McGill University researchers are leading an international team whose goal is to create a framework to help governments in the US and around the world assess and prioritize remediation strategies for orphaned oil and gas wells.
These inactive wells represent environmental risks because they have the potential to contaminate water supplies, degrade ecosystems, and emit methane and other air pollutants that are harmful to human health. But plugging the wells also offers various potential environmental opportunities such as underground storage of carbon dioxide and hydrogen or the development of geothermal energy systems.
Dealing With Orphaned Wells—An Incomplete Picture and Insufficient Money
There are hundreds of thousands of orphaned oil and gas wells in the US, at least 400,000 in Canada, and tens of millions of them around the world. Because the former owners of these abandoned wells cannot be traced or cannot clean up these wells, the responsibility for plugging the wells typically falls to governments who may need further information on how best to manage the orphaned wells.
In November 2021, as part of the Bipartisan Infrastructure Law, the US government allocated $4.7 billion to plug orphaned oil and gas wells across the country.
“While this sounds like a lot of money, we estimate that the costs of plugging the documented orphaned wells in the US will exceed this sum by 30–80% or possibly more,” said Mary Kang, an assistant professor in the Department of Civil Engineering at McGill University and the senior and lead author of the paper published in Environmental Research Letters that lays out some of the environmental risks and opportunities of various remediation strategies, as well as the information that still needs to be gathered.
More Than 4.5 Million Americans Live Close to Unplugged Gas or Oil Wells
To gain a sense of the larger effects of these wells and help inform government policies, the researchers analyzed data for more than 80,000 documented orphaned oil and gas wells in the US while at the same time looking at available socioeconomic, environmental, and natural resource data. Hundreds of thousands more of these orphaned wells are spread across the country.
They found that more than 4.6 million Americans (or about 13% of the nation’s population) live within 1 km of one of the more than 80,000 documented orphaned gas or oil wells in the US. Among this population, at a national level, there was an over-representation of Hispanic/Latino and Native American populations. The researchers also found that more than one-third of these wells are at about 1 km from a domestic groundwater well, though they note that there is generally insufficient data about the potential health risks associated with orphaned wells.
Environmental Opportunities—Wind Power, Subsurface Gas Storage, and Geothermal Development
The subsurface is a natural resource like any other, and many present-day as well as future applications will require access to subsurface reservoirs that are not compromised by oil or gas leakage. For example, the researchers found that most of the documented orphaned wells (91%) are in areas where geologic formations offer subsurface storage potential for carbon dioxide, hydrogen, and natural gas as long as they meet security standards. The researchers also suggest that, instead of restoring the surface to predevelopment conditions, the land could be repurposed to produce wind power, because almost 75% of the orphaned wells are in areas with top wind capacity. In addition, approximately 33% of orphaned wells are in regions, such as North Dakota, that are considered moderately favorable to geothermal systems and 1% are found in areas such as Utah, Colorado, and California that are considered most favorable for geothermal development.