The separation of crude oil into petroleum products begins by boiling it in a distillation tower, where constituent hydrocarbons are separated into layers based on the temperatures at which they boil.

An overview of crude oil, including its constituent hydrocarbons and refinement outputs

The mixture is primarily composed of molecules of carbon and hydrogen atoms bonded into a variety of shapes and lengths, giving each different chemical properties, such as boiling points. Refining can remove elemental impurities—such as sulfur—after hydrocarbons are separated, ensuring the resulting products can be used effectively in other machines, such as car engines.

To use the various chemicals in crude oil, they must often be cracked—broken down into smaller molecules—to make their processing easier in everyday machines.

View the 45 gallons of refined products created from each 42-gallon barrel of crude oil

More than 85% is refined into fuels, such as gasoline and diesel, while about 10% is converted into raw materials for plastics, synthetic rubbers, and other essential products, such as lubricants. Because the majority of these products are less dense than the starting crude oil and additional inputs are introduced during the refining process, there is a processing gain of three gallons.

Crude oil is the type of oil used to create fuel like gasoline, heating oil, and more

Technically speaking, crude oil is unrefined petroleum. This article dives into the different ways it’s categorized (by density, sulfur content, and origin), and how the combinations of these types of oil are used.

The ins and outs of oil refining

The oil industry is broken up into the upstream, midstream, and downstream segments, and oil refining is part of the latter. “Downstream” refers to companies like Standard Oil that are converting crude oil into a finished product.

How crude oil is split across oil markets based on geographic origin

Brent, West Texas Intermediate, and Dubai are the three crude oil classes and differ in terms of typical refinery uses, density, sulfur content, and suitability for financial benchmarking. Brent, which originates in the North Sea, is traders' go-to benchmark, in part, because it is easily shipped and politically stable, and used to price most of the crude sold internationally.

A look at types of crude oil, distinguished by properties like heaviness and sweetness

API gravity is a unit that describes how heavy or light a crude oil sample is based on its density, with higher values indicating lighter, more valuable oil that requires less processing. The sweetness of crude oil refers to the amount of sulfur it contains, where sour crude oil requires more extensive treatment to remove the more abundant sulfur and sweeten it.

View a sample of objects surprisingly derived from crude oil, including chewing gum and lipstick

Crude oil processing produces a variety of fuels and the building blocks for plastics, but it also distills out the hydrocarbons used to make aspirin, Teflon, vinyl, crayons, candles, Tupperware, roofing shingles, asphalt pavement, hair dye, anesthetics, food-grade lubricants, polyester, synthetic rubber, and resins for items like dentures.

Despite the misconception that it comes from dinosaurs, crude oil forms when microorganisms, such as algae and plankton, are subjected to high pressure and high temperature while buried under layers of sediment.

See where the 100 million barrels of crude oil the world consumes daily end up.

The industrial methods for recovering helium, including filters and cryogenic separation

Membranes with microscopic pores of varying sizes can be used to selectively filter out components of natural gas, including helium, which can then be concentrated. Because helium requires the lowest temperature of all elements to condense into a liquid, extracted natural gas can also be cooled until only helium remains as a gas.

The boiling temperature of water decreases with increasing elevation because the molecules need less energy to overcome the lower atmospheric pressure associated with thinner air.

Demystifying the claim that crude oil is inorganically created and a renewable resource

The abiogenic petroleum theory holds that fossil fuels originate in Earth's mantle and are constantly replenished, rather than formed by microorganisms over millions of years. While inorganic chemical processes can produce simple hydrocarbons, the range of complex molecules found in crude oil suggests an origin from a diverse set of organisms. Isotope analyses of these molecules also support the model that they originated from living things that preferentially take up certain isotopes over others.

How Standard Oil created Chevron and ExxonMobil

Standard Oil was eventually ordered to separate into 34 different entities, and over the following years, those 34 companies merged into what is now called the “Big Four” in the oil industry.

The US exported more crude oil and petroleum products than it imported in 2025

In fact, the US has been exporting more oil and petroleum products than it imports since August 2021. Petroleum and petroleum product exports totaled about 10.7 million barrels per day, whereas imports totaled about 7.9 million barrels per day.

Many plastic products are molded from melted pellets called nurdles, which are made from ethylene and propylene extracted from crude oil.

How disruptions in oil markets can drive up the price of everyday goods

Most types of plastic are made from polymers derived from chemicals produced by the processing and refining of crude oil and natural gas. Spikes in the cost of either fossil fuel raise the cost of wrappings, tubs, and other plastic containers for products.

The price of crude oil accounts for roughly half of the price displayed at the gas pump

The properties of helium, which has the lowest boiling point of any element

The colorless, odorless, mainly unreactive element condenses from a gas into a liquid at -268.928 degrees Celsius (-452.07 degrees Fahrenheit)—near the lowest theoretically possible temperature—allowing it to serve as a liquid coolant in machines without the risk of causing damage as a solid.

At 0.01 degrees Celsius (32.02 degrees Fahrenheit) and about 0.6% of Earth's surface pressure, water simultaneously exists as a solid, liquid, and a gas.

The winding journey from Standard Oil to the modern oil industry

Standard Oil’s impact on the business world can be clearly seen today in oil giants like Exxon and Chevron. But the journey from the Rockefellers’ trust to the modern firms was a windy road. After the Supreme Court ordered Standard Oil’s break up, the first step saw it separate into many state-based companies like Standard Oil of California and the Ohio Oil Company. Visualize it here.

Learn about unconventional ways to clean up crude oil, including using moss and chickens

Studies show that microorganisms in chicken manure can break down the hydrocarbons in crude oil without producing toxic by-products. Scientists have also explored avoiding the environmental risks of chemical dispersants and synthetic adsorbents by using human hair and peat moss to adsorb crude oil, which can be taken up by their cuticles and porous structures, respectively.

Understanding why the US can't use its own crude oil and depends on global markets

Before advancements in fracking technology made lighter shale oil readily available, US refineries had been built and optimized for decades to process heavier oil from other countries with high profitability. Despite being able to refine lighter oil, US oil companies can operate with better margins by exporting it to other nations whose refineries are optimized for it and importing heavier oil, for which the US has the infrastructure.

The US shipped nearly 4 billion barrels of oil abroad in 2024

More than half of the US’s oil is exported as the country produces mainly light, sweet crude but has many refineries that handle heavy, sour types.

View a breakdown of worldwide oil production since 1900, mostly led by the US

When analyzing the production of crude oil, shale oil, oil sands, and condensates since the start of the 20th century, Saudi Arabia produced more crude oil only in 1977, from 1979 to 1981, and from 1991 to 2016. Nations such as Iraq and the United Arab Emirates produced much smaller quantities than both Saudi Arabia and the US.

A guide to crude oil and natural gas extraction, from rig site preparation to land restoration

Requirements for traffic plans, access roads, and noise barriers vary by state and local laws, but once the rig site is prepared, the rig is assembled and digs a well that is then encased in steel and cement to protect groundwater reservoirs. After drilling and testing the extraction pipe, fracking fluid is injected into the rock to create cracks where crude oil resides, allowing it to be pumped out.

While major oil spills result from accidental pipeline ruptures or damage to transportation vessels or rigs, as much as half the oil that reaches coastlines has naturally leaked from the seafloor.

Oil and natural gas from fracking is considered unconventional

This method forcibly extracts fossil fuels from tightly packed rocks, where they form from organic matter that has undergone extreme heat and pressure. Conventional drilling, on the other hand, waits for the oil and gas to escape from shale and accumulate in more porous and permeable rocks, such as limestone.

How to create salad dressings with oil and water solutions that don't separate into layers

Such dressings, even when whisked together, often break within a few minutes, resulting in bites that are either harsh or oily. Small amounts of emulsifiers, such as mustard or mayonnaise, can stabilize and suspend oil droplets in water for longer periods because they possess both hydrophilic (water-loving) and hydrophobic (water-repelling) ends.

The story of the first commercial US oil well and why crude oil is measured in barrels

The 1859 oil discovery in Titusville, Pennsylvania, sparked a boom in oil exploration and production to meet the demand for kerosene lamp fuel. Because the 42-gallon barrel was a readily available container already in use for shipping fish, butter, wine, and other goods, it was adopted by the Petroleum Producers Association in 1872 and by both the US Geological Survey and the US Bureau of Mines in 1882.

Oil markets are seeing higher costs and lower prices amid tech breakthroughs

Experts say oil demand has not yet reached its peak. Recent technological breakthroughs in the oil industry include advances in drilling and extraction, as well as subsurface technologies.

The cleanup of oil and other chemical spills involves a combination of methods tailored to different settings, including vacuuming, dispersing absorbent materials, chemicals, or biological agents, and localized burning.

Some geothermal power plants make electricity using a secondary fluid

Direct dry-steam systems pull underground steam into a turbine-generator system, while flash and double-flash cycle systems spray extracted liquid water into a low-pressure tank, causing it to rapidly vaporize—"flash"—before moving to the turbine. Binary cycle systems use the extracted steam and water to flash a second fluid that easily boils, which then drives the turbine.

Watch a server submerged in a fluid continue to run and stay cool by boiling the liquid away.

The recorded history of crude oil use dates back about 5,000 years, with the Babylonians using it to waterproof their boats and as mortar in the construction of structures.

How freeze-drying leaves food with less than 4% of its original water content

In specialized equipment, foods are brought down to temperatures below freezing before a vacuum pump removes the air from the container, lowering the pressure around the food and the boiling temperature of water. Heaters beneath the food slowly raise its temperature above the now-reduced boiling point, causing the water to go from a frozen to a gaseous state.

OPEC often intervenes to influence the price of oil

This guide explains how investing in oil works with in-depth explanations of each of the forces that control oil’s price. Oil is unique as a commodity in part because of OPEC’s role in regulating its price.

Heat pumps use an easily boilable chemical to regulate temperature

In air conditioners, warm air is pulled from a home to turn a refrigerant into a gas, which is then compressed, raising its temperature. The gas naturally releases this energy to the comparatively cooler environment when exposed, then expands and is reused in the system. Heaters run in reverse, with the refrigerant picking up energy from the comparatively warmer environment.

The drastically different seat tiers on airplanes are a prime example of 'price segmentation,' which is key to keeping airlines profitable.

Trace the rise of oil: from early drilling to today’s global power

This animated map video vividly illustrates how petroleum shaped global politics and industry—from 18th-century uses and 19th-century drilling booms in North America to today’s OPEC strategies, shale revolution, and geopolitical oil influence.

Desalination involves costly, energy-intensive methods for producing freshwater

Thermal desalination heats saltwater to produce steam, and reverse osmosis forces saltwater through a membrane that only allows water through. In both cases, freshwater is collected and remineralized for consumption, while wastewater brine is often returned to the ocean, where it may harm marine organisms.

Explaining the Leidenfrost effect, where water can hover and move against gravity

Water droplets can glide across surfaces whose temperatures are well above water's boiling point. This heat instantly vaporizes the bottom of the droplet, creating a layer of steam that the rest of the droplet rides and bounces upon. This can be seen when sprinkling water on skillets to determine if the surface is hot enough to cook on.

A breakdown of Earth's atmospheric layers, including why it can get colder or hotter with altitude

Gases in the troposphere—the atmosphere's lowest layer—cool with increasing height as they get farther from the thermal energy emitted by Earth's warm surface. In the next layer—the stratosphere—ozone is increasingly heated by the sun's ultraviolet radiation with height. Because cooler air sinks and hotter air rises, the cooler troposphere and hotter stratosphere form a natural boundary keeping Earth's weather in the lowest layer.

Water vapor is used to manage heat in high-end smartphones

While smartphones have traditionally been cooled using a highly conductive plate that dissipates heat from the chip, vapor chambers offer a higher heat-removal capacity. This technology has been utilized in laptops for decades to absorb heat by cycling a fluid between liquid and gaseous phases.

Explore a timeline of US dependence on crude oil from 1850 to 2023

Oil dependence began with the rise of oil as a commodity, followed by an era of geopolitical competition for the resource after World War II. The domestic fracking boom, which started around 2006, was driven by a desire to reduce the nation's dependence on international adversaries for energy.

Why have gas prices surged nearly 27% since the Iran war began?

Oil passing through the Strait of Hormuz makes up only about 7% of US crude imports. However, crude oil prices account for 51% of the cost of a gallon of gas in the US. US refiners pay the Brent crude futures price, even for domestic drilling.

Explaining concentrate and how concentrate-derived juice differs from its source

Developed to reduce the volume of goods—thus lowering storage and shipping costs—the concentration process uses pressure and heat to remove water, pulp, and skin from fruits. Concentrates provide significant flavor, sugar, and calories to foods in small quantities, but do not retain most of the fiber, vitamins, and other nutrients from the source fruit.

The world's longest-running science experiment aims to prove if pitch is a liquid

Having run continuously since 1927, the pitch drop experiment is designed to show that the seemingly solid derivative of tar is a liquid by watching to see it drip through a tunnel. From 1930 to 2025, the substance has only produced nine drops, such that its viscosity—resistance to flow—is about two million times more than honey.

Watch how seed cotton is collected and processed into cotton fibers, feed for livestock, and cooking oil.

Although vinegar was first discovered when wine was left to sour after exposure to air, the fermentation of different base ingredients contributes to the variety of vinegars seen today.