As the cost of recycling wastewater falls, it could emerge as the preferred method for addressing many of the water-related environmental concerns surrounding hydraulic fracturing.
Hydraulic fracturing generally requires vast amounts of fresh water. Estimates vary widely, but water used for a fracturing job ranges from 40,000 to 60,000 bbls in the Delaware Basin, according to a Society of Petroleum Engineers paper authored by engineers from Halliburton and ExxonMobil subsidiary XTO Energy. Other sources, such as ALL Consulting, estimate per-well water use as up to 5 million gallons.
Common methods of disposing of water used in fracking include treatment and discharge to surface waters, deep well injection, storage in open-air pits and use on roads for ice or dust control, according to the Natural Resources Defense Council (NRDC). Various technologies also exist to clean flowback water so that it can be reused to drill other wells.
Oil and gas companies are under mounting pressure to address numerous water-related environmental concerns. These include the use of what may be scarce freshwater resources, especially in dry areas; truck traffic (with attendant emissions, road damage and noise pollution) to transport water from well sites to treatment or disposal sites; and the potential migration of contaminants from deep injection wells to nearby aquifers.
Of the above-listed wastewater disposal options, the NRDC says that only recycling and deep well injection should not be banned immediately.
Recycling flowback water has some advantages over injecting it into disposal wells. In addition to mitigating water scarcity and truck traffic concerns, disposal wells have also been linked to earthquakes in areas such as Ohio. Recycling can also be used for produced water, which comes out of the wellbore along with hydrocarbons, and flows continuously over the life of the well. This could offer further conservation possibilities.
Deep well injection has traditionally been the most cost-effective option, but oil and gas companies are not in a position to ignore public concerns over the impact of drilling on the environment, increasingly citing the need to maintain a “social license” to operate. “With the lack of fresh water availability in arid climates, it’s not only a pricing issue, but a water availability issue,” Ecosphere Energy Services Chief Executive Robbie Cathey told Breaking Energy.
“There’s no way they can just walk over these environmental issues, they’re going to have to address them very aggressively,” said Riggs Eckelberry, Chief Executive of advanced biofuels firm OriginOil.
Companies such as Ecosphere and OriginOil have developed various recycling techniques, with each company saying that its process is cost-competitive with injection into disposal wells. For more on these techniques, see part two of this three-part series: How It’s Done: Cleaning Up Fracking Wastewater.