Carbon capture and storage

Leaky Landscape: Old Oil Wells Could Threaten Carbon Injection Safety

Companies are rushing to inject carbon into Louisiana’s ground, but will thousands of abandoned wells allow it to escape?

A US Fish and Wildlife Service worker tests an abandoned well in Lacassine National Wildlife Refuge near Lake Charles, La.
Source: US Fish and Wildlife Service

Oil and gas companies spent more than a century pumping carbon out of Louisiana, leaving a landscape pockmarked with thousands of abandoned wells. Now there are ambitious plans to do the opposite: inject vast quantities of carbon back into the ground in an effort to curb climate change.

But many of the new wells will sit near the old ones, raising concerns that harmful levels of carbon dioxide (CO2) and tainted well water may escape from the increasingly porous ground. CO2 is a colorless, odorless gas that displaces air and can make breathing difficult. At high concentrations, it can cause suffocation.

“It’s not a question of whether these things are going to leak,” said Abel Russ, an attorney with the Environmental Integrity Project (EIP), a watchdog organization based in Washington, DC. “It’s a question of how much is acceptable and how much is going to be happening.”

Louisiana has the highest number of planned carbon storage wells in the country. About one-third of the nearly 200 wells undergoing permit approval across the country would be located in the state, Verite News found in a review of federal and state well applications.

While carbon capture and sequestration, or CCS, has never been tested at scale and some leakage is unavoidable, risks can be minimized by carefully selecting injection sites and designing and operating wells appropriately, many scientists who study CCS say.

Ensuring that CCS projects are safe is “baked into the approval process,” said Patrick Courreges, a spokesman for the Louisiana Department of Energy and Natural Resources. The federal government recently handed the department authority over CO2 wells in the state, a move that’s expected to trim the permitting process from about 2 years to 18 months. Louisiana isn’t trading quality for speed, Courreges said.

“If you want a permit, you still have to show us you can do it safely,” he said.

Only two other states—Wyoming and North Dakota—have been granted permit authority over CO2 injection sites, also known as Class VI wells. Carbon dioxide wells in all other states must undergo review by the US Environmental Protection Agency.

186,000 ‘Straws’
Capturing CO2 emitted from refineries and other heavy industries is a key facet of the Biden administration’s efforts to cut greenhouse gases. Billions of dollars in federal grants and tax breaks have sparked a boom in CCS projects, especially along the Gulf Coast, where a large share of the nation’s oil and gas is extracted and processed.

The region also has a massive CO2 storage capacity. According to research by the University of Texas at Austin, the sponge-like rock formations under the Gulf Coast could hold hundreds of billions of tons of carbon dioxide, “representing the largest national resources for CO2 storage and a resource capable of receiving decades of annual regional emissions, and likely national emissions,” UT Austin geologists said in a 2021 report.

Squeezing these new CO2 wells among Louisiana’s old oil and gas wells may be challenging. The state has at least 186,000 abandoned oil and gas wells. Louisiana classifies about 4,500 of these wells as “orphaned” because their operators have gone bankrupt, can’t be located, or are unwilling to maintain their sites. Responsibility for cleaning up these orphan wells falls on taxpayers.

Many wells listed as “plugged” may actually have little or nothing preventing gas from escaping, according to a report commissioned by the EIP.

Louisiana’s history of oil drilling began in 1901, but standards for well plugging didn’t take shape for another 5 decades. Before the 1950s, many wells were abandoned without seals. When companies did plug wells, they often used wood and scrap metal, or sometimes made do with old rags and mud.

The EIP report found that 13% of Louisiana’s abandoned wells, or about 24,000, were plugged before 1953, the year the oil and gas industry began urging operators to use cement and other sturdy materials when plugging wells.

“Basic information is lacking for a large number of abandoned wells, especially those plugged before the modern cementing standards instituted in 1953, and the locations of a number of abandoned wells are likely unknown,” according to the report, which was produced by environmental scientists Robert Rossi and Dominic DiGiulio in December.

All parishes with pending CO2 well permits have groupings of abandoned and orphaned wells. Across the state, about 121,000 abandoned wells are scattered over ground suitable for CO2 storage, and about 13,000 of these wells were plugged before modern cementing standards, the report said.

Russ, with the EIP, likens the wells to “a bunch of straws poking into the ground.” Many of these “straws” tap into shared spaces or interlinked rock formations. “If those straws are deep enough, that’s a direct pathway for carbon dioxide to push right back into the atmosphere,” he said.

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