Produced water represents the single largest waste product associated with the oil and gas industry Produced water will continue to emerge with oil and gas throughout the life of the well, and in fracked wells will pick up fracking chemicals as it flows to the surface. While relatively uncommon, acidizing has recently gained popularity in more arid regions, such as California, where water is scarce.Īnother component of the wastewater, known as produced water, occurs naturally in the rock formation and is liberated during conventional and unconventional drilling. This so-called flowback tends to look a lot like the fracking fluid mixture.Īcidizing techniques to facilitate oil and gas extraction use a similar mix of chemicals but at higher concentrations, in the range of 6–18%. Much of the injected mixture resurfaces within the first 2 weeks after pressure is released on the well. The chemical mixture varies from well to well, and wastewater from a single well typically contains only a small fraction of the more than 1,000 known fracking chemicals.
These chemicals include known or suspected endocrine disruptors, carcinogens, and other toxicants.
FRACKED UTAH ROCK FORMATION FREE
The force of the injection causes fractures and fissures in low-permeability rock formations that allow trapped oil and gas to escape, and the proppant holds the fractures open.Ībout 1–2% of fracking fluid is a proprietary chemical mixture that performs a number of important functions in the fracking process, from increasing the viscosity of the fluid to keeping the mixture free of bacteria that could foul well passages. These fluids consist largely of water combined with sand or some other type of solid particle, called a proppant. Large volumes of fracking fluids are injected underground at high pressure. A single shale well may use 2–8 million gallons over its lifetime, depending on geological characteristics of the particular “play,” or formation, involved. In North Dakota’s Bakken shale alone, wastewater volumes more than doubled during the first few years of the fracking boom, from roughly 1.1 million gallons in 2008 to more than 2.9 million gallons in 2012. And the dramatic increase of fracking in places like North Dakota, Ohio, and Pennsylvania in the past decade has led to a rise in the total volume of wastewater produced. Geological Survey (USGS).Ī wealth of wastewater is produced by both conventional wells (those drilled in highly permeable rock formations) and unconventional wells (those that use hydraulic fracturing to extract oil and gas). “We know very little about the cumulative effects of these releases on the environment,” says Isabelle Cozzarelli, a hydrologist with the U.S. Researchers are now beginning to assess the potential impacts of these wastewater releases on the health of humans and the environment. In North Dakota alone, well operators have reported nearly 4,000 spills to the state since 2007. There are many potential pathways for this waste to enter surface and ground water, including spills from pipelines or tanker trucks carrying the waste, leakage from wastewater storage ponds or tanks at well pads or disposal facilities, and migration of subsurface fluids through failed well casings.īetween 20 more than 21,000 individual spills involving over 175 million gallons of wastewater were reported in the 11 main oil- and gas-producing states of Alaska, California, Colorado, Kansas, Montana, New Mexico, North Dakota, Oklahoma, Texas, Utah, and Wyoming. However, for tribe members on the reservation it raised questions about the potential health impacts of leaks and spills of drilling wastewater-questions that are echoed by environmental health researchers who are calling for a closer look at the waste stream produced by oil and gas extraction.īy some estimates, as much as 5% of all oil and gas wastewater produced in the United States is accidentally or illegally released into the environment. Tribal leaders say the spill never reached the drinking water plant intake. Less is known about the potential human health impacts of these briny releases. When wastewater from oil and gas extraction is accidentally or illegally released into the environment, the ecological impacts can be immediate and readily visible.
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