Five natural-gas sites in Fort Worth, Texas, last year produced air pollution that exceeded state regulations, according to a study on the effects of drilling and production in the city.
Eastern Research Group Inc., a consultant hired by the Fort Worth City Council, also found visible emissions at 296 of 388 gas well sites it examined. The study was posted on the city’s website today.
The city requested the study in response to resident concerns that gas drilling, fracturing, compression and collection in the area’s Barnett Shale gas field may have an adverse effect on air quality.
The study may have implications in other onshore fields, such as the Marcellus Shale in Pennsylvania and New York, the Haynesville Shale in Louisiana and the Fayetteville Shale in Arkansas, Jason Lamers, a city spokesman, said in an interview. It’s the first study to test for emissions during all phases of gas development, including drilling, hydraulic fracturing, well completion, pipeline operations and compression, Lamers said.
“I’m very optimistic that the results of this study will advance the knowledge base, not just for the Barnett but for all of the U.S.,” Ramon Alvarez, a scientist in Austin with the Texas office of the advocacy group the Environmental Defense Fund, said in an interview.
Drilling Fort Worth
Exploration companies including Devon Energy Corp., Chesapeake Energy Corp. and Exxon Mobil Corp. have drilled more than 1,200 producing wells in Fort Worth, which sits atop about 6 percent of the 5,000-square mile (13,000 square kilometer) Barnett Shale field, Lamers said.
Eastern Research, based in Lexington, Massachusetts, used infrared cameras that can detect air pollution to inspect sites. The company took air samples at sites where it found emissions and tested the samples for pollutants. The company also built computer models showing the dispersal patterns of the emissions and calculated the emissions from compressor sites.
Most of the emissions were found to be gas; the tests also found volatile organic compounds such as benzene, along with carbon monoxide and formaldehyde, according to the study. In most cases, the pollutants dispersed quickly and posed no health risk for surrounding residents, the study said. The pollutants can contribute to the formation of ozone, which is the main ingredient in smog, Michael Gange, assistant director of transportation and public works for the city, said in an interview.
The Texas Commission on Environmental Quality is considering tighter regulations on the release of volatile organic compounds from tanks and other equipment associated with oil and gas production.
“Though the most toxic pollutants these sources emit are released in relatively low quantities, all reasonable precautions to reduce emissions from the well pads and compressor stations should be made,” according to the study.
Eastern Research recommended installing vapor recovery equipment to capture emissions from storage tanks at well sites and using electric motors on compressor stations.
Many companies are already using those techniques, said Ed Ireland, executive director of the Barnett Shale Energy Education Council, an industry group.
“Those are pretty much best management practices in the industry,” Ireland said.