In the early days of the shale-gas boom that is now at full throttle around the U.S. and the globe, speculators rushed into hydrofracking with high hopes, often with little attention to how much water would be needed or the best practices for managing the water when they were done with the wells. You might say it was a little like the wild, wild West. "Early on, there was little concern and not a lot of regulation about how water was sourced" and how flowback was handled, says one industry insider, who asked not to be identified due to the nature of his comments. "Originally, there were probably a lot of mistakes made."
Researchers at the PennEnvironment Research & Policy Center, Philadelphia, found that, of the 4,596 fracking sites operating in Pennsylvania between 2008 and 2011, companies operating there violated environmental laws 3,355 times, based on the state's Dept. of Environmental Protection enforcement actions. Violations ranged from improper erosion and sedimentation plans to faulty pollution-prevention techniques.
But times—and the engineering behind hydrofracking operations—are changing.
Many construction and engineering industry sources say the shale-gas boom is evolving. New technologies, along with a commitment by many energy companies and operators to do a better job of managing the resources that go into the extraction of shale gas, are pushing the industry to a more sophisticated, environmentally conscious place.
"You are seeing a lot of evolution in all areas of the development" of shale gas, says C. Hunter Nolen, president of the industrial services group at Cambridge, Mass.-based CDM Smith. "From technologies of drilling and hydraulic fracturing to techniques in water management to the evolution of regulatory drivers—all sorts of things are changing rapidly."
The improvements could help the public image of an industry that has environmental groups opposed to its growth on many fronts, particularly its potential harm to wells and aquifers near fracking fields.
New York and Maryland have imposed moratoriums on the practice until environmental safeguards, such as better water management rules, are in place. Citizen groups in Pennsylvania and New York have filed lawsuits to halt the spread of fracking wells.
As a result, the industry often is described as a "black swan"—that is, a boon for jobs amid a deep recession but also a development that changes everything, leading to many unknowns, says industry veteran John H. Pinkerton, executive chairman of Range Resources, Fort Worth, Texas.
Fracking involves blasting large amounts of water mixed with chemicals deep into the ground to crack open naturally occurring fissures in shale formations. Then, a proppant—a substance, usually sand—is used to keep open the shale fracture. The process helps operators economically extract natural gas and oil that, previously, were not easily collected.
According to the Energy Information Administration (EIA), since 2006, dry shale-gas production in the U.S. has increased to 4.8 trillion cu ft from 1.0 trillion cu ft, which equals 23% of total U.S. dry natural-gas production in 2010. The EIA adds that wet shale reserves are at their highest levels since 1971.
While fracking allows for new depths of natural gas and oil to be plumbed, the technique requires huge amounts of water. An average well takes between three million and seven million gallons of water for each fracking job, according to the U.S. Geological Survey. Wells can be fracked multiple times. In areas where supplies of freshwater—streams, rivers, reservoirs—are scarce, water usage for fracking has become a drain on natural resources.
That concern and its related costs have driven many operators to move toward recycling produced and flowback water, says CDM's Nolen. "Recycling has become a very important aspect of water management in the shale arena," he says, in areas such as Pennsylvania, where deep injection wells are not widely available, and in areas such as Texas, where sources of freshwater are limited.
Jim Kolhaas, vice president of strategic energy programs for McLean, Va.-based SAIC, notes that while flowback rates vary widely depending on location and geology, the amount of water that flows back after a frack job could total millions of gallons of water. Recycling results in "a significant re-use and reduction of pressure on the freshwater system," he says.
Before the water is re-used, it receives at least minimal treatment, says Kelvin Gregory, associate professor of engineering at Carnegie Mellon University in Pittsburgh. He says treatment typically involves precipitation and coagulation to remove divalent cations, such as barium, strontium, calcium and magnesium, which are often present in the flowback water.
Or, some operators may use reverse osmosis to recycle the water, but that can be expensive. Further, that method isn't really necessary for water that will be used for another frack job, he adds.
In cases in which the water needs to be discharged to a surface water source, such as a river or stream, reverse osmosis or other advanced treatment technology become more necessary, says Nolen. However, when salt concentrations are very high, as they typically are in the Marcellus shale region that spreads over Pennsylvania and New York, reverse osmosis may not be sufficient. Firms must look at other technologies, such as evaporation, Nolen says, but "evaporation is very expensive. It really is a treatment of last resort."
Alternative Sources of Water
Operators increasingly are looking at alternatives to freshwater to pump into the ground with the chemicals and proppant. Sources include brackish water, particularly prevalent in Texas, and abandoned mine drainage (AMD) water. The potential for AMD water as an alternative to freshwater for fracking use is generating excitement in the shale-gas industry.
Abandoned, or "orphan," mines are a large source of surface-water contamination in the northeastern U.S. Most of the firms that operated them—generally before more stringent mining regulations kicked in during the 1970s—have gone out of business, and the water that drains from the mines is often contaminated.
In Pennsylvania alone, there are approximately 2,400 miles of streams polluted with AMD water, many of them near fracking sites.
Pools of mine water have flow rates that usually range from a half-million gallons a day to 1.5 mgd. They have varying concentrations of iron, from one part per million to 100 ppm, as well as aluminum, manganese and sulfates, which range from 50 ppm to 1,000 ppm.
Although operators of active mines now treat their water, the Pennsylvania Dept. of Environmental Protection (DEP) has limited resources to treat the water that drains from orphan mines and pollutes local streams and rivers.
According to a number of sources, using AMD water in fracking could benefit both the environment and fracking operators. They say that using treated AMD in so-called makeup water would reduce metal loadings and pollutants in watersheds while at the same time reduce the use of "clean" water for fracking.
Carnegie Mellon's Gregory is working with the University of Pittsburgh on a study of the chemistry of mine water mixing with flowback water from fracking. While he has not concluded definitively that AMD could work with fracking, he says it offers significant potential. "Philosophically speaking, you could say this is a way [fracking] could possibly improve the environment by removing, at least temporarily, the sources of contamination into our surface waters," he says.
Pasadena, Calif.-based Tetra Tech worked on a project in South Fayette Township, Pa., with the Pennsylvania DEP, the South Fayette Conservation District and Range Resources to develop a plan to use AMD water from a local mine. The plan involved treating the water, then pumping the treated water to impoundments at wells and discharging excess water to the stream. However, the well operator stopped drilling at the site before the project could be executed.
There are drawbacks, too. State regulations typically require firms that take on water treatment to be responsible for the mine in perpetuity, Gregory says. The liability issues alone could make some firms pause.
In Pennsylvania, state lawmakers have drafted legislation that would remove this obstacle, but the measure isn't expected to come to a vote before next year, notes Stephen Hughes, water management manager, Tetra Tech.
The Pennsylvania DEP has written a white paper that provides some guidance on using AMD water in fracking operations.
Further, some energy services firms, engineers and manufacturers are working to develop extraction methods that use little water or none at all. "There's an era coming up of the waterless frack job," says SAIC's Kolhaas. (For more information on some of the new technologies being developed, see sidebar.)
Water has become so central to fracking development that engineering firms increasingly are advocating that operators develop water master plans that consider the water life cycle as it relates to the development plan for sites. "We see this as an important step for operators to take … because water has become such an important aspect of successful shale development that a good, thoughtful, comprehensive master plan is [essential]," Nolen says. "I think we have a way to go before that is a built-in culture, but water planning is becoming an important piece of development."
For example, as part of an overall water plan, some companies are adjusting their schedules according to seasonal variability in flow rates, so that they are less likely to deplete sources of water.
From individual operators to the American Petroleum Institute and the National Groundwater Association, organizations have developed best management practices as a way to improve safety at fracking sites. "I would say that, on the upstream side, we're in the process of normalizing industry best practices, so everybody does a good job, not just some people," Kolhaas says. One practice that many support is to perform baseline groundwater sampling from a radius of a quarter mile to three-fourths of a mile around a future drill site. Julie Sueker, a geologist and an associate vice president at Netherlands-based Arcadis, recommends conducting baseline sampling several times prior to drilling as water quality can vary depending on the season. If a problem does develop and stray gas migration is suspected, then more sampling can be done and steps can be taken to remediate the problem, Sueker says. Groundwater sampling is also one of the practices recommended by the Dept. of Energy in its guidance released in 2011.
The Environmental Protection Agency is in the midst of a major study on the impacts of hydraulic fracturing on water. EPA plans to release a progress report at the end of 2012; a final report, which will include several case studies, is due in 2014.
"There certainly have been occasions where industry has not followed best practices or the guidance. I think you'll see some of that coming out in the EPA report that drives future change," says Darryl Shoemaker, director of energy services at Omaha, Neb.-based HDR. "I think you can expect they'll have zeroed in on instances where the development didn't occur as planned, and that's something industry is going to have to grapple with going forward."
But environmental activists point to examples in which drinking-water wells have been potentially contaminated as a result of mistakes or miscalculations made during the production process. The suspected causes of problems include sloppy work on drilling and casing wells and spills from transporting frack flowback and produced water to and from project sites, says Kate Sinding, senior attorney with the Natural Resources Defense Council.
HDR's Shoemaker notes that many other industries have had their own learning and acceptance curves, which fracking appears to be undergoing. "I think if you look at how some of those other segments have evolved, I don't think it's a question of if they'll get to a point where … it matures and has a better fit into the social and natural environment. I think it's a question of when."