Like most states, the data from the Pennsylvania Department of Environmental Protection do not explicitly tell you which wells have been hydraulically fractured. They do, however, designate some wells as unconventional, a definition based largely on the depth of the target formation:
An unconventional gas well is a well that is drilled into an Unconventional formation, which is defined as a geologic shale formation below the base of the Elk Sandstone or its geologic equivalent where natural gas generally cannot be produced except by horizontal or vertical well bores stimulated by hydraulic fracturing.
While Pennsylvania has been producing oil and gas since before the Civil War, the arrival of unconventional techniques has brought greater media scrutiny, and at length, tougher regulations for Marcellus Shale and other deep wells. We know, however, that some companies are increasingly looking at using the combination of horizontal drilling and hydraulic fracturing in much shallower formations, which could be of greater concern to those reliant upon well water than wells drilled into deeper unconventional formations, such as the Marcellus Shale. The chance of methane or fluid migration through karst or other natural fissures in the underground rock formations increase as the distance between the hydraulic fracturing activity and groundwater sources decrease, but the new standards for unconventional wells in the state don’t apply.
The following chart summarizes data for wells through May 16, 2014 that are not drilled vertically, but that are considered to be conventional, based on depth:
Note that there have already been more horizontal wells in this group drilled in 2014 than any previous year, showing that the trend is increasing sharply.
Of the 26 horizontal wells, 12 are considered oil wells, five are gas wells, five are storage wells, three are combination oil and gas, and one is an injection well. These 177 wells have been issued a total of 97 violations, which is a violation per well ratio of 62 percent. 429 permits in have been issued in Pennsylvania to date for non-vertical wells classified as conventional. Greene county has the largest number of horizontal conventional wells, with eight, followed by Bradford (5) and Butler (4) counties.
We can also take a look at this data in a map view:
Conventional, non-vertical wells in Pennsylvania. Please click the expanding arrows icon at the top-right corner to access the legend and other map controls. Please zoom in to access data for each location.