Brez's spreadsheet is too low...
The going rate for proven undeveloped reserves is $12, and as I said earlier the full carries up that number significantly, I'm guessing as high as $20.
Change the spreadsheet percentage from 9.5% to 20% and it values reserves (at the $80/b price point) at $12.
Then punch 4000, 3000, and 3000 for blocks 2, 3 & 4 proven...
Whoa nellie!