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.
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