High rates of saline wastewater production by hydraulic fracturing (HF) activities have resulted in environmental and water management concerns. In this study, a comprehensive database containing more than 800,000 wells in Canada was assembled to investigate play-scale wastewater production by HF operations. We found that nearly 13% of the HF wells and only about 1% of the conventional wells produce &gt;5,000 m3 of wastewater during the first six months of their production. After approximately one year of production, the average monthly produced wastewater from a conventional well exceeds that produced from a HF well, however a typical HF well generates about twice more wastewater after two years of production compared with an average conventional well. Estimates suggest that by 2030, HF wastewater will likely comprise ~60% of the total produced in the Montney play, Canada, up from approximately 30% at present. Data analysis also indicates that, for the Montney, wastewater from HF wells is generally more saline than that produced from conventional wells; during the first six months of production, more than 50% of HF wells and less than 2% of conventional wells have produced wastewater total dissolved solids over 50,000 ppm. Moreover, a typical HF well generates, on average, 770 tons of salts after two years of production, which is approximately 4.5 times higher than that produced by a typical conventional well. Estimations indicate that more than 20 million tons of salts can be produced in the Montney play by 2030, and with the current pace of HF growth, ~80% of the total produced salts (TPS) in the play will be generated by HF wells. As much of the potential environmental toxicity of produced wastewaters is due to salinity, we suggest that TPS may be a valuable metric for regulators, operators, and environmental groups to track when assessing risk and evaluating water treatment strategies.

Wastewater production footprints of hydraulic fracturing operations: Current pace and future impacts

2019 Fall National Meeting

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