Contrary to earlier federal reports, hydraulic fracturing (fracking) fluids were not a factor at shallow depths intersecting groundwater supplies at Pavillion, WY, according to a draft final report from the Wyoming Department of Environmental Quality (DEQ).
While there were both some inorganic and organic compounds found above acceptable levels for drinking water, none of the fluids associated with fracking were found to have migrated upward to shallower depths.
The draft state report is the result of an ongoing investigation by Wyoming into drinking water quality concerns near Pavillion area gas wells that first drew focus more than four years ago in the wake of two federal Environmental Protection Agency (EPA) test wells (see Shale Daily, Dec. 9, 2011). Back then, EPA alleged that the groundwater in Pavillion, WY, contained chemicals that are normally used in natural gas production practices, such as hydraulic fracturing.
EPA subsequently backed away from that conclusion, and the state took the lead two years ago in conducting further tests through its DEQ (see Shale Daily, June 24, 2013).
Based on the Wyoming DEQ's June and August 2014 sampling of 13 water supply wells, no organic compounds were identified above applicable drinking water standards, except for a pesticide (beta-BHC) and Phthalate, a plasticizer used in flexible PVC plastics.
"All organic constituents identified in groundwater samples were at concentrations less than drinking water standards or comparison values may have originated from a multitude of possible sources, including spills, oil/gas activities, and other residential/industrial uses," said the DEQ draft report as released last Friday. "Inorganic compounds that were found over applicable drinking water standards are generally associated with naturally occurring salts, metals and radionuclides."
The 127-page draft said that there is no evidence indicating "that hydraulic fracturing fluids have risen to shallow depths intersected by water supply wells," and that based on the drilling history of the Pavillion gas field, "it is unlikely that fracturing has caused any impacts to the water supply wells."
Wyoming's latest report undercuts EPA's original findings and substantiates the concerns of state officials that questioned the science used in the EPA studies.
Gov. Matt Mead, who came into office in the midst of the controversy between the state and EPA, has said he wanted "an unbiased, scientifically supportable conclusion" regarding the Pavillion water wells (see NGI, Nov. 14, 2011).
Before Mead was governor, the federal EPA was approached by Pavillion residents in 2008 with concerns about adverse changes to the area drinking water. After meeting with the state DEQ, EPA began sampling drinking water wells in 2009; a second sampling took place the following year. Based on the results, EPA installed two monitoring wells to assess conditions deeper in the aquifer and sampled the monitoring wells and selected drinking water wells in October 2010 and again in April 2011.
DEQ Director Todd Parfitt said the draft report, which will now undergo public comment, eventually is viewed as completing a "scientifically supportable" final report. Comments will be taken for a 90-day period ending March 18 next year.
Aside from the finding on fracking, the draft report explains some of the concerns about the water well quality, noting that:
Gas in the Wind River Formation appears to have originated mainly from upward migration from deeper gas-bearing zones;
Evidence suggests the upward seepage was happening naturally before drilling;
Some gas wells are experiencing slow gas seepage that could possibly have caused changes in water quality; and
The presence of bacteria in many of the water-supply wells suggests that this may be a cause of taste and odor issues.
"This draft report is part of an extensive scientific investigation to better understand what may be contributing to private water well concerns,” Parfitt said.