New Duke Study Finds “Low” Risk of Flowback Contaminating Water

Duke University researchers recently published a new study, which finds the volume and quality of water that returns to the surface during oil and natural gas development (which the study refers to as “FP water”) is almost entirely composed of naturally occurring formation brine (about 92 to 96 percent), with between four and eight percent of wastewater consisting of fracking fluid used in development. Even then, the study finds, fracking fluid is only found within the first few months of development.

Because much of the FP water is formation brine, the authors mention it can be safely processed and reused depending on its salinity and chemical composition. FP water that is unable to be recycled is therefore re-injected back into the formation, a practice used for decades and described by the U.S. Environmental Protection Agency as a “safe and inexpensive option” for the disposal of hazardous byproducts.

In short, this is yet another study that confirms oil and gas development is safe. In fact, one of the lead researchers – Avner Vengosh, who has produced a number of anti-fracking studies over the years – had to admit that the risk of contamination from this process is very “low.” From the press release:

This means that the probability of having environmental impacts from man-made chemicals in fracking fluids is low, unless a direct spill of the chemicals occurs before the actual fracking.” (emphasis added)

Vengosh explains why this is the case noting,

“‘Much of the public fear about fracking has centered on the chemical-laden fracking fluids – which are injected into wells at the start of production – and the potential harm they could cause if they spill or are disposed of improperly into the environment […] Our new analysis, however, shows that these fluids only account for between 4 and 8 percent of wastewater being generated over the productive lifetime of fracked wells in the major U.S. unconventional basins…Most of the fracking fluids injected into these wells do not return to the surface; they are retained in the shale deep underground.”

Not only does the study find the process is safe, it also highlights the benefits of water recycling. The study found that since different formations produce FP with different constituents and salinity levels, water produced in some areas need little processing before it can be used. This is true for much of the water produced in Western formations, as the study states:

“Based on these variations, we estimate that the western basins (Niobrara, California, Eagle Ford) with relatively low salinity in the formation brines have more potential for reuse for hydraulic fracturing and/or beneficial uses.” (p. 320)

The beneficial uses mentioned by researchers include reuse for development, thus cutting down on the already relatively small amount of water used for hydraulic fracturing, as well as irrigation for crops. Both of these are especially important in areas with water scarcity, such as California, where programs that use recycled produced water to irrigate farmland have been proven to be safe. As one researcher mentioned in the study’s press release:

“But with proper treatment, they [FP water] potentially could have beneficial uses…especially out West, where our study shows most brines being produced by fracked wells are much less saline than those in the East. These Western brines, which are similar to sea water, could possibly be treated and re-used for agricultural irrigation or other useful purposes, especially in areas where freshwater is scarce and drought is persistent.”

Despite these findings however, some opposed to oil and gas development may latch on to the section of the report that states,

“The management and disposal of flowback is one of the greatest challenges associated with unconventional oil and gas development.” (p. 314)

But, if the study clearly states that the management of FP water is safe and the risks are “low,” and that’s “one of the greatest challenges” associated with fracking, that’s a pretty darned good track record.

Overall, this study reaffirms that not only do the additives used in hydraulic fracturing not pose a significant environmental risk, but also that much of the water produced during development is in fact naturally occurring formation water that can be safely redisposed back into the formation. Moreover, the authors find that some of this produced water can be recycled for use in more development or irrigation, helping those regions impacted by water scarcity.


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