When an oil or gas well is no longer in use, it must go through a permanent sealing process called plug and abandonment, or “P&A”. Sealing the well is extremely important to protect against environmental dangers like groundwater contamination and methane emission. Unfortunately, P&A can be a complex project, and there is currently a backlog of abandoned and orphan wells in the United States waiting to be permanently sealed.
Why Plug a Well?
Once an oil or gas well stops producing at a profitable level or the well is no longer needed, drilling companies will leave the well and move to the next project. If the well is not properly plugged, methane and other gases can leak from the well, contaminating local groundwater and negatively impacting the atmosphere. Plugging a well usually involves completely filling it with cement and restoring the land around it.
Are A lot of Wells Abandoned?
A recent estimate from the Environmental Protection Agency (EPA) places the number of abandoned wells in the United States at over three million, and over 330,000 of those wells are in the state of Pennsylvania. Most states and the federal government have legislation in place that require well owners to complete P&A on their wells. Usually, this involves the owner paying a bond to build the well, which they forfeit if they abandon the well without P&A. But while there is regulation around well abandonment, there are some reasons why a well may remain unplugged.
Well owners may be in bankruptcy or lack the funds to complete the project, leaving the abandoned well unplugged or filled with improper materials, such as wood. P&A is a costly process, and each well may cost anywhere from $20,000 to $145,000 to seal. It could potentially cost $435 billion to properly seal all the abandoned oil and gas wells in the United States. While that figure seems daunting, legislatures and contractors are working in tandem to create programs that control the cost of P&A and positively impact the environment.
Groundwater Contamination
One of the most dangerous risks of leaving an abandoned well unplugged is the potential to contaminate the groundwater in the area surrounding the well. If unplugged, a well can release toxins into the groundwater for years, even decades. This can have devastating effects on not only the wildlife and livestock in the area but also pollute residential drinking water supplies for nearby towns.
If groundwater becomes contaminated, it Is extremely difficult and expensive to remediate. The EPA estimates that clean up can cost up to $770,000 per year and take as long as six years to complete.
Methane Emissions
In addition to groundwater contamination, unplugged wells can emit dangerous greenhouse gases, such as methane. Methane can cause heat to be trapped in the atmosphere and is a primary contributor to climate change and global warming. Climate change is responsible for extreme weather fluctuations in recent years, including devastating floods, tornadoes, and hurricanes that cause billions and billions of dollars in damage each year.
It is estimated that the abandoned wells in the United States emit up to 281 kilotons of methane per year. The global warming potential (GWP) of methane is 34 times that of carbon dioxide over a 100-year period and 86 times more harmful over a 20-year period. Plugging abandoned wells plays a crucial part in controlling climate change because it creates a drastic drop in the annual emissions of methane and other gases.
Other Toxic Pollutants
Other toxic substances like arsenic, sulfate, benzene, and chloride can also be released from an unplugged abandoned well and pollute air or groundwater. These substances pose harmful health risks to surrounding residents and can contribute to chronic issues like asthma and headaches.
What Are the Other Benefits of P&A?
The Energy Infrastructure Act passed by Congress in 2021 provides roughly $4.7 billion to be awarded through grants to provide P&A across the United States. Columbia University’s Center on Global Energy Policy and Resources for the Future conducted research in 2020 and estimated that a federal P&A program could create as many as 120,000 new jobs nationwide. So, in addition to being extremely important to the environment, P&A projects can have a positive economic impact in communities that may have seen a downturn when the wells in their area were abandoned.