What is Hydraulic Fracturing? Back to Blog
According to Range Resources’s corporate website, hydraulic fracturing is a method in which water and sand are pumped down the wellbore at high pressure in order to create cracks and fissures in the rock to allow connectivity to the wellbore with the sand keeping the newly created passageways open. This allows the natural gas that was otherwise trapped in the rock to flow with its natural pressure differential between the surface and reservoir deep under ground. This process was first used commercially in the U.S. in 1949. Over the past 60 years, more than one million wells have been hydraulically fractured with no incidents of any impact to our drinking water. Today, almost 90% of wells drilled in the United States are stimulated with hydraulic fracturing in order to allow or increase production. The process has been studied by multiple regulatory agencies, including the Environmental Protection Agency (“EPA”), and declared safe. The EPA’s last full study report was conducted in 2004 and can be found on the EPA website. (Links to those studies and other facts are included in this website tab under “Hydraulic Fracturing Studies”) Furthermore, the Ground Water Protection Council (“GWPC”), which is composed of professional regulators from over 30 states working on ground water issues, issued a report in April of 2009 stating that the potential for hydraulic fracturing in deep shale gas wells to impact groundwater is extremely remote, as low as one in 200 million. This safe, time-tested technology, coupled with horizontal drilling, has allowed access to an enormous amount of new natural gas reserves in America. Safety is ensured by nature and by design. Strict regulations require producers to fully isolate the wellbore to well below all fresh water aquifers with multiple layers of steel casing and cement. In addition, petroleum engineers carefully design and monitor the fracture process. Finally, nature adds insurance. Groundwater aquifers are found generally at 80 to 500 feet below the earth’s surface depending on the location, while the fracture process takes place more than a mile below the surface in the shale wells thousands of feet below any fresh water. Layers and layers of impermeable rock form natural seals to prevent natural gas from migrating to the fresh water. Gravity also works with the process since water will tend to move down in the formation rather than rise.
Every oil and gas well is designed and constructed to provide protective barriers that protect our drinking water. The fact that state agencies, the primary regulators of oil and gas exploration and production, have testified before Congress that there has not been a single confirmed instance of any impact to our drinking water resulting from hydraulic fracturing operations seems to have been ignored amid a great deal of misinformation.
Every aspect of well permitting and construction is highly regulated. Range goes to great lengths to ensure our well integrity by using top-rated contractors and materials. In Pennsylvania, for instance, Range, samples all water sources (e.g., including water wells) within 1,000 feet of our drilling locations before our drilling. We use certified third party environmental laboratories to collect and analyze these samples. We also install steel casing completely across the aquifer, often called surface casing. Given the additional casing that we have to run into the well, the aquifer zone will be protected by a total of three or more steel casing strings depending on the specific location and depth of the well. In addition depending on the location, when we drill through the shallow aquifer zone, we employ either fresh water based mud or drill with air.
Typically, it takes 3 to 4 million gallons of water to fracture stimulate a shale well, which is equivalent to water usage at a typical golf course for nine days. Moreover, the fracture process is generally a one-time occurrence, after which the gas well is likely to continue producing for 50 years or longer. Relative to other forms of energy, gas production is not highly water intensive. Ten times as much water is required to produce the equivalent amount of energy from coal and ethanol production can require as much as a thousand times more water to yield the same amount of energy from natural gas. Water for drilling and hydraulic fracturing can come from surface water bodies such as rivers and lakes, but can also come from ground water, private water sources, municipal water and re-used produced water. Whatever the source, water used in the drilling and fracturing process is highly regulated and permitted to ensure that withdrawal does not interfere with available supply for other users nor disturb the aquatic eco-systems present. Many states require an analysis to ensure that any proposed water withdrawals will not harm the watershed by adversely affecting stream flow, aquatic life, recreational resources or sensitive environments.