New DOE study on Hydraulic Fracturing doesn't Contaminate Aquifers

The National Energy Technology Laboratory in Pittsburgh just released a study on hydraulic fracturing and its impact or should I say, lack of impact, on drinking water aquifers.  The study indicates that after a year of monitoring eight Marcellus Shale wells, that drilling fluids did not migrate into aquifers.

The year long study included the seismic monitoring of eight wells with one injected with four different tracers at different stages of the hydraulic fracturing process.  The tracers were included in the drilling fluids that were over 8,000 feet below the surface at the gas well bore.    No tracers were detected at a monitoring zone at a depth of 5,000 feet.  They monitored a separate series of older gas wells that are about 3,000 feet above the Marcellus to see if the fracturing fluid migrated up to them, and none did.

This will go along way to support the industry, but additional analyses will continue, particularly for those much shallower wells.  I have read many of the studies and reports of hydraulic fracturing. Many of the facts are ignored by numerous groups, who are anti-petroleum industry.  Here is a list of subjects that should be discussed:

• Most potable aquifers are within less than 1,000 feet of the surface (typically less than 500 feet); most shale gas producers are below 5,000 feet.
• The deeper the aquifers, the more dissolved metals and minerals in the aquifer, making the cost of stripping these metals and minerals out of the water, too costly (at the moment).
• Shale has natural gas incorporated within its molecular lattice, but can only be released through hydraulic fracturing.
• Shale has natural gas incorporated within its molecular lattice if the total organic content (TOC) is high enough.  Not all shale produces natural gas.  Exxon tried hydraulic fracturing in a large acreage package in Poland and found nothing economic.  It has left the Polish shale play.
• Shale is formed from platy clay particles (produced by a process of weathering of granites, metamorphic rocks and the re-weathering of shales) that drop out of solution in quiet waters.  These platy particles align and begin to form shales as increased pressure and temperature from burial due to the creation of overlying sediments, squeeze the water out of the molecular lattice.  The point of all this is to think of shale as a series of asphalt shingle roofs stacked on top of each other.  The thicker the shale, the more layers of asphalt shingles.  This is what makes shale impervious and impermeable; making any kind of fluids penetrating the formation incredibly difficult. 
• Shale tends to become plastic-like with increased temperature and depth, up to the point that the both begin to metamorphose the molecular structure into slate (which is brittle).   
• There is never any discussion by the writers about the pressure used in hydraulic fracturing versus the overburden pressure that must be overcome. 

At the end of the day, there are thousands of feet of overlying sediments exerting a lithostatic pressure that exceeds the pressure employed in hydraulic fracturing.  Thereby limiting the propagation of fractures in the upward direction.