Shale Gas Extraction
EPA Initiates Rulemaking to Set Discharge Standards for Wastewater from Shale Gas Extraction (PDF) (1 pp, 88K, About PDF)
Recent advances in horizontal drilling and hydraulic fracturing have made extraction of natural gas from shale formations more technologically and economically feasible.
Hydraulic fracturing is a method of extracting natural gas from highly impermeable rock formations by injecting large amounts of fracturing fluids at high pressures to create a network of fissures in the rock formations and provide the natural gas a pathway to travel to the well for extraction.
Geologic pressure within the shale formation forces these fracturing fluids back to the surface, where they are referred to as “produced water” or shale gas wastewater.
Based on a review of available data EPA is initiating a rulemaking to control wastewater produced by natural gas extraction from underground shale formations.
Shale Gas Wastewater
Shale gas wastewater contains high concentrations of total dissolved solids (salts). Shale gas wastewaters also contain various organic chemicals, inorganic chemicals, metals, and naturally occurring radioactive materials (NORM).
Currently, wastewaters associated with shale gas extraction are prohibited from being directly discharged to waterways and other waters of the U.S. In order to meet this prohibition, some of the shale gas wastewater is reused or re-injected, but a significant amount still requires disposal. Some operators reinject the wastewater into disposal wells. Other shale gas wastewater is transported to public and private treatment plants, which may not be equipped to treat this type of wastewater, resulting in the discharge of pollutants to rivers, lakes or streams where they can impact drinking water or aquatic life.
This rule would add a pretreatment standard to the existing regulation pertaining to oil and gas extraction.
Shale Gas Extraction and Natural Gas Production
The Energy Information Administration reported that in 2009 shale gas extraction represented about 15 percent of natural gas production, and they project that in the next 25 years that figure will triple.
Shale gas extraction is occurring in shale gas basins across the country. Maps from the Department of Energy depict the major shale gas basins.
EPA plans to propose a rulemaking for Shale Gas Extraction in 2014.