Petroleum is a combustible mineral oil embedded in the ground and is an essential fuel and raw material today. It is known as the world's three major natural energy sources with coal and natural gas.

The cause of oil has always been a topic of discussion among experts.

After a lot of scientific research and investigation, scientists generally believe that a long, long time ago, the warm climate of the earth's regions bred many tiny low-level organisms.

When organisms died, their bodies were deposited at the bottom of oceans or large lake basins and buried by sediment. These remains grew thicker and thicker and were cut off from the outside air.

Over an extended period, geological forces and the intense combination of high temperatures and pressures deep within the Earth, along with intricate bacterial decomposition, led to the formation of oil.

When oil was first formed, it was just many scattered oil droplets. Along with groundwater flow, they are constantly flowing from one rock layer to another.

Finally, they flowed to a place surrounded by dense rock layers. This place does not allow the oil to evaporate, nor does it allow it to be lost.

More and more oil gathered here, and an oil field was formed.

In general, most of the rock formations that can produce oil are shale and mudstone.

What people call an oil field is not a huge hole filled with oil.

Instead, the oil droplets usually seep out of the holes and crevices in the rock surface little by little, along with water. Because oil is lighter than water, it floats on top of the water and sometimes seeps out of the ground.

What is oil exactly good for?

Two-thirds of the world's oil is now used to make piped gas and the fuel needed to run cars, ships, and other vehicles.

The rest is used to heat homes and commercial areas, and a small portion is used to make chemicals.

Oil and LPG can be used to make basic chemicals such as methane, ethane, ethylene, and benzene.

These petroleum products are polymerized to make plastics, rubber, synthetic fibers, detergents, fertilizers, and other industrial and agricultural products and household goods.

What happens when oil runs out?

Petroleum is a non-renewable energy source. At present, half of the world's oil reserves have been developed and consumed.

According to the Organization of Petroleum Exporting Countries (OPEC), it is predicted that by around 2050, the earth's oil will be depleted.

Scientists will address this problem from a variety of sources:

One is to expand the field of petroleum geological exploration to the depths and oceans.

The second method involves expediting the hydrocarbon conversion of organic matter within sediments and artificially synthesizing the process of oil formation.

The third is to design a new type of automobile, using electricity or solar energy, etc, as a driving energy source to replace oil.