Shale oil and gas

How do you value these companies? China has the largest shale gas reserves but extracting in for commercial purpose is not going to happen till 2020 apparently. The USA has enough to last a long time. England is discovering its own. France disallows fraccing so it is not going to possible to extract its underground gas economically.

But some of the largest basins in the world are in Central Australia, covering vast areas in QLD, SA and NT. I have pumped some money into companies operating around this area. But so far, most have been losses because nothing substantial has been found yet. If the hype is true for most of these companies then I can probably retire earlier! Provided my wife does not spend big.

In the US, big companies like BHP and Shell have spent big buying up those 'small' shale gas companies. Will it be repeated in Central Australia?