Water Use and Recycling
Across our operations, we aim to optimize our use of natural resources and minimize waste. Currently, all of Cabot’s operations are related to natural gas extraction within the Marcellus Shale and efficient use of water is essential to the long-term viability of modern natural gas production. The geologic formation in which we operate dictates how much water must be used to effectively extract the natural gas. Water is used primarily 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 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, we recycle nearly 100% of the water generated by our drilling, completion and production operations. Recycled water that we do not use in our operations is managed 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 National Pollution Discharge Elimination System (NPDES) permits or is properly disposed.
With operations in rural communities in Pennsylvania, 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 surveys and sampling, ensuring gas well integrity, engaging with landowners and complying with federal, state, and local regulations.
Cabot’s baseline sampling program in the Marcellus Shale was developed based on an evaluation of our operational activities and exceeds guidance from the Marcellus Shale Coalition’s Pre-Drill Water Supply Survey recommended practice. 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 water resource supply tested at our expense. We test water supplies for a predefined set of parameters, which include general water quality indicators, 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. Soils and overburden at the surface are protected and isolated by a steel conductor pipe, which is cemented into the bedrock as a standard practice to provide an anchor for drilling operations and to provide protection for shallow surface water and soils. Multiple strings of steel pipe, known as casing, are then cemented into place as each well section is drilled. The sections at the uppermost portion of the well are designed to provide specific protection for groundwater sources while later sections provide an isolated conduit for production.
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 using sound waves. Any anomalies observed during these tests are evaluated and necessary pre-emptive measures are taken to ensure wellbore integrity. This testing allows for an additional layer of reassurance that groundwater is protected.
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 relates to water quality or diminution, Cabot coordinates with the appropriate regulatory agencies to evaluate the water supply conditions to ensure any water supply concerns are properly addressed and resolved in accordance with all applicable regulations.
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.