Unplugged: Abandoned oil and gas wells leave the ocean floor spewing methane

Unplugged: Abandoned oil and gas wells leave the ocean floor spewing methane

The Gulf of Mexico is littered with tens of thousands of abandoned oil and gas wells, and toothless regulation leaves climate warming gas emissions unchecked.

Out on the deck of a research boat, Tara Yacovitch looked out to the water. In the middle of the Gulf of Mexico, the seascape is peppered with lights. And every light is part of an offshore oil or gas platform.

Offshore platforms can vary greatly in size—some are as big as multi-storied buildings, while others resemble small but very tall rooms. The boat carrying Yacovitch and her team also housed a variety of science equipment: methane isotope readers, spectrometers, and other tools to measure methane levels in the air around these sites.

Yacovitch, an instrument scientist at Aerodyne Research, is trying to understand the scope of what some scientists say is a massive environmental issue lurking below our seas. Wells are routinely drilled into the sea floor for oil and gas production, and abandoned when they stop being economically viable—sometimes this is after years of oil or gas extraction, sometimes it’s part way through drilling before the well is even finished. But not all of these wells are plugged and properly maintained before being left behind. The result: methane and other gases leaking in unknown quantities for years on end from tens of thousands of holes in the ocean floor.

The harms for the ocean and its inhabitants, and the atmosphere above, are largely unknown. But we do know that methane is about 84 times more potent than carbon dioxide as a greenhouse gas, measured over a 20-year period, according to the United Nations Economic Commission for Europe.

An EHN analysis of federal data on oil and natural gas wells found there are 55,315 offshore in U.S. federal waters, 53,724 (97 percent) of which are in the Gulf of Mexico, according to data from the Bureau of Ocean Energy Management (BOEM) and the Bureau of Safety and Environmental Enforcement (BSEE), as of November 30, 2020.

Of those wells, 28,232, or 52.6 percent, are permanently abandoned or decommissioned. 3,444, or 6.4 percent are temporarily abandoned. And those are only in the U.S., and in federal waters alone. Individual state governments tally and record the offshore wells located in their own waters—and that data is kept separate.

Gulf of Mexico oil and gas drilling
Locations of existing oil and gas infrastructure in U.S. Gulf of Mexico territory, 2017. (Credit: Deepwater Oil and Gas Production in the Gulf of Mexico and Related Global Trends)

By Hannah Seo, Environmental Health News