The Petroleum Lifecycle: Formation, Refining, and Uses

The Origin and Formation of Petroleum

Petroleum has been known for thousands of years, and deposits are found deep within the earth. This oil contains stored solar energy accumulated over millions of years.

Plants get their energy from the sun through the biological process of photosynthesis, and animals derive their vital energy from plants or other animals. In other words, the final energy source for life is solar.

Oil energy is stored in the small spaces or pores of certain sedimentary rocks, similar to how water is retained in a sponge-like rock. This rock was originally submerged in the sea, and its pores were filled with water; the oil displaced this water, taking its place. With the passage of time, the water and oil seeped through the bedrock until they met an impermeable rock.

Oil Exploration and Discovery

Locating oil reservoirs is generally a long and complicated task carried out in the following phases:

1. Geological reconnaissance of materials prone to oil storage.
2. Comparative studies with other oil-producing basins.
3. Search for geological traps where pockets of oil may exist.
4. Geophysical prospecting, consisting of a series of measurements and tests to detect changes in the reservoir relative to the surrounding area.
5. Drilling (Sondeos): Drilling the land to reach the reservoir.

Petroleum Refining and Distillation

Crude oil is a dark, sticky liquid that contains hundreds of different compounds, mainly hydrocarbons. Its composition varies according to its origin. As produced from wells, crude oil has very few applications. Once extracted, it must be subjected to a refining process.

In the refinery, crude oil is separated into different hydrocarbon fractions or groups that have different boiling points. The separation takes place in a fractional distillation column or fractionating tower, by introducing crude oil heated to 350°C at its base.

After boiling, the oil vapor rises, and the various fractions cool and condense according to their boiling points at different heights. In refineries, besides distillation, cracking and reforming processes are generally conducted, transforming heavy fractions (less in demand) into light fractions (greater in demand).

Transportation and Essential Uses of Crude Oil

Transportation Methods

Oil is transported to refineries via pipelines if transportation is by land, and by transport tankers when it is by sea.

Essential Uses of Petroleum

Oil is not only used as a fuel; it is also an essential raw material for manufacturing synthetic fibers and plastic materials. From the fractional distillation of petroleum, liquid fuels are obtained which serve as an artificial energy source in:

• Industry and homes.
• Transportation.
• Generating thermal electricity (power plants utilize the calorific value of the direct combustion of coal, fuel oil, etc.).

Internal combustion engines in vehicles exploit the explosive qualities of a mixture of air and gasoline.