Speaker 1: Hi. I am Tracy V. Wilson and I'm Holly Fry.
Speaker 1: We are the co hosts of the Stuff You Missed
Speaker 1: in History Class podcast from how Stuff Works dot com.
Speaker 1: And as you might suspect from the name, what we
Speaker 1: like to talk about are the things that are of
Speaker 1: historical significance but maybe you didn't hear about in your
Speaker 1: standard history class. So sometimes they are famous figures and
Speaker 1: we're talking about the lesser known parts of their lives.
Speaker 1: Sometimes they are people in groups and places that are
Speaker 1: often overlooked in history class. Lots of cool stuff, So
Speaker 1: come and join us. Welcome to brain Stuff from how
Speaker 1: Stuff Works. Hey, brain stuff, this is Christian Seger fracking.
Speaker 1: You've heard of it, you know it's controversial, but you
Speaker 1: might not know what it actually involves. Never fear. Here
Speaker 1: at brain Stuff, we're going to put some fracking knowledge
Speaker 1: in your brain. Fracking is the delightfully cheeky sounding nickname
Speaker 1: for hydraulic fracturing, which sounds a little bit less delightful
Speaker 1: and less cheeky and more like something you would do
Speaker 1: to your enemies. And I don't know StarCraft, but no,
Speaker 1: it is something we do to rocks in the simplest terms.
Speaker 1: Hydraulic fracturing is a way of getting more of the
Speaker 1: valuable fluids like oil and natural gas out of geologic
Speaker 1: formations under the ground. Deep under Earth's surface, there are
Speaker 1: deposits of rock that have huge reserves of oil and
Speaker 1: natural gas within them. But these fossil fuels aren't like
Speaker 1: big lakes where you can just stick a straw in
Speaker 1: and suck it. Is not a milkshake. No, these reserves
Speaker 1: of oil and natural gas are found locked up in
Speaker 1: pores distributed throughout vast layers of rock like shale. So
Speaker 1: how do you get them out at a reasonable pace? Okay,
Speaker 1: different processes are used, but let's look at the typical
Speaker 1: fracking set up for something like shale gas. You start
Speaker 1: with a deep vertical well, drilling a hole down to
Speaker 1: the level of the shale that you want to mind.
Speaker 1: The depth will vary, but just for example, one company
Speaker 1: claims it's average fracking well depth is seven thousand, seven
Speaker 1: hundred feet. That's deep almost one and a half miles
Speaker 1: or about two point three kilometers. When you're at the
Speaker 1: right depth, you take a nine degree turn and you
Speaker 1: continue to drill horizontally parallel to the target rock layer.
Speaker 1: This horizontal section of the well can also travel thousands
Speaker 1: of feet. Now here's where the fracturing comes in. First,
Speaker 1: you open up holes in the horizontal section of the pipe.
Speaker 1: Then you vigorously push a liquid cocktail known as fracking
Speaker 1: fluid down into the borehole under high pressure. This fracking
Speaker 1: fluid is usually a mixture of water, some chemical additives
Speaker 1: like acids to help dissolve the rock, and gels to
Speaker 1: thicken the fluid, and finally solid particles called profits. And
Speaker 1: we're going to get to those profitts in a second.
Speaker 1: When the mixture reaches the horizontal section of the pipe,
Speaker 1: it bleeds out through those holes into the surrounding rock,
Speaker 1: and the extremely high pressure causes the rock to form
Speaker 1: tons of little fractures or cracks. Through these cracks, the
Speaker 1: reserves of fossil fuels contained in the rock can escape
Speaker 1: into the well to be pumped back up to the surface.
Speaker 1: What once was entombed in ancient rock is now the
Speaker 1: way to powering your car or heating the water for
Speaker 1: your next shower. And those propins I mentioned, which are
Speaker 1: often just grains of sand, they help prop the cracks
Speaker 1: in the rock open, so the Earth's precious bodily fluids
Speaker 1: continue to escape into the well without the miners applying
Speaker 1: continuous pressure, So that's how it works. But then there's
Speaker 1: the entirely separate question of whether fracking is a good idea.
Speaker 1: It's mega controversial in many parts of the world. Some
Speaker 1: people claim it consumes too much fresh water, and they
Speaker 1: worry about what will be done with the fracking fluid
Speaker 1: after it's been used, and some opponents wonder if it
Speaker 1: will create earthquakes or cause chemical contaminants to leak into
Speaker 1: our groundwater. Check out the brain stuff channel on YouTube,
Speaker 1: and for more on this and thousands of other topics,
Speaker 1: visit how stuff works dot com.