Which rock is fracked for gas and oil?

shale. Shale holds gas and oil but is impermeable.

What is pumped into the well during fracking?

water, sand and chemicals. It is pumped in at very high pressure.

What does the high pressure do?

fractures the shale. Cracks give the gas a way out.

Which is a benefit of fracking for a country?

it has to import less fuel. Producing its own fuel gives energy security.

Which is a limitation of fracking?

it can contaminate ground water. The chemicals and the waste water are the concern.

Why can gas in shale not be reached by an ordinary well?

shale is impermeable, so the gas cannot flow through it. The rock has to be cracked before anything can move.

Fracking · Cambridge IGCSE Environmental Management revision

In plain words

Shale holds gas and oil like a sponge that will not let go. Fracking is the method of cracking the rock open to let them out. It has made some countries rich in energy, and it has been banned in others.

9 things to know

Fracking is the extraction of natural gas or petroleum from shale rock by hydraulic fracturing.
Shale is impermeable, so the gas and oil trapped inside it cannot flow to an ordinary well.
A well is drilled down to the shale, and then sideways along it. A mixture of water, sand and chemicals is pumped in at very high pressure.
The pressure fractures the shale. The sand holds the cracks open. Gas or oil flows out through the cracks and up the well.
Benefits. It reaches gas and oil that could not be extracted before. A country can produce its own fuel and import less, which is called energy security. It creates jobs, and it can lower the price of gas.
Gas releases less carbon dioxide than coal for the same energy, so swapping coal for gas lowers emissions.
Limitations. It uses very large volumes of water. The chemicals may contaminate ground water. The waste water that returns is toxic and must be treated.
Fracking can cause small earthquakes. Methane, a greenhouse gas, can leak from wells. There is noise and heavy traffic near the site.
The gas and oil are still fossil fuels. They are finite, and burning them releases carbon dioxide.

Worked example

A government is deciding whether to allow fracking. Give one argument for and one against, and reach a conclusion.

For: the country would produce its own gas, so it would import less and gain jobs.
Against: the process uses a great deal of water and risks polluting the ground water that people drink.
Conclusion: it could be allowed only away from drinking-water supplies and with strict monitoring. A conclusion needs a reason, as here.

Tips and tricks

"Hydraulic" means using liquid under pressure. The fracturing is done by the pressure of the water, not by explosives.
Do not call fracking renewable or clean. It produces a fossil fuel.

6 questions, about 2 minutes.

It lands in your notebook with its questions as flashcards.

Fracking: 6 questions and answers

These are the quiz’s questions. Do the quiz first, then come back here for the ones that got you.

Which rock is fracked for gas and oil?
- granite
- limestone
- shale (the answer)
- marble
Shale holds gas and oil but is impermeable.
What is pumped into the well during fracking?
- air and steam
- water, sand and chemicals (the answer)
- oil and sand
- concrete
It is pumped in at very high pressure.
What does the high pressure do?
- melts the rock
- dissolves the gas
- cools the well
- fractures the shale (the answer)
Cracks give the gas a way out.
Which is a benefit of fracking for a country?
- it is a renewable resource
- it uses no water
- it reduces the amount of methane in the air
- it has to import less fuel (the answer)
Producing its own fuel gives energy security.
Which is a limitation of fracking?
- it can contaminate ground water (the answer)
- it floods large valleys
- it produces radioactive waste
- it works only when it is windy
The chemicals and the waste water are the concern.
Why can gas in shale not be reached by an ordinary well?Stretch
- the gas is frozen
- shale is too close to the surface
- shale is impermeable, so the gas cannot flow through it (the answer)
- the gas is dissolved in sea water
The rock has to be cracked before anything can move.

6 questions

Tap an answer and you’ll see straight away whether it’s right, and why.

Worksheet

3 questions, 7 marks. Write your answers on paper, then check them.

Fracking

Cambridge IGCSE Environmental Management 0680 · 7 marks · papermunch.org

Name ______________________________ Date ______________

Define the term fracking.[2]
Show answerHide answer
The extraction of natural gas or petroleum from shale rock by hydraulic fracturing.
I got this one
Explain why sand is added to the liquid used in fracking.[2]
Show answerHide answer
The sand enters the cracks made in the shale. It holds them open so the gas or oil can flow out.
I got this one
Describe three environmental limitations of fracking.[3]
Show answerHide answer
Any three: it uses large volumes of water; chemicals may contaminate ground water; the waste water is toxic; it can cause small earthquakes; methane can leak; there is noise and traffic.
I got this one

Answers: Fracking

1. The extraction of natural gas or petroleum from shale rock by hydraulic fracturing.
2. The sand enters the cracks made in the shale. It holds them open so the gas or oil can flow out.
3. Any three: it uses large volumes of water; chemicals may contaminate ground water; the waste water is toxic; it can cause small earthquakes; methane can leak; there is noise and traffic.