INTENSIVE SAMPLING OF A METHANE-RICH RESIDENTIAL WATER WELL OUTSIDE THE MARCELLUS SHALE DEVELOPMENT REGION, MONTOUR COUNTY, PA

With the introduction of hydraulic fracturing in Pennsylvania, it is no surprise that dissolved gas sampling efforts have become increasingly common. Most often, these sampling efforts involve analyzing single samples collected from multiple wells and comparing dissolved gas concentrations and compositions from samples collected at different times and locations. This makes it difficult to determine how concentrations of dissolved gases such as methane are influenced by environmental conditions such as barometric pressure, humidity, air temperature, height of the water column, and water temperature. In order to examine the relationship between methane concentrations in well water and environmental variables, we have initiated a six month project in Montour County, PA, in a location far from hydraulic fracturing activities. We are in the midst of weekly sampling at a residential water well containing naturally occurring methane. In situ analyses include pH, temperature, dissolved oxygen, conductivity, and height of the water column. Air temperature, humidity, and barometric pressure data are also collected from two weather stations located within a 15-mile radius of the sampled water well. Alkalinity and acidity of filtered samples are determined within hours of sampling. Filtered subsamples are preserved for later laboratory analysis of seven anions and six simple cations using ion chromatography. Both filtered and unfiltered subsamples are acidified (pH<2) and analyzed for 11 metals using ICP-OES. Triplicate dissolved gas samples are collected using Isotech dissolved gas bags (IsoBags®) and preserved for analysis by gas chromatography. During the first nine weeks all inorganic chemical parameters have been fairly constant when the samples were collected, as have the following environmental parameters: water temperature (11.8-12.5°C) and barometric pressure (29.64-30.19 in. Hg in Danville, PA). The average pH of 9.44 is relatively high as compared to previously published values for groundwater samples in the Williamsport region. We plan to initiate gas analyses in early 2014. It remains to be seen if variable environmental conditions can be correlated with changes in methane concentrations.