Possible contaminant found in gas well pits near Pavillion; No interpretations of USGS data yet
By Joshua Scheer, reporter, county10.com
(Riverton, Wyo.) – With about 50 people in attendance, the Pavillion Working Group was updated on a number of topics surrounding the investigation into groundwater contaminants, which could be linked to hydraulic fracturing, east of the town.
Notably, the task force testing soil in gas well pits for hydrocarbon concentrations found enough of the compound napthalene to mention it to the group. Environmental Protection Agency’s Rob Parker said the compound was the only substance found above regional screening levels. According to the federal agency’s website, the substance is used in the creation of mothballs and in the production of a chemical substitute in some plastics.
“We’ll be talking about modeling that compound,” Parker said, to see if the concentration is at levels where it could contribute to groundwater contamination and require remediation.
Oil and Gas Conservation Commission Natural Resource Analyst Tom Kropatsch said nine pits in Encana’s field were sampled.
The group talked about needing to improve data quality, as the first round of testing was unable to test for low concentrations of other compounds.
Conclusions about naphthalene and other compounds found have yet to be made.
Additionally, results from the United States Geological Survey and the EPA based on testing done at one of the EPA’s monitoring wells have been released, but interpretations of the data are forth-coming. No dates have been set for interpretation release, though Wyoming Department of Environmental Quality Director John Corra said he has urged the teams to be timely.
Much of the first three hours of Wednesday’s meeting at Central Wyoming College focused on how the USGS drew its samples and why a second monitoring well was not tested.
USGS staff explained that in order to accurately test the water in the aquifer, water in the well had to be purged to get a better sample. Samples were taken after one purge and after three purges. Debate surrounded whether or not the third was more representative of the aquifer than the first.
USGS representative Warren Day explained that monitoring well two is a low-yield well, meaning it does not produce much water. Different sampling methods were required to test it, but it was decided there was not enough time to meet the EPA’s September deadline. The EPA has since extended the deadline.
A video camera was sent into well two to determine possible causes of the low yield. Corrosion of the steel was found, as well as blockage around at least half of the screen where water enters the well. There were disagreements as to the makeup of the blockage.
The corrosion found was unexpected, USGS staff said, because the well was believed to have been construction with stainless steel. The EPA later confirmed that it was built using thread and coupled steel. The well was also found to be 9.5 feet deeper than originally thought. EPA principle investigator Dominic DiGiulio admitted schematics he had approved were incorrect and that it was good to know the wells true depth. He said the depth was not a contributor to the low yield.
-Keith Clarey of the Wyoming Water Development Office updated the working group on the cisterns project approved by the State Legislature to provide safe drinking water for residents with potentially contaminated wells. A $460,000 contract with Riverton’s James Gores and Associates is in the works for the engineering of the project. Clarey said 20 landowners have requested assistance, however three are outside of the project’s boundary. Those wells will need to be tested before being approved for aid. Gov. Matt Mead’s natural resource policy advisor Jeremiah Rieman said the project was initiated because Mead wanted to assure residents had a clean water source, and that it was not an admission of liability.
-More than an hour of discussion surrounded investigations into wellbore integrity of gas wells on Encana’s fields near the affected landowners. More data collection is needed to be sure cement in the holes are holding. There is not concern about the integrity of the wells’ casings. A separate task force meeting on the topic will be held in the near future at the Oil and Gas Conservation Commission’s office in Casper.
-No future working group meetings were scheduled.