DEP study of leaky abandoned wells tries to quantify a hidden climate threat

Pittsburgh Post-Gazette

By Laura Legere

May 24, 2016

RUSH TOWNSHIP, CENTRE COUNTY — The rusty gas well in the forest clearing was easy to spot, its vent pipe as tall as a man and the grass around it only shin high.

For the novice well hunters who traveled to the tract of state game lands last week, the 33-year-old well was a suitable substitute for less conspicuous relics of older oil and gas extraction eras they were learning how to identify.

The idea is to take stock of an unwieldy class of hundreds of thousands of abandoned wells in Pennsylvania about which little is known, including where exactly they all are.

Researchers with the state and at various universities and institutions are trying to determine what risk the old wells pose to the climate, the surrounding soil and water, and human health.

The most acute risks are well known — abandoned wells have channeled gas into homes, creating the conditions for explosions.

The scale of the wells’ less visible hazards is still emerging. A 2014 study by Princeton University researchers of 19 old plugged or abandoned wells in Pennsylvania found that all of them were emitting methane and some were spewing significant amounts of the potent greenhouse gas.

The historical wells are not counted in official greenhouse gas emissions inventories, but taken together the state’s estimated 300,000 to 500,000 abandoned oil and gas wells could be releasing as much as 4 percent to 7 percent of the total human-caused methane emissions in Pennsylvania, the study suggested.

Now, a group within the Pennsylvania Department of Environmental Protection is embarking on a study of 208 wells that were abandoned before modern oil and gas plugging requirements were established in the state in 1984.

The DEP study’s leaders hope both to calculate the total potential methane emissions from the state’s abandoned wells and to identify emissions trends. Perhaps wells from certain eras, regions or depths, or those that used particular materials or plugging techniques, will emerge as high emitters that should be addressed first.

“Getting these numbers is important because it tells people at the federal level and the state level where to put their money,” said John Bradshaw, a physicist at Indiana University of Pennsylvania, who is conducting a separate study of how much abandoned gas wells in Western Pennsylvania contribute to total emissions of stray methane.

Methane is more effective at trapping heat but it leaves the atmosphere more quickly than carbon dioxide, so eliminating methane leaks — from legacy wells, new natural gas infrastructure and agriculture — is a strategic step in addressing climate change, he said.

There is little money at DEP’s disposal for plugging even the known abandoned wells on its list. Stewart Beattie, a DEP information specialist, estimated there will be enough funding to plug fewer than 10 wells this year.

A separate account, funded by impact fees on new shale wells, is available to provide grants to organizations, businesses or communities for well plugging. Few groups have applied for the funding. DEP is urging more communities to take advantage of it.

Mary Kang, who led the Princeton study as a doctoral candidate and is now a postdoctoral fellow at Stanford University, said she has done follow-up research to characterize methane emissions from abandoned wells, but more data collection from DEP and others is necessary.

“The sampling approach needs to be strategic,” she said in an email, “especially because it is not realistic to measure all abandoned wells.”

DEP picked 208 wells as a representative sample of the known plugged and abandoned wells in the state’s databases. They include oil and gas wells, wells that tapped both types of fossil fuels and wells of unknown type. The sample wells are scattered across eight Western Pennsylvania counties — Allegheny, Washington, Greene, Armstrong, Indiana, Venango, Warren and McKean.

Field work is expected to finish in the fall. DEP plans to release its findings sometime afterward.

So far, the team has evaluated wells in Indiana and Venango counties, DEP geologic specialist Lindsay Byron told a state climate change advisory board last week.

Three of the wells the team inspected in Indiana County were leaking detectable amounts of methane and two of those had measurable flow rates, with one plugged well releasing 1.8 cubic feet of gas per day and one abandoned well releasing 1,400 cubic feet of gas per day.

They also found one orphan well discharging water to a wetland at a rate of about 4 gallons per minute, but without causing any apparent impacts to the vegetation, Ms. Byron said.

Of the seven wells in Venango County that the team has inspected so far, none was discharging any gas, oil or brine.

The sample wells in DEP’s study are also representative in that some are difficult or impossible to find.

The team members could not locate two of 12 wells they were looking for in Indiana County, likely because the wells were plugged and their tops were buried below ground. And the team members found, but couldn’t definitively identify, three of the seven wells they inspected in Venango County.

“Which means three of them, when we got to the location, there was no casing present and it was just a hole in ground,” Ms. Byron said. “Which is pretty typical of that area.”

‘Trying to make some kind of dent’

DEP’s official tally of orphaned and abandoned wells includes fewer than 14,000 sites, and its records include tens of thousands more wells whose locations are vaguely known but exact coordinates are missing.

That still leaves potentially hundreds of thousands of legacy wells that have yet to be found.

Which is where the well seekers on the state game lands come in.

Penn State researchers are working to track down the wells by training volunteer citizen-scientists to find clues everywhere from historical map archives to public forests. The initiative, supported by a National Science Foundation grant, engages community members in finding and mapping wells, which are then reported to DEP for evaluation.

“We’re trying to make some kind of dent in this important problem,” said Nooreen Meghani, a research assistant in Penn State’s Earth and Environmental Systems Institute, who is leading the project.

Before heading out to find the well, the group looked at the flow of gas from an unlit blow torch through a special infrared camera — a high-tech tool for visualizing gas leaks invisible to the naked eye.

In the field, DEP mineral resource program specialist Rick Swank assured the group you don’t necessarily need fancy equipment to tell if a well is leaking gas.

“One of the simplest things that you can carry with you to see if there are any methane emissions is actually a bottle of soap solution,” he said. “A lot of the industry uses Dawn or Mr. Bubble.” The soap, sprayed on well fittings or the soil around the well, will bubble if gas is seeping out.

With severe leaks, a gas well might be visibly or audibly venting. In which case, he said, “Don’t even go near it. It’s not worth the squeeze.”

Laura Legere: llegere@post-gazette.com.


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