Spatial and Temporal Correlation of Water Quality Parameters of Produced Waters from Devonian-Age Shale following Hydraulic Fracturing

• Published in: Environmental science & technology 2013-03, Vol.47 (6), p.2562-2569
• Main Authors: Barbot, Elise, Vidic, Natasa S, Gregory, Kelvin B, Vidic, Radisav D
• Format: Article
• Language: English
• Subjects: Applied sciences; Cations - analysis; Chlorides - analysis; Comparative analysis; Correlation analysis; Crude oil, natural gas and petroleum products; Earth sciences; Earth, ocean, space; Energy; Engineering and environment geology. Geothermics; Exact sciences and technology; Fossils; Fuels; Hydraulics; Industrial wastewaters; Oil and Gas Fields - chemistry; Pollution; Pollution caused by production, transportation and treatment of oil and oil shales. Water and soil pollution. Treatments. Pollution control; Pollution, environment geology; Salts - analysis; Waste Water - analysis; Wastewaters; Water Pollutants, Chemical - analysis; Water Quality; Water resources management; Water Supply - analysis; Water treatment and pollution
• ISSN: 0013-936X; 1520-5851
• DOI: 10.1021/es304638h

The exponential increase in fossil energy production from Devonian-age shale in the Northeastern United States has highlighted the management challenges for produced waters from hydraulically fractured wells. Confounding these challenges is a scant availability of critical water quality parameters for this wastewater. Chemical analyses of 160 flowback and produced water samples collected from hydraulically fractured Marcellus Shale gas wells in Pennsylvania were correlated with spatial and temporal information to reveal underlying trends. Chloride was used as a reference for the comparison as its concentration varies with time of contact with the shale. Most major cations (i.e., Ca, Mg, Sr) were well-correlated with chloride concentration while barium exhibited strong influence of geographic location (i.e., higher levels in the northeast than in southwest). Comparisons against brines from adjacent formations provide insight into the origin of salinity in produced waters from Marcellus Shale. Major cations exhibited variations that cannot be explained by simple dilution of existing formation brine with the fracturing fluid, especially during the early flowback water production when the composition of the fracturing fluid and solid–liquid interactions influence the quality of the produced water. Water quality analysis in this study may help guide water management strategies for development of unconventional gas resources.