Why it's so hard and expensive to plug an abandoned well

July 29, 2021 GMT

An estimated 2 million abandoned oil and gas wells across the country, forgotten or ignored by the energy companies that drilled them, are believed to be leaking toxic chemicals. Many of the wells are releasing methane, a greenhouse gas containing about 86 times the climate-warming power of carbon dioxide over two decades. Some are leaking chemicals such as benzene, a known carcinogen, into fields and groundwater.

Here are some questions and answers.

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WHAT IS AN ABANDONED WELL?

An oil or gas well is considered abandoned when it’s reached the end of its useful life and is no longer producing enough fuel to make money. If the company that owned the well went bankrupt, or there’s no owner to be found to plug or maintain it, then the abandoned well is considered “orphaned.”

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WHAT DANGER DOES AN ABANDONED WELL POSE?

Over time, the amount of oil and gas a company can extract from a well declines. At that point, many operators will cap a well to seal it temporarily. Sometimes, wells sit in that “idle” or “inactive” state for months or even years. But to prevent chemicals from leaking into the air or soil, a well must be properly plugged with cement. Left unplugged, oil and gas wells are at risk of leaking methane into the atmosphere and toxic chemicals into groundwater.

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HOW DO YOU PLUG AN OIL AND GAS WELL?

The idea is to fill certain parts of the well with cement, to stop toxic chemicals from leaking into aquifers or the air, and to eventually bury the well underground.

First, crews must remove any pumpjacks or other equipment that might have been left at surface. They then examine the well for problems: leaks, deteriorated casings, cracked cement. They fish out random sticks or debris that might have wedged over time into the wellbore — the vertical shaft that is drilled to extract oil and gas.

“If you leave a well ignored for a long enough time, the casing begins to deteriorate inside,” said Luke Plants, chief operating officer at Plants and Goodwin, a company that plugs oil and gas wells throughout Appalachia. “Every kid that walks by and sees this open pipe throws a rock down in there.”

Next, the pluggers must measure the wellbore and determine to what depths they must pour cement to keep the well from leaking into water tables or other underground geologic formations.

The older the well is, the trickier the operation. When a well is orphaned, detailed records of how the well was drilled might be missing. The crews must try to determine, based on records of nearby wells, what is occurring underground. If a well had been abandoned decades ago, crews might have to build roads to move heavy equipment needed for the job. If a well is found under a driveway or a parking lot, crews must operate carefully around homes, schools or electric wires.

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WHAT DOES IT COST?

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The cost to plug an orphaned well varies depending on its age, depth and location. In North Dakota, where some wells are drilled to depths of more than 20,000 feet, it can cost $150,000 to plug a single well and restore the land around it. In Pennsylvania, the state budgets about $33,000 to plug each well.

Many states require companies to post bonds to pay for well plugging. But the bond amount is generally far lower than the cost of plugging. On federal lands, the average amount the government held in bonds was just $2,122 per well in 2018, according to the Government Accountability Office. Some groups are pushing states to tighten rules on how long a well can remain idle or to raise the bond amounts required of operators.

An effort in 2005 to obtain funding from Congress for a federal well-plugging program failed to secure much money. Many states, including Texas, Pennsylvania, New Mexico and North Dakota, fund their plugging operations through fees or taxes paid by the oil and gas industry. But that money isn’t enough to plug all the wells that need it. And state lawmakers often face pushback from groups that would rather have that money go to education or other community needs.

In Pennsylvania, plugging all the known orphaned wells could cost $250 million to $300 million, said Seth Pelepko, the environmental program manager at the Bureau of Oil and Gas Planning and Program Management in the Pennsylvania Department of Environmental Protection. But his office has secured only enough money to spend about $1 million annually. Pelepko estimates that plugging all the wells there — including those of unknown location — could range into the billions of dollars.

In Colorado, state regulators spent $14.4 million over three years to plug and reclaim wells after operators had set aside only $1.3 million, according to the Western Organization of Resource Councils, a network of grassroots groups involved with land stewardship. Colorado would need about $5.3 million a year for five years to address the current inventory of orphaned wells, the group said.