As Pennsylvania weighs a new DEP rule that would expand leak detection and repair requirements for oil and gas producers, there’s new research on the integrity of relatively low-producing “stripper” wells. Such facilities would remain exempt under Pennsylvania’s current rulemaking, but a University of Cincinnati study suggests they’re among the leakiest well sites in Appalachia. We speak with the author, Dr. Amy Townsend-Small.
As natural gas-producing states adopt tighter controls on supply-chain carbon emissions, the science of methane detection is advancing by leaps and bounds. These days, gas producers can easily sniff out wasteful and potentially dangerous gas leaks using sensors, infrared cameras, and other high-tech gadgets. Soon, you’ll even be able to see methane plumes from space, through the eyes of a research satellite being built by the Environmental Defense Fund. Thanks to all this innovation, many companies are already investing in new technology and shoring up their own leak-detection practices. Not only do such improvements help protect public health and safety, they also save those companies money by preventing loss of product.
That’s all great – it takes a lot of sophisticated gear to pinpoint trouble spots in a large, modern natural gas operation. The trouble is, some of the industry’s worst leaks happen at older, smaller operations.
In the U.S., the most common type of oil-and-gas well is the marginal, or “stripper,” well, which produces less than fifteen barrels of oil (or the equivalent) per day. While Pennsylvania is moving towards more comprehensive emission controls on larger gas facilities, a new study shows these low-producing wells are contributing far more than their share to the industry’s overall climate impact.
Last year, a team led by Dr. Amy Townsend-Small of the University of Cincinnati looked at methane and VOC emissions from marginal wells in eastern Ohio, and found many venting even more gas into the atmosphere than their total reported output. The study also found that these wells contribute disproportionate amounts of methane and VOCs relative to the amount of energy produced. The study estimated that wells in this lowest production category emit approximately 11% of total annual methane from oil and gas production in the EPA greenhouse gas inventory, despite only producing about 0.2% of oil and 0.4% of gas in the U.S. per year.
“There were just open vents, things like that, that could have been remediated if they were inspected more often.”
According to Dr. Townsend-Small, there are about 10,000 marginal oil wells in Pennsylvania, many of which are over 100 years old and have been largely abandoned.
“These old wells are not monitored or inspected like newer wells are,” she said. “These stripper wells are scattered around the landscape, including in parks and people’s yards, so they can be a health hazard.”
The study measured around 50 wells. About half of them emitted very little or no methane, while a small number of “super emitter” sources were responsible for the majority of the emissions. While age of the well was not found to have a correlation with the amount of emissions, the study found that most of these high-emitting sources were poorly maintained.
“I think these proposed regulations, if they were expanded to low producing wells, could go a long way.”
“The highet one we saw, a tree had fallen on the well head, so that could have been the cause of the high emission rates,” said Dr. Townsend-Small. “Or there were just open vents, things like that, that could have been remediated if they were inspected more often, potentially.”
When it comes to policy interventions to reduce emissions from these wells, one of the most effective and simplest solutions is increased inspection and maintenance.
“Just making sure vents are closed would make a big difference,” said Dr. Townsend-Small.
Closing the current loophole in DEP’s rulemaking and including regulations for low-producing wells would do just that.
“I think these proposed regulations, if they were expanded to low producing wells, could go a long way, and it could also produce employment opportunities to produce leak detection jobs,” she said.