This is similar to the oil sands in Canada which is being developed on a monstrous scale. This has made Canada the #1 crude supplier to the U.S., all within the last 5 to 10 years. The u.s. oil shale supplies are well known.
There is a huge difference between tar sands and shale oil. The tar sands have been in development stages for 10-15 years and only recently has the production of oil from tar sands become cost effective. The time and dollars spent to refine the process have been huge.
Shale oil on the other hand represents a huge potential, as the oil is there. However, at this time the refining method or I should say the most cost effective extraction method is still to be developed.