Wyoming’s Department of Environmental Quality (WDEQ) did not find evidence that hydraulic fracturing fluids from a nearby natural gas field rose to shallow depths for drinking water and irrigation supplies near the town of Pavillion in 2014, the state agency said on Nov. 7.
“Also, based on an evaluation of hydraulic fracturing history, and methods used in the Pavillion gas field, it is unlikely that [fracing] has caused any impacts to the water supply wells,” it added in a fact sheet accompanying the more than 80,000-page report.
WDEQ conducted a further investigation after the US Environmental Protection Agency said in a 2011 draft report that it found chemicals consistent with fracing and gas production in groundwater near the west-central Wyoming community (OGJ Online, Dec. 9, 2011). The draft report never implied that fracing was unsafe, an EPA official subsequently told a US House subcommittee (OGJ Online, Feb. 2, 2012).
In its June and August 2014 sampling of 13 water supply wells near Pavillion, WDEQ found no organic compounds, other than a pesticide and an ester used in flexible polyvinyl chloride plastics that is a common laboratory contaminant.
“Inorganic compounds that were found over applicable drinking water standards are generally associated with naturally occurring salts, metals and radionuclides,” it said. “Industrial applications may use some of these same compounds (e.g. oil and gas drilling mud contains chloride and potassium).”
All organic constituents identified in groundwater samples at concentrations less than drinking-water standards or comparison values may have come from many possible sources, including spills, oil and gas activities, agricultural chemical applications, and other residential and industrial uses, the agency said.
WDEQ also evaluated nearby oil and gas wells’ integrity and the historic use of surface pits in Pavillion gas field. “Gas in the Upper Wind River formation appears to have originated mainly from upward migration from deeper commercial gas-bearing zones, and evidence suggests that upward gas seepage (or gas charging of shallow sands) was happening naturally before gas well development,” it said.
“Some gas wells are experiencing slow gas seepage. The relative contribution of potential gas seepage along gas wells versus natural upward migration of gas is undefined and would be very difficult to quantify,” the report said.
Its recommendations for additional work called for:
• Expanded evaluation of identified groundwater constituents, including bacteria, which can cause palatability issues.
• Focused assessment of the potential for gas seepage along gas wells versus naturally occurring upward seepage of gas, as well as evaluating conditions that might allow the potential movement of gas and liquids from intermediate zones pressurized by gas into shallower water-bearing zones.
• Further evaluation of the surface pits and their potential impact on water quality. In addition, holding collaborative discussions between WDEQ and the Wyoming Oil & Gas Conservation Commission (WOGCC) to evaluate consistent criteria for the closure of pits affecting groundwater.
• Further evaluation of other potential sources of petroleum hydrocarbons such as drill cuttings disposal sites, petroleum storage tanks, and gas production and gathering facilities.
• Additional sampling for constituents associated with palatability issues, as well as for specific chemical constituents and other chemicals, as necessary to achieve lower method detection limits.
• Initiate uncompleted recommendations identified in the WOGCC Well Integrity Review Report and perform further evaluation of potential well integrity concerns for select gas wells. The WDEQ said that it also concurs with the WOGCC Pit Review Report recommendation that further investigation of numerous closed pits is needed.
• Recommend that EPA plug and abandon two monitoring wells it constructed in 2010 in accordance with Wyoming Water Quality Rules and Regulations Chapter 26, due to the potential hazard they pose in relation to groundwater supplies and physical safety.
WDEQ said its next steps will include a December public hearing in Riverton to provide an opportunity for interested parties to obtain clarification regarding information in the final report.
In a Nov. 10 statement, US Senate Environment and Public Works Committee Chairman James M. Inhofe (R-Okla.) said WDEQ’s investigation over several years put to rest EPA’s 2011 attempts to link fracing to groundwater contamination. “The industry’s innovation in recent years, coupled with states’ responsible oversight of their local natural resources has, been a principal foundation for economic recovery in the US,” he said.
“We are also on a path toward real energy independence due to the shale gas and oil revolution, bolstering our national security at a time when we face historic global instability,” Inhofe said. “This is in spite of the fear-mongering tactics by environmental activists behind the nonsensical keep-it-in-the-ground movement aimed at putting an end to fossil fuels. For these reasons I look forward to the Trump administration’s embrace of the robust benefits that accompany developing our domestic resources.”
Contact Nick Snow at [email protected].
