The article describes the difficulty of extracting the oil while still turning a profit, with passing mention of some of the environmental and social concerns associated with the extraction processes that might be involved.
This is not a blog post about hydraulic fracturing, per se, but a brief comment on the use of language: the headline reveals a way of framing the meaning of shale oil that cuts off any debate about the advisability of extracting the oil before it can get started.
It comes down to a matter of metaphor.
To trap something is to confine or limit it when it would otherwise move freely.
To say the oil is trapped is to suggest that oil in its natural state is free. The oil would be free, could be free, and should be free but for the damned, cruel, oppressive shale formation holding it back!
What's proposed then is not "fracking" - such an unpleasant word, "fracking" - it's Oil Liberation!