shrewd crude report valuation, page-16

A major flaw in your assumption is that you expect flow rates to stay consistent over the entire 20 year period.
Sorry but that is just ridiculous - ever heard of the production curve or natural rate of decline?

Also be wary in using an $8/MCF rate for the entire 20 years. There is alot of new supply coming into the domgas market - Devil Creek has started (Apache), Macedon due in 2013 (BHP), Wheatstone 2016 (Chevron). These are large scale projects all with domgas plants which will significantly increase supply in the future. Add to that supply if all the WA Shale Gas companies make it to market and i think you will find $8/MCF is very optimistic

I wouldn't go basing a price assumption on a single quote from a Minister.