Water: Use, Preservation and Protection

Several of the main environmental concerns associated with shale gas focus on water: how much is used and the potential for contamination.

Over the years, the natural gas industry has developed many best practices to protect surface and groundwater. The amount of water required for shale gas extraction is one of the most important issues the industry is actively seeking to address. The industry is working with regulators and environmental organizations to explore innovative methods to reduce water use and waste water.

Water quantity – for use and disposal

Shale is an extremely dense rock. It takes a lot of pressure to fracture the shale and release the trapped gas – requiring more water than used in more porous rock.

The average shale well uses 3 to 6 million gallons of water for hydraulic fracking. While the amount of water used in this type of drilling is relatively small compared to uses like agriculture, it is a new and growing demand on a critical and limited resource.

A second problem is what to do with flowback and produced water. Flowback is the fracking fluid that comes back out of the well, usually during the first few weeks after fracking is completed.

Produced water is water that always comes from the earth along with oil and gas production. These fluids contain salt and some naturally occurring heavy metals and may contain small amounts of chemical additives from the fracking process. These waste products must be properly managed.

Initially, some producers sent this wastewater to municipal treatment facilities, which sometimes were overwhelmed by the volume. But in recent years, the industry has adapted new techniques to manage water. For example, in the first half of 2012, drillers in the Marcellus Shale areas of Pennsylvania were reusing 76 percent(3) of their water. Range Industries was recycling 96 percent of its produced water by 2010.(4)

This means less water is used, and there is less water to dispose of. Increasingly, gas developers create water management plans, working with local and state governments to ensure that use of water for fracking doesn’t conflict with other regional needs. Furthermore, the industry is working hard to develop alternatives to fresh water for fracking.

For example, a successful Canadian operation uses an underground aquifer containing saline water that is not fit for most common fresh water uses. Coupled with a specially designed treatment facility, this water source provides about 95 percent of the water needs for drilling operations in the area. Shell has built a wastewater treatment plant for the City of Dawson Creek in Canada. The company is using the treated water in its operations as well as making it available to the city for other “graywater” purposes.

In addition, the industry is exploring a variety of products that use either less or no water at all for fracturing shale. For example, a New York technology company has filed for a patent on a technique that would use natural gas itself to fracture the shale, eliminating the need for water. And industry suppliers also are making great strides in new water treatment technologies.

Protecting the groundwater

Fracking usually takes place thousands of feet below the earth’s surface – and below groundwater, as well. That’s why scientists are confident that fracking itself does not threaten underground drinking water supplies.

A 2015 Environmental Protection Agency report found no evidence that hydraulic fracturing practices have had widespread systemic impacts on drinking water systems in the United States. The EPA’s five-year analysis assessed the full scope of water use in the fracking process.

However, it’s very important that other parts of the process be done properly to protect drinking water. The most important protection is steel and cement casing around the well where it passes through the groundwater.

This type of casing is used in every type of gas and oil drilling, whether or not fracking is involved. It prevents fluids and methane from leaking into groundwater. Casing standards have been developed over many years, and states regulate well construction.

In addition to following proper procedures during drilling and operations, responsible developers make sure old wells are properly closed down and capped off.

Wastewater management

As described above, flowback and produced water that comes out of wells after drilling contains salt, some naturally occurring heavy metals and a small amount of chemical additives. This water must be properly handled to avoid contaminating surface or ground water.

Drillers use storage tanks to confine wastewater. As an alternative, some drillers store waste water on site in large pits. These must be properly lined to prevent leaks.

Many drillers dispose of wastewater by trucking it to deep water injection wells. Other industries have been using wells like these for waste disposal for many years, and they are regulated by the U.S. Environmental Protection Agency. On rare occasions, these wells have been drilled into geologic faults, creating mild earthquakes. However, governments and the industry now have the knowledge and technology to avoid faults and prevent seismic activity associated with wells.

Chemical additives in fracking fluids

The chemicals used in fracking liquids are a source of environmental concern. While additives make up less than half a percent of the total volume of water – and much of these are non-harmful substances – chemicals are present in many fracking solutions. Regardless of how small the amount of additives, they must be kept out of surface and groundwater.

The content of fracking fluids concerns many people interested in natural gas production: in particular, they want more public information about fracking chemicals. For many years, producers of fracking fluids held back content data, claiming the information was proprietary. More recently, the industry has recognized the need to address these issues. Companies are taking several approaches:

  • Disclosing the content of fracking fluids. Fracfocus.org is a partnership between the Ground Water Protection Council and the Interstate Oil and Gas Compact Commission. More than 200 energy producers voluntarily register the fracking chemicals they use with Fracfocus, which makes the information public on its website.
  • Using cleaner chemicals. Drillers are working with product manufacturers to develop more environmentally friendly additives. For example, one of the nation’s largest gas producers will not use products that contain benzene or diesel.

NW Natural has not performed its own scientific or economic research on the impacts of fracking or gas production practices. The information in this section is derived from publicly available reports, studies and periodicals.