I think the reasons for not doing a share buyback is that the...

I think the reasons for not doing a share buyback is that the company believes it can unlock better value with its money in developing its current oil/gas holdings. If it got to the stage where they had no great prospects then a share buyback might be alright but there's so much development and exploration to be done with their current tenements it's just not feasible.

Sure, their P/B ratio is only about 0.6 at the moment, so they're definately trading well below NTA, but if you can get a 300% return on developing your prospects and 200% buying back your own shares, you'll get better value out of developing your prospects, and who knows, you might find an oil field elephant - like in Tanzania - the oil is seeping out of the lake for gods sake, we just have to find the kitchen and milk it for all it's worth :)