Petroleum

Petroleum is a naturally occurring, yellowish-black liquid chemical mixture. It is primarily composed of hydrocarbons, which are molecules made of carbon and hydrogen atoms. The term petroleum refers to both the unprocessed crude oil found in the ground and the various refined products made from it. This substance is a fossil fuel, meaning it was created from the remains of ancient life. It plays a massive role in global industry, providing the energy and raw materials that power much of modern civilization.

The formation of petroleum is a process that takes millions of years. It begins with the anaerobic decay of organic materials, such as plankton and algae. These tiny organisms die and sink to the bottom of ancient water bodies. Over vast amounts of time, they are buried under layers of sediment. Because this decay happens without oxygen, the organic matter transforms into oil. Most of the world's oil deposits formed during the Mesozoic era, which accounts for about 70% of reserves. The Cenozoic era produced 20%, while the Paleozoic era contributed only 10%.

To use petroleum, humans must first extract it from geological formations. Conventional reserves are typically recovered by drilling into a petroleum reservoir. Before drilling, experts conduct a study of structural geology and analyze the sedimentary basin. They must also characterize the reservoir to understand how the oil is stored. Some oil is found in unconventional reserves, such as oil sands or oil shale. These require different methods of extraction, such as fracking, to reach the hydrocarbons.

Once extracted, the crude oil must undergo refining to become useful. The most common method is distillation, which is a process used to separate the mixture into different parts. Through distillation, the various components of the oil are separated based on their properties. This creates a wide range of products for direct use or manufacturing. Common fuels include gasoline, diesel, kerosene, and jet fuel. Other products include bitumen, paraffin wax, and lubricants. Petroleum is also used to create reagents for plastics, solvents, textiles, and even pharmaceuticals.

Humans have utilized petroleum in various forms since ancient times. Over 4,300 years ago, the Sumerians used bitumen to build boats. In ancient China, records show that oil was used as fuel as early as the 4th century BCE. By 347 CE, the Chinese were producing oil from wells drilled with bamboo. In the 19th century, the industry became more organized and industrial. In 1853, Ignacy Łukasiewicz discovered how to distill kerosene and opened the first industrial refinery in Poland.

Later, in 1859, Edwin Drake drilled the first successful oil well in Pennsylvania, sparking a global boom.

While petroleum is vital for the economy, it has significant environmental impacts. It is a non-renewable resource, meaning it cannot be replaced once it is used. The extraction, refining, and burning of petroleum release large quantities of greenhouse gases. These gases act as a counter to natural carbon sinks and contribute to anthropogenic climate change. Additionally, petroleum use can cause direct environmental damage through oil spills. Secondary pollution of air and water sources is also a common concern.

The control of petroleum has shaped world history and politics. Many countries, known as petrostates, gained immense economic and international influence during the late 20th century. Because of its importance, access to oil has fueled many geopolitical conflicts and resource wars. However, the future of petroleum is changing. Experts estimate that production may reach peak oil before 2035. As the world focuses on climate change mitigation, there is a growing transition toward renewable energy and electrification.