Oil
Like coal and gas, oil is a fossil fuel and was formed from the remains of animals and plants that lived millions of years ago in a marine (water) environment before the dinosaurs. Over the years, the remains were covered by layers of mud. Heat and pressure from these layers helped the remains turn into what is known as call crude oil . The word "petroleum" means "rock oil" or "oil from the earth."
Today it is estimated that the world uses more than 80 million barrels of oil each day, while Australia is estimated to use around 875,000 barrels per day.
How oil is used
Once oil is extracted from the ground, it must be refined to remove impurities and water, and separate the crude oil into a range of useful oil products such as kerosene, petrol and lubricating oil.
These oil products are used for a wide variety of purposes including:
- fueling vehicles
- paving streets (asphalt)
- making clothes (nylon and other man-made fibres)
- lubricating machines (lubricating oils)
- in oil-based plastics
The following is a map illustrating the reserves of oil and gas in Australia.
Source: Image courtesy of ABARE
How is oil mined?
Most oil and gas is trapped in reservoirs deep underground. To find oil and natural gas, companies drill through the earth to the deposits deep below the surface. The oil and natural gas are then pumped from below the ground by oil rigs. They are then usually transported through pipelines or by ship.
In Australia, nearly 90 per cent of the oil and gas is located offshore under the sea. Onshore, most oil and gas has been found in South Australia’s Cooper Basin.
An oil platform is a large structure used to house workers and machinery needed to drill and then produce oil and natural gas in the ocean. Depending on the circumstances, the platform may be attached to the ocean floor, consist of an artifial island or be floating.
Generally, oil platforms are located on the continental shelf, though as technology improves, drilling and production in deeper waters is becoming more feasible. A typical platform may have around thirty wellheads located on the platform and directional drilling allows reservoirs to be accessed at both different depths and at remote positions up to 8 km from the platform.
Advantages and disadvantages
Advantages
- transporting oil to the power stations is easy.
- Technology and infrastructure is already established
- Burning any fossil fuel produces carbon dioxide, which contributes to the "greenhouse effect", warming the Earth.
- The extraction of volatile substances sometimes under extreme pressure in a hostile environment is highly dangerous.
- It is very costly to install and remove all platform rig and pipeline structures is significant.
- Oil spills cause severe environmental effects in the water.
