Water Use and Recycling
Across our operations, we aim to optimize our use of natural resources and minimize waste. Water efficiency is essential to the long-term viability of modern natural gas and oil production. The different geologic formations in which we operate dictate how much water must be used to extract the natural gas and oil. Water is primarily used for well development in two ways:
- Drilling Fluid — a mixture of clay and water is used to carry rock cuttings to the surface, as well as cool the drill bit and control underground pressure.
- Hydraulic Fracturing — a mixture of water, sand and chemical additives is injected into the target formation under pressure to create small fractures in the rock, allowing natural gas or oil to flow to the wellbore. Typical fracturing fluid in our Marcellus Shale operations contains more than 99 percent sand and water.
Along with our efforts to use water efficiently, we recycle and reuse process and produced waters where possible. In our Marcellus Shale operations, which accounted for 93% of our reserves and production in 2016, we recycle nearly 100% of the water generated by our drilling, completion and production operations. Of that, we typically reuse between 59% and 98% of the recycled water in our own hydraulic fracturing operations, based on water volumes used by the completions program. What we do not reuse ourselves is recycled by third-party beneficial reuse facilities. We do not discharge process water, fracturing water, or produced water to surface water bodies. However, any water not reused by the permitted third-party beneficial reuse facilities is treated for discharge to surface waters in strict compliance with their own NPDES permits or is properly disposed. Cabot regularly evaluates water recycling options in other areas of operations, and currently utilizes water-disposal pipelines and injection wells for wastewater disposal when recycling is not a viable alternative.
With operations in rural communities in Pennsylvania and Texas, the majority of our neighbors rely on groundwater wells as their primary supply of water. Protecting their access to clean, safe water is a top priority of Cabot. Our groundwater protection program includes performing water supply baseline sampling, ensuring gas well integrity, engaging with landowners and complying with federal, state, tribal and local regulations.
Cabot’s baseline sampling program in the Marcellus Shale was developed based on an evaluation of our operational activities and is consistent with guidance from the Marcellus Shale Coalition’s Pre-Drill Water Supply Survey protocol. During the well permit application process, we notify nearby landowners of our intent to drill a well and offer them the opportunity to have their drinking water source tested at our expense. We test water supplies for a predefined set of parameters, which include general water quality indicators, biological parameters, metals, dissolved gases and petroleum constituents. We use independent state-accredited laboratories for all our water testing and provide landowners with the results of the analysis. With the analytical package provided to the landowner, Cabot provides available United States Environmental Protection Agency (EPA) drinking water standards for comparison, as well as a link to the appropriate state environmental agency website for additional information on how to interpret the results.
Maintaining an effective barrier between our oil and gas wells and water supplies is critical to the protection of these resources. Underground water sources are typically found at depths of only a few hundred feet below the surface. To safely penetrate these shallow zones on our way to the deeper oil and gas reservoirs, our drilling operations are designed to comply with or exceed applicable laws and regulations for the protection of groundwater. Steel pipe, known as casing, is cemented into place at the uppermost portion of the well for the specific purpose of protecting groundwater. These layers of casing and cement not only protect groundwater, but are also important to facilitate efficient production of natural gas from the well.
Before hydraulic fracturing begins, the cased and cemented well is tested at pressures greater than those that will be used during fracturing operations. Additionally, we conduct a cement bond evaluation log using sound waves. This testing allows for an additional layer of reassurance that groundwater is protected. For more information about our drilling process, see this video.
Addressing Landowner Concerns
Cabot takes landowner and community concerns very seriously. We address each complaint or concern through internal and regulatory processes. If the complaint is related to water quality, Cabot coordinates with the appropriate regulatory agencies to evaluate water quality conditions to ensure any water quality concerns are properly addressed and resolved in accordance with all applicable regulations.
Chemical Disclosure (Frac Focus)
Much of our nation’s hydrocarbon supplies, including those owned by Cabot, are located in shale formations, which require fracture stimulation to develop. As such, hydraulic fracturing is critical to our operations. Our Policy on Hydraulic Fracturing Fluids documents our commitment to use the most environmentally benign hydraulic fracturing fluids that are available and effective to produce desired operational results. We understand the public’s desire to know more about what is involved in our hydraulic fracturing operations, so we voluntarily disclose the chemicals used in hydraulic fracturing fluid in 100% of our hydraulically fractured wells through www.fracfocus.org.