(classical music)
(chalkboard writing)
- Fracking, you've heard of it,
you know it's controversial.
But you might not know
what it actually involves.
Never fear, we're here to put
some fracking knowledge in your brain.
Fracking is the delightfully
cheeky-sounding nickname
for hydraulic fracturing,
which sounds a little bit less delightful
and more like something you do
to your enemies in StarCraft.
But no, it is something we do to rocks.
In the simplest terms,
hydraulic fracturing
is a way of getting more
of the valuable fluids,
like oil and natural gas,
out of geologic formations
under the ground.
But these fossil fuels
aren't like big lakes
where you can just stick
a straw in and suck.
These reserves of oil and natural gas
are found locked up in pores
distributed throughout vast
layers of rock like shale.
So how do you get them
out at a reasonable pace?
Let's look at a typical fracking set up
for something like shale gas.
You start with a deep
vertical well, drilling a hole
down to the level of the
shale that you want to mine.
The depth will vary but just
for example, one company claims
its average fracking
well depth is 7,700 feet.
That's deep!
Almost one and a half miles
or about 2.3 kilometers.
When you're at the right depth,
you take a 90 degree turn
and continue to drill horizontally,
parallel to the target rock layer.
This horizontal section of the well
can also travel for thousands of feet.
Now here's where the fracturing comes in.
First you open up holes
in the horizontal section of the pipe.
Then you vigorously push a liquid cocktail
known as fracking fluid
down into the borehole
under high pressure.
This fracking fluid is
usually a mixture of water,
some chemical additives like
acids to help dissolve the rock
and gels to thicken
the fluid, and finally,
solid particles called proppants.
We'll get to those in a second.
When the mixture reaches the
horizontal section of the pipe,
it bleeds out through the
holes into the surrounding rock
and the extremely high
pressure causes the rock
to form tons of little
fractures or cracks.
Through these cracks, the
reserves of fossil fuels
contained in the rock
can escape into the well
and be pumped back up to the surface.
What was once entombed in ancient rock
is now on the way to powering your car,
heating the water for your next shower.
And those proppants I mentioned,
which are often just grains of sand,
help prop the cracks in the rock open
so the earth's precious bodily fluids
continue to escape into the well
without the miners having to
apply continuous pressure.
So that's how it works.
But then there's the
entirely separate question
of whether fracking is a good idea.
It's really controversial
in many parts of the world.
Some people claim it
consumes too much fresh water
and worry about what will be
done with the fracking fluid
after it's been used.
And some wonder if it
will create earthquakes
or cause chemical contaminants
to leak into our groundwater.
So what do you think about fracking?
Let us know in the comments
and subscribe if you want
to keep learning more.
And that's the fracking
truth, so say we all?
- [Group] So say we all!
- Frack!
