I can see a few probs with your maths and figures in general...

I can see a few probs with your maths and figures in general Blackjack.
Firstly, 65% of 17tcf is about 11tcf not the 17tcf you used while BPT have 90% of PEL218 and a 20% interest [increasing soon] in the other 10% [ADE].
Secondly, PEL218 in the SA Cooper Basin has only had two shale gas wells drilled so far and the whole acreage is strongly predicted by bpt to be thick shale at that Nappamerri Trough depth and it covers a massive 1600sq km, if you read the whole announcement and not just the 2tcf resource for the 100sq.km so far appraised by the two wells.
So 1600/100 = 16 and 16 times 2tcf = 32 tcf X 92% = approx 30tcf
Thirdly, across the border in the adjacent QLD permit ATP855, the same vast Nappamerri trough shale continues into qld where BPT has 40% and ADE 20% giving BPT a controlling interest in this, as yet undrilled for shale gas, tenement.
Fourthly BPT is also a partner in the South Aust. Cooper Basin JV as well as many BPT operated permits in the Cooper/Eromanga basin and so produces oil & gas there as well as from overseas [egypt] and offshore Victoria.
The share prices of esg v bpt is irrelevant in comparing market value or worth but Market Cap is;
bpt M'Cap is around $1,100 Million v ESG $754 Million even despite bpt's sp is not being propped up by a TO offer at present like the ESG sp is.
This Market Capitalisation or company value also reflects the company's production revenue and profit results along with forecasted future revenues & profits;
dividends also play a part with bpt paying 2 or even 3 divs a year for several years now [yes a special div. too one year]. Does esg pay divs?

I have no beef with esg or even with CSG [coal seam gas] for that matter and I see esg as a short term buy on the strength of the santos bid as santos is a serious gas player that I have great respect and regard for but do not hold.
I do however bristle at the suggestion that my long-held Beach is worth less than ESG on the basis of a comparison of a BPT INITIAL shale gas resource from Holdfast-1 and Encounter-1 test results with ESG csg resources;
and by a comparison of their share prices? as on the BPT thread.