Researchers backed by the Environmental Defense Fund and led by McGill University’s Jade Boutot are showing how a combination of drones, magnetic sensing, methane detection and on-the-ground verification can locate the many oil and gas wells that have been lost to time in Pennsylvania.
Survey combines remote sensing and boots-on-the-ground
Pennsylvania has been an oil and gas producing state for more than a century, and that long history has left regulators with a daunting inventory problem. Official records list about 30,000 wells, but researchers say the true number of undocumented or “orphan” wells may reach as high as 300,000. The new study tested a multi-technology approach to find wells that no longer appear on maps or in modern permitting databases.
The project, titled Multi-technology Detection of Undocumented Orphaned Oil and Gas Wells, deployed an array of tools during a large-scale survey in Pennsylvania. Teams flew drones over targeted areas while using magnetic sensors and methane detection systems to identify likely well locations. Field crews then visited suspect sites to confirm whether wells existed and to characterize conditions on the ground.
Why finding wells matters
Many of the wells drilled before contemporary recordkeeping are now concealed by vegetation, eroded structures or remote terrain. Left unlocated, these abandoned wells can leak methane and other hazardous substances into soil, groundwater and the atmosphere. The new research demonstrates that remote-sensing platforms, when combined with focused field investigations, can substantially improve the likelihood of finding these hidden sources of pollution.
- Remote detection: Drones provide rapid aerial coverage and high-resolution imagery for areas that are rugged or densely vegetated.
- Geophysical sensors: Magnetic surveying helps identify subsurface metal casings and disturbance patterns consistent with wellbores.
- Methane tracing: Specialized detectors pick up subsurface or surface methane anomalies that may indicate leaks.
- Verification: On-site inspection confirms the presence and condition of wells flagged by remote systems.
The research team included experts from the Pennsylvania Department of Environmental Protection, Lawrence Berkeley National Laboratory, the National Energy Technology Laboratory, Los Alamos National Laboratory and the technology firm Sawback Technologies, in addition to academic partners. Environmental Defense Fund sponsored the study, and the work was led by Boutot at McGill.
Implications for remediation and policy
Pinpointing undocumented wells is a necessary first step before regulators can assess risks and plan plugging activities. Locating and verifying wells reduces uncertainty around where resources should be deployed to protect drinking water, limit methane emissions and reduce long-term liability from legacy infrastructure.
Federal and state programs that fund well plugging and site reclamation could benefit from more cost-effective search methods. By narrowing large tracts of land to specific target locations, the multi-technology approach helps avoid the expense of blanket surveys and reduces the time needed for site prioritization.
| Category | Figure |
|---|---|
| Documented wells | 30,000 |
| Potential undocumented wells | Up to 300,000 |
While this study focuses on Pennsylvania, the techniques tested could be adapted for other older oil- and gas-producing regions across the United States. The method’s scalability will depend on terrain, vegetation cover, historic drilling density and the availability of trained field crews to confirm remote detections.
As states and the federal government consider expanding programs to plug orphaned wells and to curb methane emissions, the new findings offer a practical roadmap for how emerging technologies can be integrated with traditional fieldwork to locate and prioritize legacy sites.
