Messin with things we shouldn't

The Safe Drinking Water Act (SDWA) of 1974 (EPA, 2011) establishes minimum standards to protect tap water in the US. It includes protection for both surface and underground sources of established drinking water and also potential sources of drinking water. First, I'd like to address storing natural gas in empty gas wells in the Marcellus Shale bed in PA. This shale bed is found throughout the Allegheny Plateau region in North America and contains potential natural gas reserves. This was once the main oil producing region in the US and currently an area where fracking is controversial. (Trivia time: PA is the "Quaker State", which explains the motor oil's name. PAs peak oil production was in 1891 and could produce enough oil to power the US for 7 months. Of course now it would only last 3 hours.)



What is really interesting about this area is that people are concerned with well water contamination around this storage site. The USGS studied this after problems were noted as early as 2001 (Breen, et al., 2007, p. 12). In the Tioga River Valley the USGS team identified isotopes unique to the stored natural gas in wells that drew water from the aquifer underlying the area. These aquifers are an important drinking water source in this region and partially recharged by the Tioga River. It turns out the stored gas migrated through fault lines unique in the Marcellus Shale to people's drinking water sources. It took several years for the USGS to determine the impact of storing the natural gas in depleted wells something the project team may not have considered during the NEPA process or even had this time-frame in mind. It is also interesting to note how closely related the geology of this region is with its water sources. Because of the fractures in the Marcellus Shale unusual things can happen like this example.


I bring this up because if stored natural gas can migrate to a well or aquifer, what is hydraulic fracturing doing? If an area is over-pressurized a fracture in the bedrock occurs and the natural gas/methane follows a route of least resistance. Something to think about.