Flammable tapwater often not because of industry gas leaks, CU study finds


Methane natural gas has dissolved into groundwater at 64 percent of the sites state regulators tested since 1988 in northeastern Colorado, University of Colorado researchers have found. But more than 95 percent of this gas came from naturally occurring microbial processes, often near shallow underground coal seams — not the oil and gas industry. Methane-tainted groundwater can lead to flammable drinking water pouring out of household taps. The CU study, funded by the National Science Foundation and based on an analysis of Colorado Oil and Gas Conservation Commission records, concluded that the industrial process of hydraulic fracturing, or fracking, is not a primary cause of methane contamination of groundwater. Methane leaking from oil and gas well bores contaminates groundwater about two times a year on average. And the CU researchers found that rate has stayed about the same since 2001. From 2001 through 2014, dissolved methane linked directly to geological formations holding oil and gas reached 42 water wells in 32 cases, the researchers found. The findings have been published in the Proceedings of the National Academy of Sciences journal. A boom in oil and gas production across northeastern Colorado, using fracking to stimulate production and horizontal drilling starting around 2010, has raised concern about contamination of groundwater due to leakage from oil and gas well bores. Opponents have circulated videos of tap water that could be ignited. At 924 water wells where COGCC regulators conducted tests, methane was detected in 593 wells, the study found. The researchers relied on ratios between carbon and hydrogen stable isotopes and gas molecules to determine that most of the methane in groundwater came from microbes within shallow coal seams. They said the industrial leaks involved inadequate surface casing. Older gas wells, drilled in the 1970s, typically were cased to a depth of about 300 feet, leaving groundwater aquifers vulnerable to contamination from leaks. Companies today are required to case wells to deeper levels and repair older wells.



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