Although it is expected that hydraulic fractures would propogate upward little further than the top of
the Marcellus, one ought to consider the potential impact if there were sufficient pressure from hydrofracturing to connect to and open existing fractures up to very shallow depths,or to connect them with shallow, improperly abandoned wells. Fractures remain open during pressurization from hydrofracturing, for a few hours at a time for up to a few days, then remain open if proppant sand has entered the fractures. If fractures did connect to existing fracture networks, they would not have sufficient proppant to keep them open after hydraulic fracturing was complete. To date migration through such fractures of fracturing fluids and produced water has not been documented