Energy security in the United States may be an achievable goal for the first time in nearly 40 years. Credit largely goes to the shale boom; its epicenters are in places like Texas, Pennsylvania and North Dakota, not Washington, D.C. The economic benefits — jobs, royalty and tax revenues and lower natural gas prices — reverberate nationwide. Forget Occupy Wall Street: This is a real revolution.
Shale is the most common sedimentary rock, and certainly the one with the least glamorous pedigree. Shale started as mud, deposited in a lagoon, a swamp or the deep ocean.
With burial, and over geologic time, the suspended organic matter in shale cooks into a hydrocarbon gumbo. But shale lacks permeability, the property that allows fluid flow within a conventional sandstone or limestone reservoir. Geology 101, circa 1975, taught us to ignore shale as an exploration target.
Nobody knew then that within 30 years drillers would find the key for turning common shale, the Ugly Betty of sedimentary rocks, into a supermodel. Innovative drilling methods can steer a well path horizontally through 10,000 feet of hydrocarbon-bearing rock, a 100-fold increase compared to a vertical well.
A hydraulic fracturing treatment (“fracking”) creates permeability, enabling flow at commercial rates.
In a decade, shale gas production has grown from insignificance to one-third of our nation’s natural gas supply. The nation’s two most productive natural gas fields produce from shale.
Taken as a separate source of supply, shale gas now provides eight times more energy than wind and solar power combined. In fact, the shale gas share of the nation’s total energy picture rivals all renewable energy (wind, solar, hydro, geothermal and ethanol) and nuclear energy in size.
Success in gas shale is paying dividends in oil, too. Some shale plays produce condensate, a high-quality crude oil equivalent, as a gas byproduct. The Bakken Shale was the first play with oil as the primary objective; within a few years the Bakken may account for 10 percent of domestic oil production. Shale formations in several other basins are prospective for oil.
Conventional permeable reservoirs must be geologically situated so that fluids can migrate in, but not leak out. Consequently, they tend to be limited in size. The largest domestic oil field, Prudhoe Bay, would cover just a quarter of the state of Rhode Island.
Oddly, the commonness of shale is its major advantage. Shale formations often cover an entire sedimentary basin. The Bakken, for example, covers western North Dakota and eastern Montana, and spills into Canada.
Since the oil or gas is generated within the shale, the quality of an accumulation depends only on the rock itself. Dry holes in shale are virtually unknown. When conducted on a large scale, shale development becomes more like a manufacturing process than a geologic crapshoot.
Peak Oil guru M. King Hubbert did not foresee horizontal wells, so his famous prognostication of the near-term demise of fossil fuels understandably did not take shale drilling into account.
Hubbert made passing reference to the so-called “oil shale” of the western states, but he did not consider it to be the ultimate answer to our energy needs. (This oil shale contains a waxy immature form of oil, quite a different technical challenge.)
Ironically, Hubbert predicted in the same paper (“Nuclear Energy and the Fossil Fuels”, 1956) that as the hydrocarbon age wanes, the nation would tap its virtually inexhaustible supply of fissionable material. And where will we find all that uranium and thorium? Why, in shales, naturally.
Steve Maley is operations manager of a small Gulf Coast oil and gas producer in Lafayette, La., and a contributing editor at RedState.com.
