I don’t know....I got the text I posted in an email, went to the link, saw it had most of the same text and pasted it.
http://www.eia.doe.gov/pub/oil_gas/natural_gas/feature_articles/2006/ngshock/ngshock.pdf
Maybe the difference is between what is there and what is technically recoverable....
There were a lot of wildly inflated overestimates floating around before the USGS report came out.
It’s a nice field but it’s not remotely comparable to Saudi, and it’s fairly difficult to recover.