“A well’s wastewater is comprised chiefly of brines extracted with the gas and oil from deep underground, blended with some of the water initially injected into the well during hydraulic fracturing. These brines are typically salty and may contain toxic and naturally occurring radioactive elements, making them difficult to treat and dispose of safely. To keep up with the growing volume of wastewater now being generated, drilling companies increasingly are injecting it back deep underground into wastewater wells. This practice helps keep the wastewater out of local water supplies but has been linked to small- to medium-sized earthquakes in some locations.”
Fracking use of water has increased 770% over the last 5 years—and that’s just the beginning
Previous studies have suggested that hydraulic fracturing does not use significantly more water for exploration and production than other energy sources (fig. S4) and, at the same time, indicated that water use for hydraulic fracturing makes up only a small fraction of the industrial water utilization in the United States (7, 22, 23, 33). These evaluations were based on aggregated water footprint data during the early years (2011–2014) of hydraulic fracturing in the United States. Here, we show, however, steadily increasing volumes of water use with time in all the major unconventional gas and oil regions (Fig. 2 and tables S1 and S2). Parallel to the increase of shale gas and tight oil production intensity, we also show that the water intensity of hydraulic fracturing is increasing for both unconventional gas and oil regions (Fig. 4 and tables S3 and S4). In addition, the water used for hydraulic fracturing is retained within the shale formation; only a small fraction of the fresh water injected into the ground returns as flowback water, while the greater volume of FP water returning to the surface is highly saline, is difficult to treat, and is often disposed through deep-injection wells. This means that despite lower water intensity compared to other energy resources (fig. S4), the permanent loss of water use for hydraulic fracturing from the hydrosphere could outweigh its relatively lower water intensity.
The period of 2014–2015 marks a turning point, where water use and FP water production began to increase at higher rates. During this period, gas and oil prices dropped significantly, causing producers to scale back the number of new installed wells (Fig. 5 and tables S1 and S2). In each of the oil-producing regions, the water use/oil production ratio increased, suggesting that the increase in water use for hydraulic fracturing outpaces the increasing oil production on a per-well basis (Fig. 4, fig. S2, and table S2). In the shale gas–producing regions, this trend is also present, but not as strongly apparent as with the unconventional oil-producing regions (Fig. 4, fig. S2, and table S1). Consequently, while increasing lateral length of horizontal drilling and water use for hydraulic fracturing (Fig. 2) have resulted in increasing oil production (per well), the net water-use efficiency, particularly for unconventional oil production, has decreased (that is, higher water intensity).
And so while fracking operations have become more “efficient,” their overall impact on the environment has increased dramatically. The jump in brine wastewater is terrifying, as one of the largest issues surrounding fracking and its impact on the environment is specifically how wastewater is managed.
A well’s wastewater is comprised chiefly of brines extracted with the gas and oil from deep underground, blended with some of the water initially injected into the well during hydraulic fracturing. These brines are typically salty and may contain toxic and naturally occurring radioactive elements, making them difficult to treat and dispose of safely. To keep up with the growing volume of wastewater now being generated, drilling companies increasingly are injecting it back deep underground into wastewater wells. This practice helps keep the wastewater out of local water supplies but has been linked to small- to medium-sized earthquakes in some locations.
Fracking has already been connected to deleterious effects on drinking water. The authors of the study hope that it can provide officials, not just in the United States but around the world, guidance on the impact to the environment that fracking operations can and will continue to have.