Millions of undocumented methane-leaking oil wells identified using drones

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An army of drones fitted with the right equipment could be used to detect millions of unplugged oil wells, many of which remain undocumented and spew carbon dioxide into the atmosphere, researchers have said.

A team from Binghamton University estimates that New York State alone has an estimated 35,000 abandoned oil or gas wells, while Pennsylvania has more than 600,000 which date back to the early days of drilling.

Overall, the United States has an estimated two million orphaned wells which release methane - a potent greenhouse gas - into the atmosphere, alongside other chemicals such as benzene, carbon tetrachloride and chloroform.

“If all the orphaned and abandoned oil and gas wells in New York State were plugged, the equivalent of nearly 750,000 metric tons of carbon dioxide could be removed from the atmosphere, which is the equivalent of removing the cars of Buffalo for one year,” said Binghamton researcher Timothy de Smet.

Left uncapped, these wells also make it difficult to re-stimulate older oil fields with newer technologies such as hydraulic fracturing (aka fracking).

In 1879, New York State became the second state in the country to require plugging wells after their useful life has ended. That plugging requirement was poorly enforced until modern regulations came to the state in 1963 and what constituted “plugging” in those early days was crude by modern standards.

De Smet said that the locations of older wells were often recorded on inaccurate hand-drawn maps and there are many under-reported well sites or recorded wells that ended up never being drilled.

To find abandoned wells, the researchers outfitted a drone with a magnetometer that can detect magnetic anomalies in the wells’ metal casings, pinpointing their location.

Before the technology could be deployed in the larger field, they first needed to do multiple smaller test trials to ensure that the process works as intended. For example, every drone has a unique magnetic and electromagnetic interference signal that needs to be compensated for, de Smet explained.

The team has been testing the technology as a way to detect unexploded military ordnance in Ukraine, and used advanced signal processing methods to determine the optimal parameters necessary to increase the signal-to-noise ratio.

They adapted the drones to find oil wells and managed to locate 72 wells in Cattaraugus County, New York State, in just over three hours.

“We could actually have flown the drone faster and for longer missions, but this was the first time we’d tested this so we were pretty conservative with mission planning,” de Smet said.

Long-term, the New York State Department of Environmental Conservation plans to adopt this strategy to locate abandoned wells, which the agency will then plug.

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