As cmon knows I was right into the us shale oil sector when it was hot 5-6 years ago, eventually came to the realisation it is just another Ponzi scheme - high decay rates mean companies have to keep drilling to increase production, so have to raise equity or borrow to fuel the production curve. The question to ask is how many actually ever generate a real profit and dividend let alone even become cash flow positive...
All the while investors pay for the directors and management salaries...
Cheers, Sharks
PS and as for taking a punt it isn't speculative if you know it's not going to make money!