SYCAMORE, Pa. — The towering flares that turn night into day in the Marcellus Shale gaslands are becoming an increasingly rare sight.
Natural-gas producers are turning to new techniques to capture the gas emitted during the well-completion process. In the past, a well’s initial production was typically vented or burned off to allow impurities to clear before the well was tied into a pipeline.
Now, more operators are employing reduced-emission completions - a “green completion” - using a process in which impurities such as sand, drilling debris and fluids from hydraulic fracturing are filtered out and the gas is sold, not wasted.
Five gas wells that EQT Corp. completed in October at a remote site in Washington Township, are typical. Compared with a gas flare, which roars like a jet engine and lights the sky with flames, green completion is dull and quiet.
EQT is not the only drilling company embracing green completions. Equipment for separating the gas from the “flowback” has been perfected over the past decade and will become standard practice across the nation over the next three years.
The federal Environmental Protection Agency approved new rules this year requiring green completions nationwide by 2015, except for exploratory wells unconnected to pipelines. As of Oct. 15, drillers could no longer vent the gas into the atmosphere without burning.
The EPA says green completions will save drillers up to $19 million a year by capturing natural gas that would be wasted.
The advent of green completions is an example of the rapid development of shale gas technology, which has revived a flagging domestic energy sector.
“What was true yesterday is no longer true today,” said Andrew Place, director of public policy research at EQT, based in Pittsburgh. “Systems are evolving.”
Much of the new technology has been driven to address fears about drilling, including hydraulic fracturing, the extraction technique that has turned impermeable shale into a bonanza of oil and gas.
“Public concerns have pushed the engineers to come up with solutions,” Place said.
In Arkansas, drillers are using similar techniques to reduce emissions.
Christina Fowler, spokesman for Houston-based Southwestern Co., which is one of the largest natural-gas drillers in Arkansas, said in an e-mail Friday that the oil and-gas producer uses "green completions" to complete all of the company’s wells in the Fayetteville Shale.
“After the hydraulic fracturing process has been finished, we capture all of the natural gas brought to the surface in a closed-loop system,” she wrote. “The natural gas that flows back is re-injected into the well to aid in equalizing the pressure until the well is put online.”
Fowler said that before natural gas from one of its wells goes through a transmission line, it goes through a separator where water that “flows back” is removed and put in storage tanks. The water is then used during the fracking of another well or sent to a disposal well.
Activists and regulators are paying more attention to air emissions from shale-gas development, including toxins emitted during drilling and production. Much of the focus has been on releases of methane, which is the main component of natural gas as well as a potent greenhouse gas, though there is substantial disagreement over studies attempting to measure the methane leaks.
In devising the new rules, the EPA said it was acting under its Clean Air Act mandate to reduce emissions of volatile organic compounds and pollutants such as benzene, which can cause cancer. The agency said the new rules were expected to eliminate 95 percent of the smog-forming volatile organic compounds emitted from more than 13,000 new gas wells each year.
The EPA said a “co-benefit” of green completions was a reduction in methane emissions by 1 million to 1.7 million tons a year.
At EQT’s drilling site on Pettit Run Road in rolling farmland about seven miles northwest of Waynesburg, workers use a kind of assembly line drilling operation that incorporates green completions.
Before EQT began drilling, the company first extended its pipeline network to the location so it would be ready to receive any gas produced, said Michael Rehl, manager of completion operations.
The company drilled five wells in a row, spaced 15 feet apart, to a depth of about 7,500 feet, where they turn horizontally into the Marcellus Shale layer and follow parallel paths, separated by about 1,000 feet. The wells were then lined with several layers of steel pipe and concrete and hydraulically fractured.
The completion process commenced when a contractor, Pure Energy Services Ltd ., began cleaning out wells one at a time, collecting the sand, water and chemicals used during the fracking process, which are initially disgorged by the well.
During a green completion, the mixture is routed through a series of filters. A cylindrical sand trap collects the solid materials, which are sent to a landfill. The water, containing the chemicals and mineral contaminants, is treated and stored for reuse in the next drilling operation.
Although the government delayed full implementation of the new rules until 2015 to allow the industry to build enough equipment to handle the workload, the American Petroleum Institute and other industry groups are challenging them in court. So are environmental groups.
“We’d say the rules have not gone far enough,” said Jay Duffy, a staff attorney with Philadelphia’s Clean Air Council, which joined with Earth justice in October to notify the EPA it planned to sue.
Anti-drilling activists argue that so much methane escapes from gas development it undermines the industry’s claims about the clean-air benefits of the shale-gas boom.
The industry says environmentalists and the EPA are using inflated, biased estimates of methane emissions. It has denounced as hoaxes some of the infrared videos posted online that purport to show methane plumes.
Some industry leaders say green-completion technology could put the emissions debate to rest.
“I do think it addresses a criticism that the industry has had in terms of methane emissions, and maybe we can take that off the table,” Jack P. Williams Jr., president of XTO Energy, said in a recent interview.
Information for this report was contributed by Jessica Seaman of the Arkansas Democrat-Gazette.
Business, Pages 21 on 12/03/2012