A difficult calculation
New estimate of abandoned Pa. wells less dire, still daunting
Maybe the number of old oil and gas wells lost in Pennsylvania’s landscape isn’t as enormous as the worst-case estimates suggest.
Terry Engelder, professor emeritus of geosciences at Penn State, has a new appraisal based on historical records that is, in comparison, merely overwhelming.
Mr. Engelder is famous for his estimates, most notably his calculation of the amount of recoverable natural gas trapped in the Marcellus Shale that helped trigger a world-changing rush to explore it.
In recent presentations to the state’s crude oil development council and online through the Penn State Extension, he suggested that the total number of wells ever drilled in Pennsylvania is 382,000.
Minus the state’s active wells, that would leave 252,000 plugged and abandoned wells, of which the Pennsylvania Department of Environmental Protection has no record of at least 168,000.
That big number is significantly lower than the 470,000 to 750,000 abandoned wells that a group of researchers led by Mary Kang, a postdoctoral researcher at Stanford University, said in a 2016 paper could be lingering in Pennsylvania’s forests, fields and neighborhoods.
The count matters because abandoned wells can be dangerous and contribute to climate change. Depending on its state of decay, each well is a potential conduit for gas and oil to reach the surface, which can interfere with modern drilling, pollute
streams and drinking water, create explosion hazards in homes and add the potent greenhouse gas methane to the atmosphere.
Ms. Kang said in an email that Mr. Engelder’s analysis “does not appear to be as thorough as mine and includes only select and very few documents,” some of which conflict with other historical records. She said her recent fieldbased research, which has not yet been published, provides “evidence for much higher numbers of wells” than Mr. Engelder’s estimate “and closer to my 2016 paper.”
A major difference between the two estimates is that Ms. Kang’s research indicated that past records largely left uncounted early enhanced recovery wells, which were used to send water underground to increase the flow of oil to production wells. Mr. Engelder finds evidence in the historical records that those helper wells were already counted.
The two studies also differ in the multiplier factors they use to adjust for undercounted wells.
The higher estimates in Ms. Kang’s paper have influenced the state’s perception of the scale of Pennsylvania’s abandoned well problem. DEP staff presented a research poster at a geology conference this year that figured that plugging 200,000 legacy wells would take $8.4 billion — or about 11 times the environmental agency’s entire annual budget — but if Ms. Kang’s well inventory estimates are correct, the cost of addressing every well would increase “nearly threefold.”
“Often political decisions can be swayed by numbers one way or the other,” Mr. Engelder said. “We would like to have numbers that are not exaggerated when it comes time for policy decisions to be made.”
For the DEP, which inherited the burden of dealing with more than a century’s worth of ownerless, unplugged wells, the focus is on tackling the tiny fraction of the predicament it has quantified.
“We have to keep in mind that DEP is aware of about 8,000 of these wells right now. That’s the inventory we have in our database,” Seth Pelepko, a DEP program manager, said at a recent meeting of an advisory council for conventional drillers. “Even a number like 8,000 is a big problem.”
The agency and the conventional drilling industry are trying to address the backlog differently than they have in the past.
With a small and shrinking pot of money, the DEP can afford to plug only the riskiest wells as they present public safety emergencies. But if the problem could be reframed — as an opportunity to provide work to the state’s struggling, small traditional drilling companies or by using data to illustrate the risks to individual communities and ecosystems — perhaps it would convince lawmakers to create financial incentives for plugging abandoned wells, Mr. Pelepko said.
DEP staff have conceptually grouped the 8,169 verified abandoned wells into 500 plugging projects, most of which would involve sealing several wells at once to reduce costs.
For example, plugging the 120 highest-risk wells on the DEP’s list one by one would cost about $5.7 million, Mr. Pelepko said, but 13 times as many wells could be plugged for only seven times the total cost if the priority wells were grouped with other nearby wells.
In an ideal world, the DEP would be implementing that strategy today, said Scott Perry, DEP’s deputy secretary for oil and gas. But, in reality, the agency has only about $600,000 available to plug abandoned wells.
The Commonwealth Financing Authority just awarded another $657,000 in grants from shale drillers’ impact fees for three abandoned well-plugging projects in Allegheny, Venango and Clarion counties — a modest amount for the scale of the problem, but the most the authority has directed to well plugging so far.
Three down, thousands to go.
“We have to keep in mind that DEP is aware of about 8,000 of these wells right now. ... Even a number like 8,000 is a big problem.” — Seth Pelepko, DEP program manager