for some idea of inground value of reserves,, and i mean just an idea.
http://www.businessweek.com/news/2010-09-01/petrobras-brazil-said-to-agree-on-oil-reserves-price.html
"Brazil will set an oil price ?in the middle? of a $5-to- $12 a barrel price range after studying two reserve studies by independent auditing firms"
Lets say its $8 IGV per BOE.
Hence every 1TcF its ~ 66c per share.