The idea for underground fracturing goes back to the Civil War, when an officer was inspired by the results of firing an artillery round into a narrow canal. That officer filed a patent in 1865 for a process to improve the production of oil wells by dropping an explosive charge down the well hole. The method increased production from some wells by more than tenfold.
Modern hydraulic fracturing, or fracking, employs a completely different method. It was first used in a southwest Kansas well in 1947. It’s evolved considerably over time.
So why does it seem like such a recent phenomenon? In the 1990s, drillers began combining fracking with horizontal drilling. Then in 2010, the price of oil rose to the point that it became economical to greatly expand the process. That’s when it began to pay to make multiple horizontal wells from a single, main-vertical well shaft, and fracture the oil-bearing rock along those horizontal shafts. The process resulted in immense improvement in the amounts of oil and gas recovered from these wells. And the United States nearly overnight became energy independent.
The fracking process is straightforward. The producer sinks a vertical shaft to the oil-bearing formation. Sophisticated and highly accurate equipment allows the drilling of horizontal shafts – usually multiple shafts from a single vertical shaft – that follow the oil-bearing layer. Then a mixture of water and sand, with the addition of a small amount of various chemicals to improve the process, is injected into the horizontal shaft under extremely high pressure. The pressure creates many small fractures – most are 1 millimeter wide or smaller – in the surrounding rock. The sand gets in the cracks and serves to keep them open.
The fractures greatly increase the amount of oil and gas that can seep through the rock and into the pipeline for extraction.
Chemicals added to the fracking water constitute less than half of 1 percent of the total volume. And none of them are toxic. One of the main additives used is guar, an additive typically found in ice cream. Others prevent bacteria in the well or break water surface tension so it can be more easily injected and recovered.
However, the water can’t be used for human consumption, so it must be disposed of. About a third of the water stays in the well. An ever-increasing volume of the returned water is moved to other drill sites and reused. And some of it is reinjected into deep disposal wells, far below any potable groundwater sources.
Together, horizontal drilling and fracking require far fewer surface drilling sites – and their attendant environmental impacts – while increasing the yield exponentially. That keeps oil money and jobs in the United States, while reducing the cost of energy.
In the past decade, North Dakota grew from the nation’s ninth-largest oil producer to the second-largest, thanks almost entirely to the success of fracking in that state’s Bakken and Three Forks formations.
As a state that traditionally relies on agriculture to power its economy, North Dakota understandably keeps a close eye on its most precious resource: water.
The agency charged with that oversight – the North Dakota Water Commission – reports that hydraulic fracturing or fracking poses no risk to contaminate the state’s groundwater resources.
That’s because oil and gas well fracking takes place about 10,000 feet – nearly two miles – below the surface, while fresh groundwater comes from 2,000 feet or less deep. There’s about a mile and a half of rock layers between the oil-bearing region that is being fractured and the freshwater aquifers near the surface.
The same is true in Colorado, where oil and gas developers have been fracking wells for more than four decades. That state’s four major aquifers run for the most part within a few hundred feet of the surface, although some water wells may draw from as deep as a half a mile (2,600 feet). Meanwhile, fracking occurs 6,000 feet or more below the surface.
In a recent white paper on water and fracking, the North Dakota Water Commission says its only concern is that development companies are forced to use groundwater for drilling, rather than tapping into the plentiful supplies flowing through the state in the Missouri River.
Oil or gas wells in North Dakota that use hydraulic fracturing – virtually all do – require a total of about eleven acre-feet for the drilling and fracking process, which occurs in just a few days.
There’s no danger that drilling and fracking activity would deplete groundwater resources, however, the commission says, because it sets limits on all groundwater withdrawals and keeps close tabs on the amounts used. If a water-using entity reaches its annual allotment before the end of the year, it is required to shut down operations until the next allotment period begins.
On the other hand, the state commission laments the U.S. Army Corps of Engineers’ restrictions on water withdrawals from Lake Sakakawea, an impoundment on the Missouri River.
In 2013, when drilling was at a peak, fracking operations used a little less than 20,000 acre-feet of water in total, or about 5 percent of all the water consumed in the state that year. That’s about how much water flows down the Missouri every 12 hours, on average. In fact, in three days, enough water flows through the Missouri to service every well that’s ever been fracked in the state.