Once a well has reached the end of its productive lifetime, it is supposed to be properly shut down and sealed. Then the area around the well is supposed to be returned as much as possible to the way it was before the well was drilled. This process is called “Plugging and Abandoning.” The majority of modern oil and gas wells are plugged and abandoned properly.

However, oil and gas wells have been drilled in this country since the 1800s, so there are quite a few wells that reached the end of their production run well before any laws were in place to require them to be properly closed. In addition, some modern oil and gas wells were not properly plugged and abandoned, despite existing mandates. In most cases, these unplugged oil and gas wells are not owned and registered by anyone, making them “orphaned” wells.

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The Problem

So why are these orphaned oil and gas wells such a problem? Orphaned wells result in both safety and environmental problems, and those problems are difficult to rectify because the original owners are no longer around to take responsibility for them. That frequently means that no one knows where the well is either. And it is hard to properly plug and abandon a well if no one knows it’s there. That also means that no one is quite sure just how many of these orphaned oil and gas wells there even are.

Some of the problems orphaned oil and gas wells create are safety related. In addition to the well itself, which is a very deep hole in the ground, unremoved infrastructure or pits at the surface can injure people or animals; cars or tractors can get stuck and damaged; and the well can even cause trouble for new construction projects.

On the environmental side, groundwater movement associated with an unplugged well can contaminate local well water and ecosystems. Another significant issue is that unplugged orphaned oil and gas wells can emit greenhouse gases to the atmosphere, exacerbating climate change. Methane, one of the primary products of an oil and gas well, is 25 times more potent a greenhouse gas than carbon dioxide.

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Find the Wells, Find the Solution

So how is the USGS helping with this? The first step is getting a handle on how many orphaned oil and gas wells there are across the country. Because these wells can be on private, state, Tribal or Federal lands, even knowing how many orphaned wells that have been identified there are can be a challenge.

To help with that, the USGS created the U.S. Documented Unplugged Orphaned Oil and Gas Well Dataset, which centralized data for all known orphaned oil and gas wells from 27 states and the Federal government that were known up until 2022. In addition, the USGS worked to make sure that each identified orphaned oil and gas well had the same information, such as its location and identification number.

The dataset has more than 117,000 orphaned oil and gas wells in it. The majority are located in Appalachian Basin states, the central Midwest, and western Gulf Coast.

This dataset will also play into efforts by the Department of the Interior, Department of Energy, and others to plug and remediate the orphaned oil and gas wells. The Bipartisan Infrastructure Law included $4.675 billion to help address orphaned oil and gas wells, and the data that the USGS has collected will help the responsible agencies identify where best to put that money to good use.

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Next Steps

Of course, the known orphaned oil and gas wells are only part of the problem. There are also quite a few orphaned oil and gas wells that have not yet been found. The Interstate Oil and Gas Compact Commission estimates the number of undocumented orphaned wells to be between 310,000 and 800,000. That means the ones we know about are, at best, around a quarter of the total.

The USGS is working with the Department of Energy, the Bureau of Land Management, state geological surveys, and other agencies to help identify undocumented orphaned oil and gas wells. From using airborne geophysical surveys to find magnetic anomalies that could indicate the presence of a well, to using lidar surveys to “see” through dense vegetation and find abandoned oil and gas infrastructure, the USGS is bringing all of its expertise to bear to assist with the challenge.

In addition, the USGS is working to quantify the environmental effects of orphaned oil and gas wells, including groundwater contamination and how much greenhouse gases are escaping from the orphaned oil and gas wells. The Well Done Foundation has partnered with the USGS to analyze samples of gases that have been collected at orphaned wells so that scientists can estimate what is actually reaching the atmosphere.

Addressing orphaned oil and gas wells in the United States is an enormous task, but progress will hinge on strong science, and the USGS is working hard to provide that science. To keep up-to-date on USGS energy science, visit the USGS Energy Resources Program Website, sign up for our newsletter and follow us on Twitter.