Offshore oil rig in the Gulf of Mexico
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More than 14,000 unused oil and gas wells remain uncapped in the Gulf of Mexico. Leaks from wells can harm marine ecosystems and increase global warming methane emissions, but it costs billions of dollars to plug them.
Mark Agerton of the University of California, Davis, and his colleagues collected data from the US Safety and Environmental Enforcement Agency on 82,000 wells drilled in the Gulf of Mexico. Although most wells are plugged and abandoned, over 14,000 wells were found to be unplugged, even though they had not been used for at least five years.
Operators are legally obligated to block wells that have ceased production. This usually includes a cement cap covered with sediment. A little over 5000 wells remain active.
Oil leaks from oil wells, especially from the nearest shore, can harm marine ecosystems. Wells near the coast can also leak methane, which can reach the atmosphere. Researchers also found that methane leaking from deep-sea wells further offshore is mostly consumed by marine microbes.
The 2010 Deepwater Horizon oil spill, caused by a natural gas eruption from a temporarily capped oil field, represents a worst-case scenario. But unlike that well, many of the unplugged wells are tapped out, and it’s unclear what impact many small, chronic leaks might have. No,” he says Agerton.
The Infrastructure Bill, which passed the U.S. Congress in late 2021, spent $4.7 billion to plug isolated onshore and offshore wells, but David Pettit of the National Resources Defense Council says all wells will be plugged. “No chance,” he said.
Researchers estimate that plugging all the inactive wells would cost more than $30 billion. Plugging the shallow water wells alone would cost about $7 billion. For wells in federal waters, the oil companies that drilled them are responsible for plugging them. They remain on Hook even if the well they drilled is sold to a smaller operator who cannot afford to plug it. may become a state expense.
Researchers say US agencies should focus their efforts on shallow water wells that pose the greatest threat to the environment and are the cheapest to plug.
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