Abandoned wells could have major consequences
It came as news to Jeff Parsek that state records show there is an abandoned oil and gas well beneath his driveway. He lives in a large ranch house right across the street from an elementary school, in a subdivision on the south side of Fort Collins. It’s a nice neighborhood, with the new feeling of many Colorado suburbs.
When he bought the house in 2004, he didn’t ask about oil and gas wells on the property.
“I wouldn’t have even thought to research that,” he said. But the news that there might be one under his driveway also didn’t faze him. While other homeowners responded to the search for potentially lost wells with curses and slammed doors — one yelled “Thanks for ruining my afternoon!” — Parsek just shrugged.
“If it started to emit something, then I might (be worried),” he said. “But to this point, I’m not concerned.”
The question is whether one would know an abandoned well is emitting. When a well stops producing commercial quantities of oil and gas, companies “abandon” it by placing cement plugs inside the wellbore to stop the flow of gas and fluids. The industry considers that the end of the life of a well.
“It’s not rocket science to plug these wells,” said Wyoming Oil and Gas supervisor Mark Watson. “It’s a hole in the ground that’s pretty deep. You set cement, and cement lasts a long time.”
That conventional wisdom, that a well is dead once it is plugged with cement, means there’s no systematic monitoring of any of the millions of abandoned wells in the United States. In Colorado alone, there are more than 35,000 abandoned wells. There are more than 50,000 in Wyoming.
“When a state sees a well is plugged, they typically put a checkmark by that well in a database or in a file somewhere, and they don’t do anything (else) for the most part,” said Rob Jackson, a scientist at Stanford University in California.
So unless a well starts leaking fluids or a house blows up, the assumption is that everything is fine.
But recent work by Jackson’s research group challenges that idea.
Methane is the main component of natural gas, and it is present in every oil and gas well. It is also a potent greenhouse gas and potentially explosive if it accumulates in confined spaces.
In Pennsylvania and California, he and his colleagues have tested abandoned wells, both plugged and unplugged, for methane leaks. The results were surprising. In most cases, the wells were leaking extremely small quantities of methane, but a few wells were leaking a lot — orders of magnitude more. And it wasn’t just the unplugged wells. Some of those “super-emitters” had been plugged.
In Pennsylvania, one of his colleagues, engineer Mary Kang, estimated that abandoned wells account for 4 to 7 percent of the state’s total man-made methane emissions.
The province of Alberta, the energy center of Canada, requires companies to monitor some abandoned wells. They’ve found that, on average, 7.7 percent of wells end up leaking.
But whether those results translate to Colorado and Wyoming is hard to say since no one is looking for leaks. Jackson thinks that is partly an issue of states not having the resources to monitor.
“But I also think the states aren’t that interested in some cases, in many cases, in the data. I’m not sure they really want to know,” he said.
Even if they did, it is not clear they could actually find the wells.
Once a well is plugged with cement, it is cut off below-ground, covered up with dirt and then, more often than not, never thought of again. Sometimes, a dead well is marked with a tombstone of sorts, a marker listing its unique identifying number. But often there’s no indication at all on the surface that there was once a hole many thousands of feet deep, tapping reservoirs of gas or oil.
Inside Energy discovered as much on a recent afternoon when searching for abandoned oil and gas wells around Fort Collins. Despite having coordinates downloaded from the state oil and gas database and multiple GPS devices, actually finding the wells proved complicated. At one site, the supposed GPS coordinates of the well were directly underneath a giant tree.
At other sites, the wells were supposedly under roads or driveways or houses. None of them were marked, so it’s possible the wells were there, or it’s possible they were somewhere else entirely.
A few years back, Robert Kirkwood, a researcher with the Wyoming Geological Survey, was tasked with locating several hundred active and abandoned oil and gas wells in southwestern Wyoming. He found that a quarter of them weren’t where they were supposed to be. Some of them weren’t even close. The furthest well was more than a mile away from where records indicated it was supposed to be.
“Some of those were just found fortuitously because we were just walking and walking and then I could see the marker through the sagebrush, and I would be like ‘There’s something over there!’ Walk over to it. There it is,” he said.
Others, without markers, he never found. Out in the middle of the Wyoming desert, a few lost wells might not be a big deal, but, in other areas, like the Front Range of Colorado, where houses and schools and shopping centers are encroaching on old oil fields, it might pose a bigger problem.
“From a public safety-perspective, even a slow leak into a building can create an accumulation in the building and then cause an explosion hazard,” said Theresa Watson, an engineering consultant and former energy regulator in the Canadian province of Alberta.
She is quick to point out that there is a very, very small risk of an abandoned well causing an explosion, but it does happen. If a well isn’t properly sealed, methane gas can travel up and accumulate in confined spaces, like a basement. Houses built on old wells have exploded as recently as 2007 in Trinidad, Colorado and 2011 in Bradford, Pa.
“I wouldn’t move because of it, I don’t think,” she said. “But what I would do is I would probably put a methane monitor in my house.”
Which brings us back to Parsek. Fort Collins city officials acknowledge that they don’t actually know where the well that’s supposedly under his driveway is. It could be where the database shows it is, or it could be under his house — or even beneath the elementary school across the street. The well was drilled and abandoned in 1982. But it wasn’t until 2005 that Colorado started requiring precise GPS locations for active wells.
One way to prevent that kind of uncertainty is to make developers locate wells before anything gets built, which is what Watson recommended for Alberta, when she was a regulator there.
“The municipalities have a requirement now to make sure that developers look for them and confirm that there aren’t any in the way of their development, or if there are, how they’re going to maintain the setback required,” she said.
The setback is a 15-foot no-build zone around abandoned wells. Similar rules are lacking in much of the U.S., even as development continues to encroach on old oil fields. Watson, Wyoming’s oil and gas supervisor, has fielded calls this year from landowners in the city of Gillette and even from the Campbell County government about building on top of abandoned wells.
“We suggested to them, ‘Hey, it’s probably not a good idea to put your building on top of an abandoned well,’” he said.
But neither Gillette nor Campbell County has any prohibition on it, so ultimately the judgment call lies with the landowner or developer. The same is true for most municipalities in the region. The city and county of Broomfield is one Colorado exception.
“We would require that the developer or the property owner dedicate an easement over the well site, the former well site,” said Anna Bertanzetti, Broomfield’s principal planner. “It has to be at least 50 feet wide by 100 feet long and have access to public roadway.”
The idea is to leave room, so that if the well ever leaks and needs to be fixed, a rig can access it. In addition to the dedicated easement, Broomfield requires property owners within 200 feet of the well be notified. With local governments in the region paying so much attention to new oil and gas development, she said, it’s common sense to look at the old, too.
“I think it’s appropriate,” she said.
And some other locales are adopting rules. In 2013, Fort Collins embraced regulations requiring a 350-foot buffer between new housing development and old wells. Longmont and Weld County also have buffers of 150 feet and 25 feet, respectively. But none of the rules address development that’s already happened on top of abandoned wells, and the patchwork of regulations can mean neighbors are governed by different standards.
One site visited on the search for abandoned wells was just outside Fort Collins city limits, in Larimer County — and therefore just outside the reach of the new buffering regulations. The site was unmarked, but, to the trained eye, it was clearly an old well pad — big flat area, discernable berms and an access road.
If someone didn’t know to ask about abandoned wells, they might find it an enticing spot to build a home. And as ill-advised as it may be, in many parts of Colorado and Wyoming, there would be nothing stopping them from doing just that.
Stephanie Joyce reports on energy and natural resources for Wyoming Public Radio; firstname.lastname@example.org. Jordan Wirfs-Brock is a data journalist for Inside Energy and civic technologist whose passion is telling stories with data and empowering others to do the same; email@example.com.
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