Methane has a larger impact on global warming than carbon dioxide. Some states are releasing a lot of it through abandoned oil and gas wells, but a new study finds Wyoming is not one of them.
According to University of Wyoming atmospheric science researcher Jeff Nivitanont, orphaned wells are abandoned by their parent companies without being plugged up. There are 2-3 million abandoned oil and gas wells across the U.S., but they weren't included as a source of methane emission until recent studies, like one in Pennsylvania.
"They estimated that in Pennsylvania alone, it could make up between five and seven percent of the state's total methane emissions," said Nivitanont. "Not taking that into account is quite significant when you look at the models, and you look at air quality, those sorts of things."
In Pennsylvania, orphaned wells emit about 11 grams of methane per hour, which is similar to an average dairy cow. But Wyoming's emission rate was unknown. This could be a big deal because the state is home to around 1900 orphan wells.
To find out, Nivitanont and his team measured ten wells in the Powder River Basin. They found the rate was much lower-- near 0.6 grams per hour. That's less than one percent of the total methane emissions from oil and gas in Wyoming.
"If regulators in the future are going to be crafting policy around these emission rates, we want it to be correct," he said. "We're just trying to fill in those gaps."
Nivitanont said the difference could be because Wyoming's wells are a different type and younger than those elsewhere. But he also added some of the wells in the state are still high emitters and should be sealed.
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