[Amagi]

Not that many years ago shale oil was thought to be unobtainable, at least economically.
When it became obtainable there began to appear reasons why the oil shouldn't be retrieved, such as danger to the water table.
Yes, I endeavor not to underestimate the politics behind anything involving accessing the nation's energy resources.

[thackney]

Not that many years ago shale oil was thought to be unobtainable, at least economically.

You may be confusing oil shale with shale oil.

Horribly confusing terms, I know. Retorting shale to release Kerogen from the rock is far different than drilling into layers in/near the shale to get oil that was already cooked out.

[thackney]

Oil Shale vs. Shale Oil

http://www.coga.org/pdf_Basics/Basics_OilShale.pdf