Water Contamination Concerns Raised In Pavillion

Pavillion-area residents who are facing long term impacts to their property and water wells from nearby oil and gas development recently raised ongoing questions and concerns with state and federal agencies. In letters sent to the Wyoming Oil and Gas Commission (WOGCC) and the U.S. Bureau of Land Management (BLM), Powder River Basin Resource Council and affiliate Pavillion Area Concerned Citizens raised questions about Encana’s well plugging and abandonment operations currently underway.

Plugged wells have corrosion issues

A number of the wells being plugged have highly corroded casing and high gas pressures (reportedly 1000psi).   Landowner, John Fenton, provided photos of corroded casing. Now landowners are raising questions about whether the high gas pressure and degraded condition of the production well has caused unwanted migration of methane gas into the aquifer used by residents. Landowners are also asking how widespread this problem is throughout the Pavillion gas field. Representatives from the WOGCC and the BLM notified the organizations that they are looking into the questions and will respond.

Impacted resident John Fenton said, “The surface casing I witnessed that was removed from a wellhead on our property was completely rusted through. The BLM inspector present during the plug and abandonment operations did not even document this very important information in his report.”

Fenton also noted, “Is it any wonder that those of us who live near this development have lost faith in the regulatory agencies that seem to be assisting Encana and other operators in a cover up of what has happened in the Pavillion gas field.”

Expert opinion on possible water contamination

According to consulting hydro-geologist, Mike Wireman, “Natural gas can occur under high hydraulic pressure in the subsurface. This is due to the, often very thick, sequence of rocks that overlie the gas deposits. Gas that occurs in deposits under high pressure will move readily along any available subsurface pathway. Degraded casing or annulus cement in gas exploration and production wells provide such pathways. Gas under high pressure will move readily upward along these pathways and can then move horizontally into shallow aquifers used for stock and domestic purposes.”

Water contamination remains a concern

These new developments came to light in September during recent plugging activities by Encana in the Pavillion field.  The ongoing investigation by the state into contamination from unlined production pits, inadequate production well construction and high subsurface gas pressures as well as the ongoing Wyoming Department of Environmental Quality investigation of contamination in domestic water wells continue to point to serious and widespread soil and groundwater contamination problems in the field.

Residents are very concerned that drinking water wells have been contaminated. The purported contamination is likely due to casing failures and subsequent gas migration into drinking water aquifers, and leaking unlined pits. These issues continue to be a significant problem and demonstrate the need to hold Encana and other historic operators liable for mitigating the environmental damage and providing water replacement for impacted households.

To learn more about this ongoing story, follow Powder River Basin Resource Council on Facebook. You can also read a recent article about Pavillion featured on Wyoming Public Radio.

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