NORM (naturally occurring radioactive materials)

Shale is a fine grained sedimentary rock formed from clay that has been subjected to great pressure. The organic matter in black shales is the material that generates the gas.  But in seawater and sediment geochemistry, the organic material also has an affinity for attracting radionuclides, mainly uranium.  While not exactly glow-in-the-dark radioactive, the black shales do contain NORM above background levels. In fact, the drillers target intervals for horizontal boreholes and hydrofracturing based on radioactivity measured with a wireline gamma ray log. 


There are two concerns with NORM in the Marcellus.  The first is that the drill cuttings from the horizontal boreholes are often from the most radioactive zones in the formation.  There are many tons of these generated from borings that may be thousands of feet long.  The concern is that radionuclides are leaching from these cuttings as they are exposed to oxygen and rain water in the pits (see PITS). 

The second NORM issue is the possible entrainment of radionuclides in the flowback water.  The Marcellus Shale Committee funded a study last year with the Gas Technology Institute to analyze flowback fluid samples from 19 wells.  The report came out in December, but has not been widely released.  They did not report any NORM values, or even a gross alpha, which is routinely measured on drinking water.  When asked at a meeting in April why they hadn't reported NORM, they responded that because of the high TDS in the samples, they could not get a proper analysis on radionuclides.  To measure radionuclides, the water has to be filtered a certain way to separate and concentrate them. 

 So the question of NORMs is still up in the air.

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