Hydraulic fracturing or “fracking” is a technique employing a highly pressurized mixture of water, sand and chemicals to extract oil and natural gas from shale deep beneath the Earth’s surface. Although the basic technology has been known for decades, fracking has boomed since 1998. Fracking currently produces more than half of the oil and two-thirds of the natural gas for the United States.
From a vertical well that is drilled thousands of feet deep, a horizontal well is drilled into shale in which deposits of oil and natural gas are trapped. The fracking liquid is pumped down the well with sufficient pressure to fracture the shale and release the entrapped oil and gas. Wastewater that is pumped back to the surface is disposed by injecting it under high pressure into separate, deep wells.
Dr. Clif CleavelandIn addition to the chemicals used in extracting oil and gas, a variety of heavy metals, organic compounds and naturally occurring radioactive substances are released when shale is fractured. These contribute to the toxicity of the wastewater.
More than 300,000 wells in 21 states were in operation in 2016. A typical well and related structures occupy three to five acres. Texas, Pennsylvania, Kansas, Montana, North Dakota and Ohio lead the nation in numbers of wells. Although large shale deposits are located beneath Southeast Tennessee and Northwest Georgia, there has been little fracking activity in the region. Fracking is banned in New York, Maryland and Vermont.
Here are some points to consider about fracking.