About Fracking & Safety
Hydraulic fracturing — “fracking” — begins with drilling a well-shaft down to the required level. Then one or more shafts are drilled horizontally (or roughly horizontally) from that point. When drilling through aquifers, the crews install a steel “casing” system around the wellbore and cement it in place. This provides an impermeable protective layer between the well and the surrounding environment, including any water sources.
Once the well is drilled, cased and cemented (see the diagram below), small perforations are made in the horizontal well pipe(s). Through those, a typical mixture of water (90%), sand (9.5%) and chemical additives (0.5%) is pumped at high pressure to create micro-fractures in the rock. These are then held open by the grains of sand, so that the “locked-in” natural gas can be freed. It then flows back to the surface, where it can be captured.
The additives help to reduce friction (thereby reducing the amount of pumping pressure from diesel-powered sources at the surface, which reduces air emissions) and also prevent pipe corrosion and boost well efficiency. Many such additives are chemicals that are in common use in our households. To learn more on this topic please visit FracFocus Canada.
Once the fracturing operation is finished, the well is considered completed and is now ready to produce natural gas for years to come, sometimes decades. The fracking process has been used for more than 70 years (since 1947), and has been applied to more than 1.7 million wells in the U.S. alone.
A common misunderstanding about fracking relates to fears that the process may contaminate drinking-water aquifers. But in BC the fresh-water aquifers are usually located less than 300 meters underground, while shale gas reservoirs are at depths of 2,000 to 3,000 meters, beneath layers of rock through which fracking chemicals could not migrate “upwards.” The aquifers are also protected by the steel and cement casings of the gas wells.
Thus the BC government’s BC Oil and Gas Commission, which regulates and supervises fracking in BC, and limits the use of water, says:
“There has never been an instance of groundwater contamination due to hydraulic fracturing in British Columbia.”
And that goes for Canada, too!
Earthquakes? Fracking can produce minor “seismic events”, but let’s not call them all “earthquakes”. Only one in many thousands of them can be felt at the surface. Even when they are felt at the surface, it’s typically no more than the vibration of a heavy truck or train passing by.
If there’s a stronger seismic event attributable to fracking, the BC Oil and Gas Commission orders the operation shut down until the problem is sorted out. So, all in all, the risks from fracking are far less than those claimed by fear-mongering critics. That said, there’s always room for more scientific research, as a report to the BC government said in early 2019.