A couple of issues with your equation:1. Your $350 million is...

A couple of issues with your equation:
1. Your $350 million is the total value of ANA's share but it doesn't factor in the timeline of accessible gas. If the field is worked for ten years, it would be an average $35 million income pa. making your estimate 7-9 cps.
2. Using the current Market Capital, only covers the current shareholding. If the reservoir is commercial then the full range of share options would be taken up bringing the total to approx 600 million shares thereby reducing your figure by another 23%.
3. The total gross value of the reservoir will be A$18.4 billion, based on Andy Mathau's pricing in the link you referred to converted at the current exchange rate (A$1 = US$0.68 approx), which places your $1 billion estimate at 95% losses due to COP, royalties, porosity etc. Until actual levels are published a 75% loss could still be extreme. So that leaves you with a 5% return versus (say) 25% - which is 5 times more.
4. You can't just multiply two figures that are unrelated. Market caps are not "calculated" on just the EPS times the number of shares. You have to factor in for the gross $ value that allows that earnings level.
Typically in these circumstances, we would see a multiple of 20 or more.
If you put all these "standard" assumptions into an equation, the result is very promising and far above your estimate.

So let's hope there's something commercial and we can then work out the real calcs.
Cheers