Oil and Gas (O&G) activity in the U.S has had exponential growth in recent years. With the advent of more efficient extraction techniques such as fracking, the O&G industry has seen one of the largest production and export growth in the global O&G landscape. This growth, while relatively recent, is preceded by a period of U.S. O&G production that stretches back to the 80s. This frenetic activity in O&G extraction has left thousands of oil wells abandoned across the United States.
Two types of disused oil wells can be distinguished. On the one hand, abandoned wells are those that are known to the company that manages the well, but that has decided to stop exploiting it and extract resources in the area. Orphaned wells are those that have ceased to be producers and that the companies that managed that well are out of business or are unknown. According to the United States Department of the Interior, orphaned wells are extremely dangerous areas for the environment and can severely affect the public health of the area by polluting the water, and emitting harmful gases such as methane. These areas can even be affected by floods, earthquakes and explosions, thus affecting the area’s wild ecosystem. In the United States alone, the Environmental Protection Agency estimates that there may be approximately 4 million abandoned oil and gas wells across 27 states, of which more than 117,000 are considered orphaned wells. The latter means that there is no company that manages and is responsible for the environmental impact that these wells can generate. Because these wells can be abandoned for several decades, in many cases it is very difficult to find them due to the vegetation of the area or to issues inherent to the terrain where the abandoned well is located. For example, in West Virginia it is estimated that there are thousands of orphaned wells that are still not documented, in addition to the at least 6,500 wells that are documented. In the state of Texas, one of the states where much of the North American activity in oil extraction is located, the Railroad Commission estimates that there are around 8,500 inactive wells that have not yet been covered, although experts warn that there are thousands that have not yet been documented. These data warn that orphaned wells are a very serious environmental and social risk that may grow considerably in the coming years.
Many of the wells that are now inactive come from the decade of World War II and the decade of the 80s. These wells were at the time covered with steel and cement. However, this material has begun to corrode due to the corrosion effects produced by the contaminated water and oil reserves that are still in the area. Some of the wells that have already been decommissioned and plugged are once again posing an environmental problem because the materials used were inefficient to plug the well. One of the main causes of the resurgence of orphaned wells that were already properly covered may be the fracking boom. Fracking uses wastewater to fracture the source rock. The wastewater could pressurize aquifers under old wells, leading to a well explosion and bursting plugs. This reason, among others, warns that orphaned wells should be considered a priority issue for companies and the government in the United States.
One of the main barriers that make it difficult for companies to manage orphaned wells is the cost of the operation. It is estimated that the costs of plugging an abandoned well can exceed $100,000, even reaching $2 million in the event that the well cover fails and it has to be recovered and environmental cleanup and restructuring work has to be carried out in the area.
Columbia University estimates that the cost of covering 500,000 wells (around 15% of the estimated total in the United States), could exceed $24 billion. Although the cost is high, it is the companies that are the main cause of the possible damage caused by orphaned wells at an environmental and social level, so they must take responsibility for the investment in the management of this problem. However, many of these companies are unknown, or have fallen into bankruptcy. Therefore, it is the United States government in many cases that must pay attention to this problem.
As you might expect, orphaned wells are a major environmental and public health hazard. The main environmental damage is oil leaks that can affect groundwater, as well as methane emissions, which are one of the most harmful effects of climate change. In terms of public health, orphaned wells can affect recreation areas, cultivation areas, and community spaces very close to the population. According to the Environmental Defense Fund and McGill University, 4.6 million people live within half a mile of an abandoned well. Water pollution can lead to negative impacts of vegetation and wildlife on the terrain where the orphaned wells is located. Through water sampling, the San Antonio Testing Laboratory found that each liter of water tested had 0.05 milligrams of benzene, a component that oil has and is highly carcinogenic. These data suggest that immediate action should be taken to reduce the number of orphaned wells that are uncapped or inefficiently capped up.
One of the main state investments was the Bipartisan Infrastructure Law, which allocated more than 4.7 billion dollars to put the brakes on this problem. However, the cost of covering the orphaned wells currently documented significantly exceeds this amount.
Apart from the need for greater investment, it is important to consider the role of monitoring and follow-up of orphaned wells already covered. The Interior Department recommends that states control up to 5% of the wells they have plugged with federal funds, but few do. According to Dwayne Purvis, principal adviser at Purvis Energy Advisors, «we know that our cement is brittle, that steel left in the hole can corrode, and that interfaces between steel, cement and rock can separate. We know that the risk of failure must increase with time». New technologies such as drones or artificial intelligence can contribute to an improvement in the identification of orphaned wells and their subsequent monitoring.
All in all, orphaned wells may become one of the worst environmental nightmares for the United States in recent history. Greater research and investment in this area is essential to be able to curb the negative impacts that these wells may have on public and environmental health.