This is a simplistic illustration of the basics of hydraulic fracturing (aka fracking), which I have annotated in red. It was commissioned by the EPA for public consumption and is primarily used in presentations about what the agency is doing in its “study” of fracking. As such, it’s a truly nasty piece of work because it’s so exclusionary in its detail. And as if that wasn’t bad enough, with or without attribution, it has also become a handy tool in the fraudulent fracking safety presentations of many special interest groups, industry reps, and producers.
Part of what makes it pernicious is that the monochromatic rendering of subsurface strata gives the impression that the many zones are homogeneous, which couldn’t be further from the truth. There is a great deal of downhole variety, which may include water-bearing strata (aquifers) and pockets of gas such as Hydrogen Sulfide or Methane. Also problematic is the impression that the strata are at more or less uniform depths, which is completely at odds with the fact that God doesn’t do straight lines or neat boundaries.
Most troubling, however, is the inset, which gives the impression that fracking opens up sufficiently large, neat, and harmless fissures in the production zone which are then kept open by the introduction of sand. And that’s where the Devil lives.
What’s at issue is the fact that any given production zone, which in this illustration is the Marcellus Shale, won’t give up its bounty because it’s impermeable. And what has made it impermeable is the massive weight of the 7,000+ feet of overburden which has accumulated over the more or less 387 million years since the first layers of sediment (silt) which became the Marcellus Shale were deposited.
Fracking can and does create some degree of permeability in the shale, but the fracturing also weakens the shale and eventually the weight of the overburden will overcome the weakness and lead to such things as earthquakes and sinkholes in places where they were otherwise geologically impossible.
It doesn’t take a genius to understand the vulnerability – It would be obvious to any Geology 101 student or to anyone who’s spent as little as six months in the oil patch. And the EPA professional staff damn well know it.
So, why isn’t the agency very publicly denouncing the practice?