Whereas drilling intensity won't prevent the United States from becoming the largest oil producer globally in just few years, it will likely prove a daunting obstacle for the rest of the world--for several reasons.

First, the United States holds more than 60 percent of the world's drilling rigs, and 95 percent of these are capable of performing horizontal drilling--which, together with hydraulic fracturing (fracking), is crucial to unlock shale production. No other country or area in the world has even a fraction of such "drilling power," which takes several years to build up. For example, all across Europe (excluding Russia) there are no more than 130 drilling rigs (as against 180 in North Dakota alone), and only one-third of them are capable of doing horizontal drilling.

Moreover, no other country has ever experienced even a fraction of the drilling intensity that has characterized the U.S. oil and gas history.

Consider: in 2012 the United States completed 45,468 oil and gas wells (and brought 28,354 of them on line). Excluding Canada, the rest of the world completed only 3,921 wells, and brought only a fraction of them on line. To my knowledge, Saudi Arabia brings on line no more than two hundred wells per year.

Other factors will contribute to prevent the development of shale resources in the rest of the world.

One is the absence of private mineral rights in most countries. In the United States, landowners also own the resources under the ground--and have a very strong incentive to lease those rights; in the rest of the world, such resources usually belong to the state, so that landowners usually get nothing from drilling on their lands but the damage brought about by such activity.

Also absent outside North America are independent oil companies with a guerrilla-like mindset, a crucial aspect of the U.S. boom. Until now, the development of shale resources has not proved to be Big Oil's strength--since shale oil requires companies capable of operating on a micro-scale, pursuing a number of micro-objectives and leveraging short-term opportunities. Only the United States (and partly Canada) possesses a plethora of such aggressive companies. It is no accident that they have been, and still are, the protagonists of the shale revolution.

Finally, we even don't know with any reasonable approximation either the real size of the shale formations in the world, or the costs to develop them. The problem is that the geology of the United States is by far the best known, explored, and assessed, whereas for most countries shale deposits are a matter of pure speculation. [...]

True, the amount of crude oil imported each day by the United States has plummeted steadily from its peak in 2007 (when it reached more than 10 million barrels), and it will probably be less than 50 percent of consumption by the end of 2013. However, even in the most favorable scenario I outlined above, 25 percent of U.S. crude oil requirements will have to be imported in the future.

This implies that if the United States wants to target the highest degree of oil security, it should rely not only on an increase of its domestic crude-oil production, but also on energy-efficiency measures that could curtail crude-oil consumption.