Louisiana drilled more coastal oil wells than any other state. Thousands have sunk in the Gulf.

A new analysis from The Times-Picayune | The Advocate reveals the extent of drilling in the fragile land along Louisiana's coast.

• By ALEX LUBBEN | Staff writer  nola.com

Mikeal Berthelot, Jr., was navigating the mouth of the Mississippi River in his shrimp boat, a stretch of water he’d traversed many times before. The water was calm. The sun beat down. His deckhand was making a peanut butter sandwich.  

Then the boat slammed into something they couldn’t see. The crash threw Berthelot Jr. forward. As he grasped for support, his hand shattered a glass pane in front of the steering wheel. 

“My boat is stuck on something,” he told his father over the phone. “It went through the bottom of the hull.”   

Within minutes, the engine room filled with water. Within an hour, the boat had sunk.  

Berthelot didn’t know it at the time, but he had struck an old oil well, drilled more than a half-century ago. Back then, the site was surrounded by marsh.  Today, it’s in navigable open water.    

There are thousands more like it. An analysis by The Times-Picayune and The Advocate, independently reviewed by researchers at Tulane University, estimates more than 3,600 wells once drilled on land or in wetlands are now in open water — a result of decades of erosion, sinking land and rising seas.   

Some leak. Many endanger boats. Hundreds may fall to taxpayers to clean up.  

As land peels away from oil and gas wells along Louisiana’s eroding coastline, they become increasingly difficult and expensive to plug, inspect and maintain. The state has not fully contended with the growing costs of plugging a fleet of wells in open water and keeping them plugged permanently — nor with the environmental hazards that these wells may pose.  

As a result, Louisiana is left with a graveyard of old wells pocking its disappearing coasts, sinking into the Gulf with the rest of the once-vibrant marsh.

 “It's a lot more expensive to plug a well in water as opposed to on land,” said Mark Agerton, a researcher at the Center for Energy Studies at Rice University in Houston who has studied the costs of plugging oil and gas wells in Louisiana. “The environmental risks are high in these ecologically sensitive areas along the coast.”    

While decades of drilling have helped fuel the economy of the state and the nation, the industry has also played an important role in coastal land loss and climate change, which is causing rising seas.  

Louisiana’s coastal wetlands contain more oil and gas wells than anywhere else in the U.S. The prospect of plugging them has long been a concern for the state, but less attention has been paid to what is disappearing under the tides.  

Neither the Louisiana Oil and Gas Association (LOGA), which represents smaller oil and gas companies, nor the Louisiana Mid-Continent Oil and Gas Association (LMOGA), representing the majors, responded to requests for comment.

LOGA has previously supported federal funding to plug oil and gas wells. 

Louisiana has 7,583 unplugged wells in its offshore and inland state waters, according to a study published in Nature — more than Texas, Alabama and California combined. The total does not include offshore wells in federal waters, which begin three miles off Louisiana’s coast.  

Louisiana has relied heavily on federal aid, particularly through the Biden-era Infrastructure Investment and Jobs Act, which has funded the plugging of hundreds of wells. But the state only has about $246 million in state funds earmarked to plug wells in its waters, the Department of Energy and Natural Resources said. That’s only enough to plug about 850 wells — roughly 11% of the total number. 

Spills in coastal waters, particularly in wetlands, are hazardous and costly to clean up. Oil suffocates plants, accelerating land loss and harming ecosystems.

Patrick Courreges, a DENR spokesperson, said that the agency has no system for tracking whether wells along the coast were drilled on land but are now in open water, though the department began to log whether wells are on land or in water in 2021.  

Tracking wells as the coast disappears  

Using archived maps from the U.S. Geological Survey and historical records, The Times-Picayune analyzed wells drilled between 1932 and 2016 across two dozen coastal parishes.  

Of nearly 84,000 wells drilled over that period, 3,654 were likely drilled on land or in marsh and are now in open water. Most are permanently plugged — their wellhead has been removed and the wellbore is plugged with cement casings — but hundreds are not.  

Only 12 of the 3,654 still produce oil.  

These figures are rough estimates, constrained by gaps in state records and the limitations of historical coastline maps, the oldest of which are based on grainy aerial photographs from the 1930s. Locations data for older wells can sometimes be off by more than 1,000 feet, according to Scott Eustis, the community science director at Healthy Gulf, a nonprofit environmental advocacy organization and co-author of an upcoming study about abandoned oil and gas infrastructure.  

The state has lost 610 wells that couldn’t be located and so could not be plugged. Still more are likely completely undocumented, drilled before modern rules went into effect, according to the state’s legislative auditor.   

Mead Allison, a professor in Tulane’s Department of River-Coastal Science and Engineering, reviewed The Times-Picayune’s methodology and called it “scientifically valid.”

The analysis is likely an undercount of the number of wells that were drilled on land and are now in water. The most recent coastal map is from 2020, and land loss has continued since then. The analysis also excludes wells that are very near to land, and many wells exist right at the edge of land or marsh. 

Still, the best-available data shows what’s already happened and makes clear what’s to come.  

It isn’t hard to find hazardous wells. Just a few miles north of where Berthelot’s boat sank, Well 307 rusts above the waterline in Quarantine Bay.

“It’s coated in oil,” Eustis noticed as he inspected it in early June. It was leaking. 

It had been drilled in 1980 and temporarily plugged on Aug. 27, 2005, “an auspicious date,” Eustis said — just two days before Hurricane Katrina made landfall less than five miles away.

Twenty years later, Well 307 hasn’t been turned back on. 

The company that owns the well, Cox Operating, is going through bankruptcy proceedings in Texas. Another company may buy up Cox’s assets, including Well 307. If no one does, the well will likely become orphaned, and responsibility for plugging it will fall to the state. 

Rising costs  

Paul McKim described how he maneuvered his small barge through the swamp to a well he was hired to plug, where he found a botched job: instead of poured cement, someone had stuffed a few bags of powdered cement into the borehole. 

 “That’s how they plugged them back then,” he said. “We had to drill them out” to plug the well properly.   

Plugging a well in water can cost four times as much as plugging one on land. In about four feet of water, it can cost about $400,000, said McKim, the owner of Crescent Energy, a company that plugs wells in Louisiana and Texas. On land, the same job might cost just $100,000. McKim’s clients are mainly oil companies; he also plugs orphan wells, funded by federal dollars. 

The average cost across all wells in Louisiana is $113,000, according to the state’s legislative auditor. The state’s DENR said that its orphan well program had plugged 70 wells on water since 2014 at an average cost of $287,000.  

Plugging wells properly is highly technical. Crews remove any remaining parts of the wellhead above ground, puncture the casing with dynamite, and inject high-pressure cement to seal the well deep underground. That allows them to place multiple cement plugs at precise depths inside the wellbore. 

The goal is to prevent oil or gas from migrating into groundwater or the surface and isolate it deep underground, ideally forever.  

Many older wells were never plugged to modern standards. In the early 20th century, companies sometimes sealed wells with “well-seasoned pine wood,” according to a 2023 report prepared for the Environmental Integrity Project. It wasn’t until 1941 that Louisiana began requiring cement plugs. 

The Times-Picayune identified 437 wells that appear to have been drilled on land, are now in open water, and were likely plugged before that requirement took effect, according to DENR data. Those older wells are more likely to leak, and may need to be monitored or re-plugged. But the DENR said that it does not reinspect plugged wells unless it receives a report indicating the need.   

A financial gap  

When a well is drilled, oil companies legally must set aside money to plug it once it runs dry. But state law requires companies to post far less money than it actually costs to plug a well, especially for older wells now in water.  

When a well is drilled on land, oil companies often set aside less than 10% of the cost of actually plugging the well. And many operators are covered by “blanket” policies — lump-sum guarantees for entire fields that can be as low as $50,000 for dozens of wells, according to the legislative auditor.  

For some of the oldest submerged wells, there may be no money set aside at all.   

“Financial security wasn’t even a thing until 2000,” said Courreges, the DENR spokesperson. “Industry had a 100-year head start with no financial security requirements.”  

Plugged but still risky  

Plugging may ultimately not be enough in a shifting, sinking landscape.   

“Damn near every coastal oil field has sunk two or three feet due to fluid withdrawals of the oil and gas,” said Greg Miller, a former oil industry professional and founder of ICON Environmental, a consulting firm.

That slow movement underground can stress a well’s structure, even if it was sealed correctly.   

Louisiana law requires well casings to be cut at least 10 feet below the mudline in state waters. If the casing is cut too shallow — or if the well was on land when it was plugged and so was cut to a shallower depth — the pipe may still protrude, posing a navigational hazard. That may have been what happened with the well that sank Berthelot’s boat.   

But even a proper cut and deep cement job offers no absolute guarantee.  

“There is a high probability, but not a certainty, that it won't leak for, quote, ‘some time,’ unquote,” said Anthony Ingraffea, a professor emeritus of petroleum engineering at Cornell University.    

 'We had nightmares'

 While the state wrestles with the burden of old coastal wells, the Berthelots have been left to shoulder a burden of their own.  

After the boat sank, they spent about $40,000 hiring divers and a barge with a crane to fish it out of the Gulf.  He and his son hoped to rehabilitate it and make it seaworthy again, but it cleaved in two during the salvage process.  

They tried, unsuccessfully, to get compensation from a company that once owned the well.   

“We went through all this trouble, we had nightmares,” Berthelot, Sr. said. “But the boat just blew up like a bomb."