Transcript Katrina and Tarina Oil

1.What is
oil?
And…
2. How does it
come to be
underground?
water
Dead sea creatures
Most of the world is covered by
sea. In the sea there are tiny
animals and plants that are called
planktons. They get their energy
to live from the sunlight. When
they die they sink to the bottom of
the sea. Millions of years latter
they become they oil and gas.
The dead sea creatures are
buried by sand and mud at the
bottom of the sea. The sun's
energy is stored in the bodies of
the dead creatures and plants.
Then the dead bodies start to
rot.
Sand
Squashed sea creatures
Over millions of years the dead animals and plants are buried
deeper and deeper. The squashed creatures turned into oil
and gas.
The pressure and temperature deep underground turned the
chemicals from the rotted animals and plants into crude oil
and gas.
Balloon
Oil and gas can get trapped in layer
underground such as where the rocks
are folded into an umbrella shape.
Oil and gas can move through the porous rocks
(rocks with gaps between the grains).
The oil and gas move upwards from the source
Cap rock
rock where they were formed.
When they met a layer of cap rock
(a rock with no spaces between the
grains) the oil and gas are trapped.
Oil and gas
Reservoir Rock
Source Rock
Oil and gas in
spaces
Oil well
A well is drilled so that the crude oil and other liquids
travel up the hole. When it comes to the surface the crude
oil has to be moved closer to where the oil is.
Finding oil and gas trapped deep underground and drilling a
well are very complicated and expensive. It costs millions
pounds (3 million New Zealand dollars)
to drill a well and only a few are successful. The liquids
found underground can be a complicated mixture of water,
crude oil and gas. The crude oil and gas need to be
separated before they can be transported safely.