The answers to all your fracking questions
Just kidding. But it's a good start.
The debate over ‘fracking’
Public discussion of hydraulic fracturing is extremely polarized, and people seeking “just the facts” often find themselves sifting through heated rhetoric, unable to distinguish between bias and balance. Advocates claim that hydraulic fracturing creates jobs, fosters energy independence, and actually has environmental benefits. Critics say that fracking contaminates drinking water, hurts local environments, and carries risks that outweigh potential benefits. UNCG undergraduate Peter Hess, an Environmental Studies major, spoke to UNCG geography faculty Dan Royall and Corey Johnson to try to find some clarity.
What exactly is it?
Hydraulic fracturing, or fracking, is the process by which companies extract difficult-to-access oil and natural gas from deposits deep below the earth’s surface. These deposits are held tightly in rock formations consisting of shale, an impermeable type of rock. Fluids cannot move freely within or out of the shale unless it is fractured.
Normal drilling for oil and gas is simpler. Typically, the fuels migrate upward from a source rock that has been fractured by some natural mechanism (like faulting), until they reach a layer of impermeable rock. The oil and gas form a pocket, or trap, beneath the impermeable rock, and companies drill through the rock to access them. Fracking for oil and gas in shale formations is not so easy. “With fracking,” explains associate professor Dan Royall, “we must do the fracturing of the source rock ourselves.”
“The type of oil shale that is tapped with fracking is different. It can be very deep and not form any natural trap,” says Dr. Royall. Fracking involves drilling both vertically and horizontally, blasting water through layer after layer of shale. To drill, engineers inject fluid, made up of water and “proppants” such as sand or ceramic beads, at immense pressure deep underground. The water pushes through the shale, while the sand or ceramic holds these new fractures open to allow gas and oil to escape. At the end of the process, the fluid comes back up to the surface where it is stored in surface wells or injected into underground storage wells.
Is it dangerous?
Dr. Royall notes that, if all goes according to plan, fracking poses no threat to drinking water. Fracking takes place so far below the water table that it is unlikely that methane (the chief component of natural gas) or fracking chemicals (more on these later) will rise up from disturbed shale gas deposits to contaminate drinking water in aquifers.
But how likely is it that everything will go according to plan?
One of the biggest factors of unpredictability is the concrete casing that surrounds the vertical pipe in the fracking well. Once fracking fluid has cracked open oil and gas deposits, it flows back up the pipe, followed by the oil and gas. As the fluid and gas return to the surface, explains Royall, “if that pipe or the casing is cracked in some way and there is a leakage, then that material can move directly into the shallower groundwater.” According to associate professor Corey Johnson, “drillers are working partially blind — it is hard to know, for example, whether the concrete lining dried properly and is free of cracks.” In a deep drilling operation, it is difficult or even impossible to account for and inspect every inch of pipe casing.
Errors such as these account for many of the horror stories in the media around fracking. For example, residents near fracking sites in Pennsylvania have experienced well water contamination by methane. Some homeowners can even set their tap water on fire.
However, it has been difficult to prove contamination is from fracking. “A person can claim that their water has been contaminated by fracking,” says Dr. Royall, “but a mining company can say ‘no, that comes from a natural source, or it was there all along, or it wasn’t us.’ There is a need for finding some kind of technique that will allow you to fingerprint or uniquely associate contamination from fracking from other potential sources of contamination.”
This year, Duke University researchers and others have begun to address these problems. By measuring boron and lithium isotopes in water, they can determine whether water that has contaminated well water was used for fracking. With this method, voices on both sides of the debate might get clear answers about the safety of runoff from fracking operations. Another study by researchers at Duke University and four other universities used noble gas tracers to show that when methane contamination of water wells did occur, it did so by leaking from cracked pipe casings and not by drifting up from the fracked gas deposits. This study supports Dr. Royall’s assertions on methane contamination and highlights the need for rigorous testing and monitoring of the equipment used for hydraulic fracturing operations.
In addition to water contamination concerns, a recent study conducted by Dr. David Carpenter, director of the Institute for Health and the Environment at the University at Albany – State University of New York, suggests that the process of fracking may result in dangerous levels of air pollution. Researchers found that levels of benzene, formaldehyde, hydrogen sulfide, and five other chemicals exceeded federal guidelines near drilling sites.
Scientists have also linked fracking to increasing numbers of small earthquakes.
What’s in the fluid?
A major public concern is the contents of fracking fluid. Water and sand alone are not sufficient for the task of cracking shale and holding it open. Chemicals such as hydrochloric acid help dissolve minerals and initiate cracks in the shale. Others like sodium tetraborate help the water retain its viscosity under extreme heat and pressure. Still others, such as tetrakis hydroxymethyl-phosphonium sulfate, are anti-bacterial agents.
What exactly are we putting in the ground? What could leak into our water as a result of human error? What kind of runoff is coming from surface wells storing fracking fluid? Unfortunately, the public does not know. Companies vigorously defend the proprietary formulas of their fracking fluids, leaving the public with no exact knowledge of their composition. To critics, industry reluctance to disclose the chemicals is a de facto admission that the chemicals are unsafe.
Is it worth it?
Fracking allows us to exploit fuel deposits that used to be prohibitively expensive to access. Increased access to natural gas could lead to decreased dependence on foreign petroleum sources, as well as creation of more jobs in the fossil fuel extraction industry.
More natural gas usage could mean less coal usage in industry and residential energy production. Natural gas burns more cleanly than coal, producing fewer toxic byproducts. Natural gas also emits much less carbon dioxide than coal does, so fracking could curtail American contributions to global warming.
Fracking could have positive social, economic, and environmental benefits. But those benefits balance on two major factors.
The first factor is risk. Geography varies, human error happens, and both can contribute to accidents in fuel extraction operations. Even small mistakes can create large problems. Recent examples include BP’s Deepwater Horizon spill and, locally, the coal ash spill in the Dan River. In both situations, seemingly small flaws produced devastating impacts. With regards to energy, says Dr. Royall, “A lot of times we accept the downside as well as the good. A lot of times we don’t see the downside until we see it – until it happens. And then sometimes it’s kind of too late. That’s the issue.”
Is the risk worth it? To even begin to address that question, we come to the second factor. How do we know what fracking is worth? Unfortunately, that also varies – by time and geography. Prices for natural gas wax and wane, leaving future industry demand for fracking uncertain. The amount of fuel in a particular reserve is also uncertain.
“Prices for natural gas are currently low, slightly up from historic lows a year or so ago. Simple supply and demand curves still matter,” says Dr. Johnson. “We still don’t know how much gas is recoverable, and the harder it is to frack the gas, the less likely industry players are to want to invest [in North Carolina]. We have very little data to go by, so once test well results are available we’ll know more.”
If tests come back favorably, our state will have to ask itself some very difficult questions.
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Main article photo by Ostroff Law, available under Creative Commons Attribution 3.0 Unported license.
Article author Peter Hess is an Environmental Studies intern working with the UNCG Office of Research and Economic Development. His writing focuses on the important research being conducted by members of the UNCG community. Peter is an environmental studies student in his senior year at UNCG. His passion for communicating science to the public led to his current position.