Researchers are taking to the archives — and the air — to track down abandoned oil and gas wells that have left little evidence on the surface or aren’t marked in modern records.
The Pennsylvania Department of Environmental Protection is gathering maps made over the last century from the file drawers of other state agencies, municipal records offices and drilling company libraries. It is also sharing information with the National Energy Technology Laboratory, whose researchers flew a helicopter outfitted to detect metal casings in old wells over three state-owned properties this summer.
The department’s goal is to digitize both old and new maps, and merge them in a public online tool that drilling companies can use to scope out hazards before extracting gas from new wells.
DEP’s list of verified orphaned and abandoned wells includes fewer than 8,700 sites, but the agency estimates that 200,000 unaccounted for wells were drilled and abandoned during decades of oil and gas activity before wells were registered in the state. Pennsylvania began requiring operators to get permits to drill new wells in 1956 and to register old wells in 1985.
That doesn’t mean the location of many of the wells is entirely unknown. Oil and gas companies have passed down and shared old maps for generations, but no one has ever consolidated and digitized all those private libraries.
“The goal is to have available a one-stop shop, one location where any operator could access information on legacy wells, historical sites,” said Seth Pelepko, the chief of the subsurface activities section of DEP’s oil and gas program. “This tool would be a way to ensure that the universe of potential sites is available to operators in the state.”
The mapping project has new urgency because proposed state regulations call for drilling companies to identify and monitor abandoned wells around their operations before and during hydraulic fracturing, or fracking.
Abandoned wells are potential pathways for air and water pollution. Some spew methane on their own or when they are disturbed by modern drilling operations. State regulators have compiled an incomplete tally of seven recent cases when new wells interfered with abandoned ones, including instances when gas or fluids erupted from old wells as companies fracked new wells nearby.
In one case in Fayette County in 2008, fracking unsettled an abandoned well beneath a major electrical transmission line, causing a significant power disruption, DEP said. In another, in Westmoreland County in 2008, methane escaped through an abandoned well into the soil in a residential neighborhood after a company fracked a conventional well nearby.
This could take awhile
DEP initially expressed hope that the map would be ready when the proposed regulations take effect, but regulators now say that timeline is too ambitious. A first draft of the final rule is likely to be finished by the end of the year, with an effective date expected in mid-2016.
While some companies have submitted historical maps to DEP, including valuable archives kept by EQT Corp. and Peoples Natural Gas, other companies have been reluctant to participate in the effort, citing cost, time and a host of thorny legal issues.
Several of the state’s oil and gas trade organizations detailed their legal concerns to DEP: State or federal regulators might take enforcement action against companies that contribute maps if they reveal old wells that haven’t been properly plugged or reported; third parties, like citizens or environmental groups, might use the map as the basis for appealing new well permits; and companies that contribute to the map might open themselves to lawsuits by people harmed while using the information or who claim that they have a proprietary interest in the data.
“Any person or entity contributing scanned copies of old maps or digital files containing well spots without specific protection from various claims by third parties and enforcement by Pa. DEP or federal agencies will be reluctant to participate in this project,” an attorney wrote in March on behalf of the Marcellus Shale Coalition, the Pennsylvania Independent Oil and Gas Association, and the Pennsylvania Grade Crude Oil Coalition.
The department’s proposed rules for identifying orphaned and abandoned wells are among the most contested in the broad regulatory update the agency is working on now.
Companies generally support rules requiring them to try to identify old wells — something they routinely do anyway as they plan where to put new wells — but some details of the department’s proposals are unpopular in the industry, such as the requirement to send questionnaires to nearby landowners to ask them for information about abandoned wells on their property.
The trade groups said the proposed regulations for identifying abandoned wells should be revised before the map is developed, but DEP intends for the tool to enhance companies’ ability to search for wells, not replace the other search-and-monitoring procedures outlined in the proposed rule.
“Without having all the stakeholders working on this problem, DEP necessarily has to approach it differently,” Mr. Pelepko said. “We will continue to work and try to identify sources, and we will continue to archive those sources as the time and resources allow, but there may be a different timeline for accomplishing the end goal because of that.”
Old maps less than trustworthy
DEP has already posted data online with over 30,000 potential historic oil and gas well locations derived from mining maps drawn between 1900 and the 1930s. With that collection and others, the agency cautions that the information is a guide of unknown accuracy and is “in no way a substitute for actual field observations.”
One of the industry groups’ concerns is that old maps can be unreliable. They might detail wells that were never drilled and leave out wells that were.
The truly missing wells are the ones that were drilled and shut from the mid-1800s through the early 1900s that never made it onto a map.
“There were many wells drilled in the early days of the industry that were plugged in the early days of the industry before anybody even really knew,” Penneco Oil Co. chief operating officer Ben Wallace said. “Those wells are the ones that are causing problems today.”
Twice in four months this year, the Delmont-based company fracked new horizontal oil wells in Greene County into just those kinds of unknown abandoned wells.
In both cases, the abandoned wells did not appear on the historical maps Penneco consulted, and there was nothing visible on the surface of the ground to mark them. The wells had been plugged during an era when sealing off unproductive wells meant stuffing the holes with wooden posts, burlap sacks, dirt and gravel.
Interviews were done with older residents in the area before drilling to ask if they knew of any unmapped wells or remembered their grandparents mentioning them.
“The old-timers didn’t know they existed,” Mr. Wallace said.
The first case, in April, did not apparently affect any waterways, but sludge from an old well reached a stream during the second incident in July. The company is plugging the two abandoned wells to meet modern standards.
The problem is particularly acute for companies like Penneco that are borrowing some of the technologies that allow unconventional drillers to coax gas from stubborn shale — horizontal drilling combined with hydraulic fracturing — to extract oil from the same, shallower rock formations pursued by legacy drillers in the past.
“If the historical development was at least as deep or deeper” than contemporary drilling, “certainly the risk would be elevated in that situation,” Mr. Pelepko said.
Marcellus Shale wells drilled from the same pads as Penneco’s oil wells would have traveled 4,000 feet deeper to get to their target and would have been unlikely to interact with the abandoned wells, Mr. Wallace said. Penneco’s wells were drilled into the same, 3,700–foot-deep formation as the unmapped, ancient wells.
“Had we known, had we had a record of these wells, we actually would not have drilled the lateral there,” he said. “We would have crossed it off the project.”
Mr. Wallace said his company learned from the two incidents that if it studies patterns of legacy wells from old maps it can make better assumptions about where wells were likely left out of those old records.
“It’s a learning experience trying to anticipate antiquity,” he said.
Laura Legere: email@example.com