June 15, 2016

New Study Of Air Toxics At Colorado Oil And Gas Sites

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Researchers from Colorado State University presented results of a three-year, $2 million study measuring oil and gas emissions in Garfield County on Tuesday. Garfield County sits atop the Piceance Basin, home to the second-largest natural gas reserve in the country. The study provides new data on a type of air toxics known as volatile organic compounds, or VOCs. These chemicals contribute to the formation of harmful ground-level ozone and can have negative health impacts even at low concentrations.

At a Garfield County Board of Commissioners meeting, lead researcher Jeff Collett of CSU emphasized four ways the study is unique:

  1. Partnership between researchers, local government and industry;
  2. Detailed measurements of VOCs in addition to methane, the more studied chemical emitted from oil and gas operations;
  3. Data collection at multiple points in the life cycle of a well, including new drilling sites;
  4. Focus on emissions rates — the amount released each second — as opposed to point-in-time snapshots of chemical concentrations.

Collett and his team measured emissions of 48 different VOCs, as well as methane, at 21 separate oil and gas sites in Garfield County between 2013 and 2015.

Garfield County requested and funded the study, along with six oil and gas companies: Encana Corporation, WPX Energy, Bill Barrett Corporation, Ursa Resources Group, Caerus Oil and Gas, Laramie Energy.

Although some may raise an eyebrow at industry involvement, Collett said it was key for getting accurate data: “The involvement of industry, which is not always typical of other studies, allowed us full access to the sites,” said Collett at the public meeting. “That was critical to how we made the emissions measurements.”


Image from Jeff Collett's presentation to Garfield County

This image, from Jeff Collett’s presentation to Garfield County, shows how the data collection process works. A known quantify of a gas, acetylene, is released at a well site. Stationary and mobile instruments downwind measure that reference gas, called a tracer, along with other gases emitted from the well site to determine how they are dispersed over time and space.

The study looked at the development of new wells, including preparation of the well pad, drilling, fracking, flowback and well completion. Emissions levels were highest during the flowback stage, when fluids injected into the ground during the fracking process are brought back up to the surface and removed.

Dan Zimmerle, an air quality scientist at CSU not involved in the study, commented on the various stages of the drilling process the study examined: “Each one of those has a different impact on the surrounding community. So it’s good to have a study of the entire lifecycle to understand what impacts occur at what time.”

Full analysis of the data, including a health risk assessment by the Colorado Department of Public Health and Environment, is planned for the future. Comprehensive data from the CSU study will be released to the public on July 1.

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