|USGS photo/ public domain ~ Fracking site on Marcellus Shale in PA|
Last week the University of Vermont released a new study showing that methane from active fracking sites can escape through faults that connect to preexisting, abandoned oils and gas wells. The study, to be published in Water Resources Research on October 20, showed that methane release measured at abandoned wells near fracking sites can be significant but did not investigate how the process occurs.
In August, the EPA proposed measures that would cut methane and VOC emissions from the oil and natural gas industry and clarify permitting requirements. These regulations would help combat climate change, reduce air pollution that harms public health, and clarify Clean Air Act permitting requirements for the oil and natural gas industry, says EPA.
Since then, the industry has been hotly debating the proposed regulations on limiting release of methane during fracking operations. That debate, says James Montague, an environmental engineering doctoral student at the University of Vermont who co-wrote the paper, “needs to take into account the system that fracking operations are frequently part of, which includes a network of abandoned wells that can effectively pipeline methane to the surface.”
The researchers studied an area in New York state underlain by the Marcellus Shale formation, which had been fracked until a ban went into effect in the state in the summer of 2015. They used a mathematical model to predict the likelihood that the hydraulically induced fractures of a randomly placed new well would connect to an existing wellbore, putting that probability between .03 percent and 3 percent.
Since then, industry-sponsored information published vastly increased assumptions about the area impacted by a set of six to eight fracking wells known as a well pad - to two square miles -- increasing the probabilities cited in the paper by a factor of 10 or more.
Not all abandoned wells provide a pathway to surface for methane. But given the large number of abandoned wells, even a small percentage can potentially pose an environmental risk. You can read their abstract here.