[ckilmer]

In short, OPEC will find out in the next 25 years what happens when Russia, USA and Canada become the world’s biggest oil and natural gas producers. The free ride the Sunni Arabs got from all the all production in the southern Persian Gulf could soon be over.

.....
My betting is that Saudi oil is the cheapest to extract. Any fall in prices will constrain production of American frackers first.

However, the government there gets most of their revenue from oil. So the saudi government would be sorely crimped by falling oil prices. Same goes for the Russians. Both would have have less money available for adventures.

[Praxeologue]

My betting is that Saudi oil is the cheapest to extract. Any fall in prices will constrain production of American frackers first.

Cost varies.

Oil Basin Breakeven Estimates as of late-2013 ($/bbl): Eagle Ford $65, Bakken Core $75, Permian $80, Niobrara $80, Bakken Fringe $85, Utica $85, Mississippian $85, Cana Woodford $90, Ardmore Woodford$95. (all unconventional) [source], plus, for all types:

[source]