Many questions arise when people discuss hydraulic fracturing in their communities. The following are answers to frequently-asked questions related to this technology. If you have a question that is not addressed here, please email firstname.lastname@example.org.
- Can the process of hydraulic fracturing contaminate my drinking water?Drinking-water wells reach a depth of 200 to 500 feet. Meanwhile, the actual fracturing takes place at 5,000 to 9,000 feet below the surface, far beyond the fresh-water zone. In addition to the distance that separates the fracturing zone from the fresh-water zone, the construction of the well and the casings used are critical components in ensuring safe drinking water. The multiple layers of steel and cement casing keep the well isolated from the water and help prevent natural gas from leaking outside the pipe. Tests are conducted over the life of the well to verify long-term well integrity and groundwater protection.
- How much water is used in hydraulic fracturing? Each site can require 3 to 5 million gallons of water to drill and complete. According to the US Department of Energy and the Groundwater Protection Council, this accounts for fewer than 1% of total water demand in most regions. Hydraulic fracturing is one of the most water-efficient ways to produce energy, requiring only a fraction of the amount of water to produce the same amount of power as nuclear, coal, ethanol from corn, or biodiesel from soy energy production processes.
- What happens to the water after it is used?Water used in the hydraulic fracturing process is usually managed and disposed of in one of three ways. It can be injected in permitted disposal wells in accordance with US Underground Injection Control regulations; delivered to water treatment facilities, depending on permitting; or recycled and reused. Typically, 10% to 30% of the water used returns to the surface through the pipe and is referred to as “flowback.”
- What chemicals are added to the fracturing fluids?Water and sand comprise approximately 98% to 99.2% of the fracturing mixture. The remaining 0.8% to 2% is composed of materials found in common consumer products, such as clay stabilizer, acid, and friction reducer. While each well will vary in terms of quantity and types of chemicals used, each site must use these chemicals to protect the well from corrosion.
- Is the air quality affected?Natural gas is considered a clean-burning fuel because of its low emissions of carbon dioxide, sulfur oxides, and nitrogen oxides. Air emissions from fracturing are carefully monitored, managed, and reported. Any emissions from oil and gas activity must remain within prescribed state and federal limits to ensure the health and safety of local communities. The industry has made considerable strides in reducing emissions through voluntary measures, and is working with the US Environmental Protection Agency to define New Source Performance Standards (NSPS) that will give rise to additional reductions.
- Does fracturing cause earthquakes?There is no evidence that fracturing causes earthquakes. In rare cases, low-strength seismic tremors, a million times weaker than the smallest, damage-producing quake, may be generated. However, fracturing does not penetrate deep enough to reach active tectonic plate boundaries (the giant pieces that form the top layer of the Earth’s crust).
The Society of Petroleum Engineers is only one of the many organizations educating the public about hydraulic fracturing. The following links offer additional information related to hydraulic fracturing:
- Range Resources Hydraulic Fracturing Fact Sheet
- Shale Energy: 10 Points Everyone Should Know
- The Tantalizing Promise of Oil Shale
- Depending on Guar for Shale Oil and Gas Development
- Hydraulic Fracturing 101
- Making Sense of the ‘Overnight’ Shale Gas Revolution
- Water Recycling Grows in the Marcellus Shale
- Brine Management: Produced Water and Frac Flowback Brine
- The Facts About Hydraulic Fracturing and Seismic Activity
- Animation of Hydraulic Fracturing
Courtesy of Marathon Oil Corporation
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