Last week’s National Research Council report on hydraulic fracturing and earthquakes pretty much ends up where a number of scientists are on the correlation between fracking and quakes: that energy development from shale formations poses a low risk for tremors of significance. The report said more attention should be given to injection wells, which are used for waste disposal by a number of industrial enterprises, not just the oil and natural gas industry. AP science writer Seth Borenstein’s take on the report is here.
API, America’s Natural Gas Alliance and the American Exploration & Production Council have produced a couple of informational tools on hydraulic fracturing and seismic activity and underground injection control (UIC) wells that are especially timely with release of the council’s report.
Highlights from the fracking document:
Hydraulic fracturing is done with a mixture of more than 99.5 percent water and sand. The other one-half of 1 percent is chemical – including anti-bacterials and lubricants. See the FracFocus.org site for more on fracking fluids.Fracturing that occurs thousands of feet below the surface (and below groundwater aquifers) is carefully mapped with sophisticated equipment to optimize recovery of the oil and/or natural gas and to monitor the well itself. In other words, microseismic activity associated with fracking is thoroughly understood.Highlights from the UIC document:
The U.S. has about 151,000 Class II UIC wells used by the oil and natural gas industry, of which only a handful are being studied for possible links to earthquakes. These wells are a subset of more than 800,000 injection wells nationwide used to dispose of a variety of industrial wastes and for development of various minerals and geothermal energy sources. Here’s a map that shows the state-by-state well distribution:Injection wells pump fluids into deep rock formations (see graphic). It’s unusual, but in some cases a quake can occur when a number of geological and operational factors come together – especially the presence of hard, dense and brittle crystalline “basement rock.” These quakes are almost always small, below the level that would be felt on the surface.
For more information, check out the Energy From Shale website.