Fracturing Flashpoint: Pavillion, Wyoming

Although fracturing shale to access and produce natural gas has vastly increased the U.S. supply, the potential of the chemicals used in the fracturing process to contaminate drinking water sources remains a concern for many.  While the proximity of fracturing activities to drinking water supplies varies from field to field, the area near Pavillion, Wyoming has become a focal point for the groundwater contamination issue.  In response to complaints by landowners regarding objectionable taste and odor problems in well water, the U.S. Environmental Protection Agency initiated a ground water investigation near Pavillion, installing two deep monitoring wells in June 2010.  The objective of EPA's investigation was to determine the presence, not extent, of ground water contamination and, if possible, to differentiate shallow source terms (pits, septic systems, agricultural and domestic practices) from deeper source terms (gas production wells).  A draft report issued in December 2011 stated that "the data indicates likely impact to ground water that can be explained by hydraulic fracturing."

Encana, a major gas producer, strongly disagrees with the EPA's draft report.  According to Encana:

"Numerous discrepancies exist in the EPA's approach, data and analysis. A few of these discrepancies are:

  • The EPA report ignores well-known historical realities with respect to the Pavillion field's unique geology and hydrology.
  • The EPA drilled two deep monitoring wells (depth range: 783 — 981 feet) into a natural gas reservoir and found components of natural gas, which is an entirely expected result. The results in the EPA deep wells are radically different than those in the domestic water wells (typically less than 300 feet deep), thereby showing no connection. Natural gas developers didn't put the natural gas at the bottom of the EPA's deep monitoring wells, nature did.
  • There is unacceptable inconsistency between EPA labs' analysis for numerous organic compounds reported to have been found in the EPA deep monitoring wells. Data is not repeatable and the sample sets used to develop these preliminary opinions are inadequate.
  • Several of the man-made chemicals detected in the EPA deep wells have never been detected in any of the other wells sampled. They were, however, detected in many of the quality control (blank) samples — which are ultra purified water samples commonly used in testing to ensure no contamination from field sampling procedures. These two observations suggest a more likely connection to what it found is due to the problems associated with EPA methodology in the drilling and sampling of these two wells.
  • The EPA's reported results of all four phases of its domestic water well tests do not exceed federal or state drinking water quality standards for any constituent related to oil and gas development."

New USGS Data Released

In April and May 2012, the U.S. Geological Survey collected groundwater-quality data and quality-control data from one of the EPA's two monitoring wells.  Two groundwater-quality samples were analyzed for field water-quality properties (water temperature, pH, specific conductance, dissolved oxygen, oxidation potential); inorganic constituents including naturally occurring radioactive compounds; organic constituents; dissolved gasses; stable isotopes of methane, water, and dissolved inorganic carbon; and environmental tracers. Quality-control sample results were evaluated to determine the extent to which environmental sample analytical results were affected by bias and to evaluate the variability inherent to sample collection and laboratory analyses.

The data from USGS has not caused EPA or Encana to change its position.  EPA spokeswoman Alisha Johnson said that the new USGS data "is generally consistent with groundwater monitoring data previously released by the Environmental Protection Agency."  But noting that USGS' data came from just one of the two monitoring wells because the other well had insufficient water flow, Encana remains steadfast that EPA's wells are improperly constructed, and is unsurprised by the USGS data.

In response to the new USGS report, Wyoming Governor Matt Mead said, "I feel that the process used to acquire this data was an improvement on the process used for the draft EPA report last December. ... We are now waiting as analysis of this data is done.  It should help inform the peer review process."

The final EPA report on the water study is expected some time next year, but the debate is sure to continue in Wyoming and elsewhere.

No comments yet

Start the discussion by using the form below

Post a comment

Fill out this form to add a comment to the discussion
I'd like to leave a comment. is