Tiki's Quick Guide to Fracking
What is fracking? It's a way of squeezing yet more fossil fuels out of our planet. The word 'fracking' comes from 'hydraulicWhat does 'hydraulic' mean?Hydraulic means using a fluid, usually water, to transmit a force. A car's braking system is operated by hydraulics and there are thousands of other uses. In a car when the driver pushes on the brake pedal, she is pushing a small piston in a cylinder filled with fluid. The force she exerts on the fluid runs through metal pipes to small cylinders and pistons on each road wheel. The movement of the pistons forces the brakes to apply and slows or stops the car fracturing'. The fuel in question is usually called 'natural gas' or just 'gas'Gaseous confusionNot to be confused with gasoline, often just called 'gas' too but gasoline is a liquid fuel - also called petrol - which is what most cars run on. Confusing, isn't it!.
Normally, natural gasWhat is 'natural gas'?It is a gas called methane made up of chemical elements carbon and hydrogen. That's why it's called a hydrocarbon. This gas burns very well in air and so people use it as a major source of energy comes out deep boreholesalso called a 'well' (as in 'oilwell') drilled to get at underground reservoirs of the gas (and usually oil too). The gas comes to the surface very easily because it's at high pressure deep down. If you shake up a bottle of fizzy drink and then take the top off, the frothy gas comes gushing out. Natural gas from a normal drilled well behaves just like this. But petroleum geologistsWhat are petroleum geologists?'Petroleum' means 'oil' and a geologist is a scientist who understands about rocks in the Earth's crust and, in particlar, how to find oil and gas deposits deep underground have discovered that there's a huge amount of natural gas trapped in rocks called shaleShale is a sedimentary rock. It started off as mud when it formed millions of years ago, usually on an ancient seafloor. Over time and with the weight of all the later sediments (like sandstone or limestone) above it, it has turned into a rock; a process called lithification. If you bore a hole through it, the gas doesn't come out. You know it's there so how do you get it out? This is where fracking comes in.
Petroleum engineers have become very smart in the way they can About drillsDrills are tools which bore deep holes in the rocks in order to get at valuable stuff like water, oil or gas. The drill has a special cutting 'bit' on its end and is connected by an ever-longer set of metal rods back up to the surface. Here, machines spin the rods round to make the bit far below spin and so grind its way through the rocks. As the drill bores deeper, engineers at the surface drilling rig fit more rodsdrill holes deep into the rock formations which lie beneath our feet. They can now get the drill to bend round so that it can chew its way at any angle, even flat (horizontal). This means they can accurately drill for a long way through a flat-lying 'bed' of shale with the trapped gas in it deep down below. What's more,they can repeat this in different directions from the main borehole at the surface. Then the fracking starts. Engineers first must carefully 'case'What is casing?Casing in made of a series of steel pipes which line the well to prevent the escape of fracking fluids and gas. The steel casing is usually made stronger and more leak-proof by injecting concrete the well to prevent leaks and pollution of water-bearing rocks at shallower levels. Then they pump a fluid water with sand and special chemicals in it at very high pressures through the holes they have drilled in the shale deep below. This actually breaks up the shale by making lots of tiny fractures. Because the fracking fluid contains sand grains, the fractures can't close again because the sand grains prop them open. When the fracking is completed, the shale gas begins to flow out of the fracked rock bringing the fluidThe fracking fluid has to be separated out and stored in tanks or ponds so that it can be treated by having pollutants removed with it. Some shales are rich in oil so oil is released as well as gas. And that's it. The shale gas, as it is called, is then pumped along pipelines to wherever it's needed just as with 'normal' natural gas.
Is fracking good or bad? As you'd guess, there are two sides to this. Some people think it's wonderful and others think it's going to be a disaster. Let's look at the good points first.
Fracking: the good stuff
And the bad...
So kids: what do you reckon? You'll be the ones who benefit from fracking... or not. Why not add your view to my poll (right side of this page)!
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Tiki's Fracking Video Theatre: how fracking works and reaction to it from environmentalists around the worldHydraulic fracturing
Frack Off Extreme Energy Action Network (UK)