Zoom in on Leetsdale on the state Department of Environmental Protection’s new map of legacy oil and gas sites in Allegheny County and you will see a cluster of yellow diamonds, representing long-forgotten oil wells, under what is now an industrial park on the eastern bank of the Ohio River.
These wells are not in any official state database and their locations have not been verified in the field. They were plotted from paper mine maps drawn in the 1930s and they offer a best guess for the thicket of hazards left over from earlier eras of drilling that have been paved over, in some cases literally, on the outskirts of the modern city.
“If I lived in the suburbs, I would be very interested to know what might be in my backyard,” said Stewart Beattie, a DEP information specialist, who created the map.
DEP this week released a host of information about Pennsylvania’s abandoned oil and gas wells, including the results of a year-long study that helped clarify how hard the wells are to find based on old records in a changing landscape; how often they might be leaking; and how much it might cost to plug them to modern standards.
Estimates put the number of unaccounted for wells in the state somewhere between 100,000 to 560,000. DEP predicts it would cost as much as $8 billion to plug 200,000 of them.
Since the 1980s, DEP has plugged 3,066 legacy wells that don’t have current owners. But what the agency calls “gross underfunding” of its well plugging program has caused a steady decline in the number of wells decommissioned during the past decade — from a peak of about 350 wells in 2007 to 2016, when no routine plugging contracts were issued.
The wells are remnants of a century of oil and gas drilling before wells needed to be registered or permitted. They were often left unplugged or stoppered with items like pieces of wood.
Solutions to the state’s legacy well problem “will not be possible without finding new sources of revenue for the plugging program,” which now relies almost exclusively on surcharges attached to drilling permits, the study says.
At current funding levels, or even with an additional $2.5 million a year, the state’s inventory of roughly 10,000 confirmed orphaned and abandoned wells will grow by thousands over the next 100 years as newly discovered legacy wells are added to the list, according to DEP’s new forecast. With an additional $15 million in funding per year, the backlog of wells in DEP’s databases could be eliminated in 40 years.
After money, a second hurdle to plugging the wells is finding them.
DEP set out to study 207 wells in Western Pennsylvania that are representative of the thousands in its databases, but researchers could find only 136 of them in the field. Some, especially in northwestern counties, were as far as 500 feet from where old records had marked them. Others have been covered over or were cut off below ground.
Seth Pelepko, the department’s well plugging division manager, said trends emerged in the searches: in the Pittsburgh region, researchers didn’t find as many wells as they were looking for, but the ones they found tended to be close to where DEP expected them to be. In the northwest, researchers found the wells quite often but they tended to be farther away from where they had been plotted.
DEP is particularly concerned with abandoned wells that intersect with population centers or places where people rely on wells for drinking water.
The study determined that only eight of the 136 wells found were leaking methane — a lower rate than had been documented in previous studies of abandoned wells, which could have something to do with differences in measurement techniques.
“Relatively speaking, the greenhouse gas footprint associated with wells according to our findings is somewhat modest,” Mr. Pelepko said. But he added that when wells leak outside of their casings it can cause a significant public safety hazard and environmental harm.
Leaking wells can cause gas to accumulate in water wells or enclosed spaces in homes, creating the conditions for an explosion.
DEP has attributed 133 stray gas migration cases between 1987 and 2013 to legacy wells, or 38 percent of all confirmed cases over that time. About 3 percent of the cases involved fracking in new wells creating a pathway to old wells that pushed fluids and pressure to shallow ground.
Those are the kinds of hazards that the state wants people to recognize through the new Allegheny County map and similar tools. With more resources, the agency hopes to expand the mapping to other counties.
While old maps are not fully reliable for pinpointing historical wells, they can illustrate patterns of well development and density to indicate areas where people should take greater care.
DEP said signs of old wells can include steel casings, valves, pump jacks, small-diameter gathering pipelines, tanks and isolated areas of subsidence.
In regions with a lot of historical oil and gas drilling, “People become a bit desensitized to old pipes and old tanks,” Mr. Pelepko said. Wells that blend into the scenery are not necessarily safe or static, he added.
The best bet is to report them to DEP so an inspector can assess them. The telephone number is 888-723-3721.
Case in point: this week, the agency is working to plug an abandoned oil well so close to an Allegheny County home that it nearly rests against the foundation. A resident noticed a smell and DEP found the well was leaking gas inside, in part because an old, poorly installed vent pipe wasn’t channeling gas away from the building.
“It was really good she called,” Mr. Beattie said.
Laura Legere: firstname.lastname@example.org.