Posted on Thu, Feb. 12, 2009
Barnett Shale drilling causes nearly as much air pollution as vehicles in the Metroplex, a study says
By MIKE LEE
mikelee@star-telegram.com
Air pollution from natural gas drilling in the Barnett Shale is a big problem but it can be easily controlled
with existing technology, researchers said this week.
The giant natural gas field, with 7,700 wells and counting, produces nearly as much air pollution as all the
cars and trucks in the Metroplex, according to a study by Al Armendariz of Southern Methodist University and
Ramon Alvarez of the Environmental Defense Fund. And unlike most oil and gas production, it’s centered on a
highly populated area.
"We have to come up with viable solutions," Alvarez said.
"The good news is that there are a lot of viable technologies to reduce the emissions."
Gas drilling creates several kinds of pollution.
Carbon dioxide and soot are created by the engines used to power pipeline compressors.
Methane, the primary ingredient in natural gas, is a powerful greenhouse gas. It can escape from leaky pipes and equipment,
and it is also sometimes vented into the air when wells are being completed.
Volatile organic chemicals, including hazardous chemicals such as benzene and formaldehyde, are released from leaky tank
batteries, where crude oil is separated from natural gas.
The year-round average for all types of drilling-related pollution is 191 tons per day. In the summer, when North Texas’
air pollution is at its greatest, the emissions can rise to 307 tons per day because the heat causes more evaporation.
A draft of the study released in November pegged the number at 262 tons per day.
All the cars and trucks in the nine-county Dallas-Fort Worth area produce 273 tons per day, according to the Texas
Commission on Environmental Quality.
Fort Worth recently adopted an ordinance that requires companies inside the city to use "green completion" technology,
which removes sand and debris from wells without releasing methane. The city is working with state legislators on a
bill that would require the same methods throughout the Barnett Shale field.
At least one energy company, Devon, began using green completions routinely because doing so helps the company pump
more gas from its wells.
The technique could also be useful if the federal government starts regulating greenhouse gases, which many
environmentalists predict is possible, Alvarez said.
Using electric motors for compressor stations would also reduce emissions, the report says.
Green completions require access to a pipeline, and electric motors require a stable source of power.
But Alvarez said, "Those are logistical problems," which are more easily solved since the Barnett Shale is
in a well-developed area.
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