I am going to assume (big assumption but I think warranted in light of the wells already drilled and tested) that Elk/Antelope is at least 9 tcfe and therefore TOTal will pay the "max" price of $3.6 Billion.
Now, the current market cap of IOC (at today's closing of $88.63) is about $4.34 Billion.
$3.6 Billion is 83% of $4.34 Billion.
So, TOTal is paying out (over time) to InterOil 83% of their current market cap. Pretend that InterOil immediately took the cash and retired shares (just a fiction to show how bullish the price is...) - in theory they could retire 83% of their shares. That would leave the remaining 17% shares owning 100% of: 30% of the PRL15 resource, 30% of the future earnings of the LNG plant that TOTal will build, a majority interest in all the other leases/prospects they have (including Triceratops which is a gas discovery in its own right), 100% of a refinery, 100% of a retail and commercial distribution system for gas/diesel/naptha/etc., and the list goes on (there are other things that I've probably missed).
Just a different look at the deal...

