santos' value

I'm interested into peoples thoughts on how much Santos is actually worth.

I've taken two approaches

1) NPV of cashflow's

Based on my workings from the GLNG presentations its future cashflow's are worth between $5B-$7B depending on how aggressive you are with oil prices.

Assuming that PNG LNG profitability is similar we can assume that it should be $2B-$2.5B

This leaves base busines. If we strip out the one-off items in the lastest CF statement it assumes FCF of $148m for 24.2MBOE or $300-318m on guidance of 49-52MBOE.

From this I get approx $4.5-5.0B with a fall in out years as reserves decline.

This gives a total of $11.5B-$14.5B vs current market cap of $11.4B. $14.5B gives a share price of $16.42

2) PE multiple

Using same assumptions as above GNLG EPS are approximately 53c and PNG 20c (74c and 28c with aggressive oil price).
Current Consensus estimate for base is 40c in 2011 and 57c in 2012.

If all this holds true and GNLG + PNG are pulled off on time and on budget STO EPS = $1.13-$1.26

So now its share price comes down to what mutliple it trades at $12.60 at 10x, $15.12 at 12x, $17.64 at 14x.

My analysis doesn't take into account other projects (eg Bonaparte or exploration fields).

My thoughts are a lot of the upside is already baked in and a re-rating is not going to be massive.

I hold but am questioning whether a reward of 15%-25% upside potential worth the downside risk.

Thoughts?