Environmental Impacts of Horizontal Natural Gas Drilling

Horizontal drilling and the accompanying process known as hydraulic fracturing are methods by which energy producers access and extract natural gas stored deep underground in shale deposits. Although horizontal drilling provides maximum contact with gas-containing rock formations and allows the drilling of multiple wells from the same location, it is the fracturing process that raises deep concerns over environmental impacts.

Drilling Methodology

• Deep drilling rigs act as a brace to support drills, which bore vertical wells extending up to a mile into the Earth. Upon reaching the shale deposit, drill operators, through the use of special instruments and techniques, steer the drill to the side until it begins to bore horizontally. Once the boring instrument is in the proper position, it is capable of traversing thousands of feet horizontally through the shale.

Hydraulic Fracturing

• Hydraulic fracturing is the process that moves natural gas from shale formations to a production well. Fluids, consisting of water and chemical additives, are pumped into a shale formation at pressures exceeding rock strength, thereby opening or enlarging fractures, which may extend several hundred feet from a well. Various propping agents are then pumped into the fractures to keep them from closing. The chemical agents used in the fracturing process hold the potential for causing serious adverse environmental impacts.

Chemical Danger

• The Endocrine Disruption Exchange reports that toxic chemicals are used during all stages of horizontal drilling operations. The fracturing process requires one million or more gallons of water mixed with dangerous substances during each operation. The organization points out that between 30 and 70 percent of the fracturing fluid resurfaces above ground. Use of these chemicals for natural gas production is exempted from federal regulation by the Energy Policy Act of 2005. Additionally, volatile chemicals, such as benzene, toluene and xylene mix in the atmosphere to create layers of ozone.

Water

• In February, 2011, the Arkansas Public Policy Panel issued a report titled "Arkansas in the Balance: Managing the Risks of Shale Gas Development in the Natural State." The document warns that the fracturing process requires the removal of millions of gallons of freshwater from local aquatic bodies, thereby posing a direct threat to wildlife habitat. Additionally, the cumulative effect of toxic chemicals introduced into the environment, either deliberately or by accident, endangers the integrity of both aquifers and water above ground.

Other Effects

• Horizontal drilling operations often require the construction of roads and pipelines, which may result in the clearing of thousands of acres of land. Toxic chemicals found in holding ponds, disposed of in injection wells or spread over land illegally pose a direct threat to humans, domestic animals and wildlife. According to the Arkansas Public Policy Panel, there have been numerous violations of that state's disposal laws by the gas industry.