The largest factor in whether oil gets extracted from shale is the Energy Returned On Energy Invested (EROEI). Some oil formations simply take a gallon of fuel to create a gallon of fuel, a 1:1 EROEI. That makes it useless until there is a major breakthrough in efficiency for oil extraction. Canada's oil sands are very low at a 3:1 EROEI. The Middle East EROEI is very high at over 40:1.
Gosh, really?
According to self-asserted forum energy expert RGR, that EROEI stuff is a nonsensical measurement that no one uses, and is no factor in comparing different forms of energy.
It's funny watching denialists squawk until they're blue in the face, using long-debunked talking points over and over again, that there's "plenty" of energy. But, ultimately, you're all eventually forced to concede many of the main contentions brought to you. EROEI and proven reserve vs. estimated reserves being just a few key aspects.
So yes, that's right.... EROEI is THE fundamental aspect of assessing net energy. Anything less than 5:1 is NOT -- i repeat NOT -- maintaining the kind of growth the world economy requires. When people lie to themselves and insist that tar sands and shale oil formations will "save the day," they don't really have any idea what they're talking about. The technology has been around for decades, and they can not figure out a way to bring it to market efficiently.
Resources are not reserves. Satisfyingly, it appears that is something RGR and I can come to agreement about.