Colorado oil/natural gas producers found a lot to like in a new West Slope air quality study released on Tuesday by researchers at Colorado State University (CSU). It follows bullish new reserve estimates for the Piceance Basin (see Shale Daily, June 8).
While state public health officials still have to scientifically interpret the data, the three-year CSU study of air toxics, ozone and greenhouse gas (GHG) emissions from natural gas production activity did not reveal any immediate risks to human health or the environment from gas exploration and production (E&P) operations.
However, Dan Haley, CEO of the Colorado Oil and Gas Association (COGA), cautioned that making any health risk interpretations from the CSU data "is very premature." The release of the study data is only the "first step in a scientific process as the Colorado Department of Public Health and Environment (CDPHE) will be conducting a robust health impact analysis using the data from the study," he said.
According to the study's design, however, researchers were to inform both regulators and gas operators if they identified "any measurements that appeared to be an immediate risk," Haley said.
Jeffrey Collett, professor and head of CSU's atmospheric science department and the study's principal investigator, told the Garfield County Board of Commissioners on Tuesday that researchers collected air samples from three activities during new well development: drilling, hydraulic fracturing (fracking) and flowback. They quantified air emission rates and dispersion of air toxics, ozone precursors and GHG during each of the three processes.
On a preliminary basis, drilling and fracking appear to have relatively less impact than the flowback operations in gas drilling.
A similar study has been commissioned by the state to cover the northern Front Range. Garfield County contributed $1 million toward the West Slope data gathering. The county commissioned the study, dubbed "Characterizing Air Emissions from Natural Gas Drilling and Well Completion Operations in Garfield County," in 2012, and the county environmental health officials said they are looking forward to seeing how the data set can be used in other applications."
"We have documented the types of chemicals and the amounts of those chemicals that are emitted when new wells are prepared," Collett said. "The focus was on volatile organic compounds (VOC) that are the concern as air toxics and as precursors to ozone formation and on methane, a potent GHG."
The researchers labeled as notable the fact that they observed higher rates of VOC emissions and methane during flowback operations than during drilling or fracking processes. "Flowback is the last in the chain of well completion [steps], and involves water and fracking fluids flowing up from the ground after injection of water and chemicals into the well," the researchers said.
"Methane was the most abundant compound in measured emissions, with median emissions of 2.0, 2.8 and 40 grams/second for drilling, fracking and flowback, respectively," they said.
CDPHE head for environmental epidemiology, occupational health and toxicology, Mike Van Dyke, said the CSU data should improve the public health professionals' understanding of potential health risks directly attributable to air emissions from oil/gas activities.
Haley called the study's collected data "a great first step," particularly given the announcement earlier this month regarding proven gas reserves in the Piceance (1.6 Tcf, becoming the second-largest assessment of potential continuous gas resources ever conducted by the U.S. Geological Survey) and the prospect for becoming one of the major supply basins for the proposed Jordan Cove liquefied natural gas terminal along Oregon's south-central coast, and a 238-mile connecting transmission pipeline.