What Is Fracking? | National Geographic

shale formations underlie much of the
United States they are the source of
natural gas and oil historically the
formations have been difficult to drill
today it’s possible with the technology
of fracking in North Dakota’s Bakken
formation fracking started in 2006
nearly eight thousand active wells now
dot the landscape deep underground
horizontal pipes stretch up to two miles
long the Iverson well drilled in 2010
illustrates the fracking process the
well plunges nearly two miles down with
cement and steel casing inserted to
prevent leaks into groundwater the well
curves when it reaches the Bakken layers
of shale that sandwich a layer of
sandstone the pipe follows the sandstone
because that’s where shale oil collects
fracking begins by forcing plastic balls
down the well the balls open sleeves in
the pipe to expose holes fluid is then
pumped down the well under extremely
high pressure the fluid shoots through
the holes and fractures the rock over
the course of three days this well
fracked the rock 29 times the burst show
where fissures were created
once fracking is done oil is released
and flows up the well the used fluid
which contains toxic materials flows up
with the oil some of the fluid is
recycled the rest is pumped into
disposal wells deep below ground water
the long-term environmental effects of
fracking are unknown but in coming years
the number of wells in North Dakota is
expected to jump from today’s 8,000 to
50,000
you