Wastewater disposal remains a point of debate in gas drilling
08/01/2010 11:18 PM
08/02/2010 6:38 AM
Four years after Fort Worth banned disposal of wastewater from natural gas drilling in the city limits, the rhetoric has cooled, but there's no end in sight to the debate over safety and cost.
Energy companies once said they couldn't drill for gas in the city if they weren't allowed to drill disposal wells. One company even threatened to sue.
About 1,200 gas wells later, the City Council last month extended the ban until 2011. Some members remain wary of allowing the injection wells, saying that salty, oily waste could leak into the groundwater.
The gas industry generally wants the city to allow more injection wells, and it says leaks are rare in Texas, which has 12,000 disposal wells.
Chesapeake Energy, which has the only disposal well inside the city limits, is in the early phases of a pilot project to test whether the wastewater can be partially recycled.
Disposing of wastewater is one of the biggest headaches that the natural gas industry faces. It takes 3 million to 5 million gallons to hydraulically fracture each well in the Barnett Shale, the gas-laden rock formation beneath Fort Worth. Most of that water flows back to the surface, and when it does, it can contain drilling chemicals, crude oil and more salt than seawater.
The bigger problem, according to the industry, is the naturally occurring water that is trapped in the shale along with the natural gas. This "produced water" can be three times as salty as seawater and can contain metals, chemicals and traces of crude oil.
Each gas well can create hundreds of barrels of produced water a day -- for years -- and there are already 1,200 wells inside the city, so the disposal problem is huge.
So far, all the disposal options have had drawbacks.
Fort Worth used to allow operators to dispose of less-troublesome flow-back water in the city sewer system, but only in limited cases. The city charged the operators a fee based on the volume of wastewater and an additional fee for the amount of "dissolved solids" the waste contained.
The industry decided that removing dissolved solids isn't worth the cost, said Jerry Pressley, a superintendent at the Village Creek Wastewater Plant.
Some companies use portable distillation plants to recycle their flow-back water, but the process hasn't been used on the more-difficult produced water. Some researchers have suggested using reverse-osmosis filters, but the technology hasn't been employed on a large scale.
The oil and gas industry has traditionally used deep injection wells to dispose of produced water. Fort Worth didn't allow injection wells from 2001 to 2006 because of the potential for leaks and spills.
"That's always going to be a concern," said Brian Boerner, the city's environmental director.
The city began allowing disposal wells under tight conditions in 2006 but imposed a moratorium after a few months. Another company got a permit for the well on East First Street shortly before the moratorium was imposed and later sold it to Chesapeake.
The ban on disposal inside the city means that waste must be trucked to wells in rural areas. That not only increases costs for the gas companies but also places a burden on the rural areas. Wise County, for instance, has 30 disposal wells, said Sharon Wilson, Texas director of the Oil and Gas Accountability Project.
"On one hand, I support Fort Worth for having a moratorium and trying to keep their water safe," Wilson said. "On the other hand, that's just kicking the can down the road to another community that's probably not as fortunate."
In 2008, Chesapeake offered a proposal: If the city would allow it to widen the use of the injection well, the company would experiment with evaporating the wastewater to reduce the volume to be disposed of. The company is trucking wastewater to the East First Street disposal well from 31 other pad sites in Fort Worth. That has already reduced the number of trucks on the road, said Brian Murnahan, a Chesapeake spokesman.
The evaporation system is still in the early phases. It uses heat from two large pipeline compressor engines at the East First Street site to heat the wastewater, causing fresh water to boil off.
It's one step short of full recycling -- the fresh water is released into the air instead of being reused -- but it does reduce the waste to be disposed of.
Currently, the system is offline while the company waits on parts, said Dave Leopold, Chesapeake's operations manager for the Barnett Shale. When it's running, it can handle 1,250 barrels a day, out of an average of 5,000 barrels that the disposal well handles each day, company officials said.
Critics say the evaporation system could release pollution, since any petroleum or chemicals would likely evaporate before the water. Boerner said it's more likely that any pollutants would "flash" out of the wastewater as it's stored in tanks at each well site.
Regardless, the city plans to test the air around the East First Street disposal well.
Chesapeake is also building pipelines to transport wastewater from pad sites to the disposal well, which the company says could help reduce truck traffic. Ultimately, Chesapeake wants to drill more disposal wells and connect them with pipes.
"Hopefully, when this pilot is done, the city is comfortable with allowing some more saltwater disposal wells," Leopold said.
Wilson said the city should tread carefully. The Oil and Gas Accountability Project recommends a series of safeguards for injection wells, including more frequent inspections and routine cleaning of pipes used to transport wastewater.
The Fort Worth City Council reapproved its moratorium on disposal wells recently, but it's clear that some members want a more permanent solution.
"I guess I need someone to tell me why we don't make this a permanent moratorium," Councilman W.B. "Zim" Zimmerman said.
Mike Lee, 817-390-7539
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