It took some time for hydraulic fracturing—or “fracking”—to become as widespread as it is today. Although American entrepreneurs have known for more than a century how to crack open rocks deep below the earth’s surface to access trapped fossil fuel deposits, fracking gained a serious foothold in the nation’s energy market only in the past two decades. During this time, a fracking boom has helped the United States become the global leader in natural gas and crude oil production.
What Is Fracking?
Modern high-volume hydraulic fracturing is a technique used to enable the extraction of natural gas or oil from shale and other forms of “tight” rock (in other words, impermeable rock formations that lock in oil and gas and make fossil fuel production difficult). Large quantities of water, chemicals, and sand are blasted into these formations at pressures high enough to crack the rock, allowing the once-trapped gas and oil to flow to the surface.
History of Fracking
The idea for fracking—or “shooting the well,” as the practice was once referred to—dates back to 1862 and has been credited to Colonel Edward A. L. Roberts. In the midst of fighting during the Civil War’s Battle of Fredericksburg, Roberts noted the impact that artillery had on narrow, water-filled channels. A few years later, he applied his battlefield observations to the design of an “exploding torpedo” that could be lowered into an oil well and detonated, shattering surrounding rock. When water was then pumped into the well, oil flows increased—in some cases by as much as 1,200 percent—and fracking was established as a way to increase a well’s productive potential.
In the 1940s, explosives were replaced with high-pressure blasts of liquids, and so “hydraulic” fracking became the standard in the oil and gas industry. It wasn’t until the beginning of the 21st century, however, that two key changes helped spark fracking’s current boom. One was the use of a certain type of fracturing fluid: slickwater, a mix of water, sand, and chemicals to make the fluid less viscous. The other innovation was the pairing of fracking with horizontal drilling, a technique that increases the productive potential of each well because it can reach more of the rock formation that contains the oil and gas. These advances, combined with an influx of investment amid high global fossil fuel prices, sent fracking into overdrive. Indeed, of the approximately one million U.S. wells that were fractured between 1940 and 2014, about one-third of those were fractured after 2000.
How Does Fracking Work?
It involves blasting fluid deep below the earth’s surface to crack sedimentary rock formations—this includes shale, sandstone, limestone, and carbonite—to unlock natural gas and crude oil reserves.
The process begins with the drilling of a long vertical or angled well that can extend a mile or more into the earth. As the well nears the rock formation where the natural gas or oil lies, drilling then gradually turns horizontal and extends as far as thousands of feet. Steel pipes called casings are inserted into the well, and the space between the rock and the casing is fully or partially filled with cement. Small holes are made in the casing with a perforating gun, or the well is constructed with pre-perforated pipe. Fracking fluid is then pumped in at a pressure high enough to create new fractures or open existing ones in the surrounding rock. This allows the oil or gas to flow to the surface for gathering, processing, and transportation, along with contaminated wastewater that is stored in pits and tanks or disposed of in underground wells.
Fracking Equipment
Hydraulic fracturing requires an extensive amount of equipment, such as high-pressure, high-volume fracking pumps; blenders for fracking fluids; and storage tanks for water, sand, chemicals, and wastewater. This infrastructure, plus more, typically arrives at drill sites via heavy trucks.
Source: NRDC (Natural Resources Defense Council), Credit: Fracking 101- by
