Wednesday, October 28, 2015

University of Vermont Releases a Study Addressing the Risks of Wellbore Communication between New and Existing Wells.

On October 20, 2015, engineering researchers at the University of Vermont released a study entitled “Potential of hydraulically induced fractures to communicate with existing wellbores” published in the journal Water Resources Research. The study estimates the likelihood for the upward migration of fracturing fluid or gas if hydraulically fractured wells were to cut across unplugged or impaired existing wells in southern New York.

At the present time, there is no high-volume hydraulic fracturing taking place in New York state because of a state moratorium dated June 28, 2015.

To calculate the probability of intersections between unconventional and existing or abandoned wells, the researchers considered the depth of a new hydraulically fractured well, the vertical growth of induced fractures, and the depths and locations of existing nearby wells. They observed that “certain regions of New York underlain by the Marcellus Shale have probabilities on the order of 1-2% of encountering existing wells, while the vast majority of regions have much lower probabilities.”

The researchers, however, pointed out that it is unlikely for fracturing fluid or gas to find migration pathways through the rock because the distance between surface formations and shallow groundwater in southern New York is large.

The researchers concluded that “the probability of encountering a well is the first step in assessing the risk of a hydraulically fractured well communicating with shallow aquifers, and places an upper bound on that risk.” 

Written by Chloe Marie - Research Fellow

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