cubic feet of reserves was found.
With 5.7 trillion cubic feet seen was recoverable.
This distinction matters because not every molecule of gas found underground can necessarily be commercially extracted.
The recoverable portion depends majorly on the geology of the field, the technology available and the economics of developing it.
5.7 trillion cubic feet recoverable figure is more useful than the headline 7.5 trillion cubic feet figure when thinking about its eventual economic impact.
Newly discovered gas has also been described as "sweet gas", which generally contains relatively low levels of hydrogen sulphide.
As a result, its processing is made easier than for gas with higher levels of impurities.
Iran holds the world's second-largest proven natural gas reserves after Russia.