Drilling and hydraulic fracturing in the Barnett Shale used about 55 billion gallons of water between 1981 and 2012, according to a new study by the Bureau of Economic Geology at the University of Texas at Austin. As huge a volume as that appears, lead researcher Jean-Philippe Nicot said it's "not much in the grand scheme of the water cycle" in the 10,000-square-mile Barnett Shale region. While Nicot noted that water use for hydraulic fracturing can be a much bigger problem in drier areas with intensive energy development, such as West Texas' Permian Basin, hydraulic fracturing accounted for about 0.5 percent of total water use in the state in 2011. County by county, however, that percentage can vary widely, based on drilling activity compared to population and other water uses, such as municipal use, agriculture and industry. For example, in Tarrant County hydraulic fracturing accounted for about 2.2 percent of total water use in 2011, according to the study. But in sparsely populated Montague County, one of the busiest counties in the Barnett in recent years, hydraulic fracturing accounted for about 40 percent of total water use in 2011.
The study also looked at disposal of wastewater from hydraulic fracturing by underground injection, and found that the amount injected is even more than the amount of water used. Nicot said the Barnett Shale is "an anomaly" among shale fields in that a high percentage of injected water flows back, accompanied by naturally occurring groundwater produced along with the oil or natural gas. Only about 5 percent of this flowback fluid has been recycled for reuse, the study estimates.
-- Jim Fuquay