Oil is very valuable. Geologists, people who study rocks, look for clues that show where oil might be in the ground. They study the shape of hills, the colour of rocks, and the type of soil, to find out if they might contain oil.
This geologist is looking for oil.
Geologists search for rocks that might have oil in them. They can do this by sending sound waves and electric currents through the ground. Geologists can work out where there might be rocks with oil in them by studying how fast the waves and currents travel through the rock.
Rock samples are drilled out of the ground.
If geologists find rocks that could contain oil, they drill a small test well. A sample of rock called a ‘core’ is brought up to the surface. The rock sample is checked for oil. If there is oil in the rock, the geologists will see tiny droplets of oil clinging on to the rock, a bit like drops of water clinging on to a window after a rainstorm.
Oil is found all over the world.
Oil is found in many countries all over the world. It is found on land and under the sea. The Middle East has two thirds of the world’s known oil reserves. The amount of oil in an oil-field is measured in barrels. Saudi Arabia, in the Middle East, has 262 thousand million barrels of oil.
