An oil well is a general term for any boring through the Earth's surface that is designed to find and acquire petroleum oil hydrocarbons. Usually some natural gas is produced along with the oil. A well that is designed to produce mainly or only gas may be termed a gas well.

According to George E. Totten, the earliest known oil wells were drilled in China in 347 CE. They had depths of up to about 800 feet (240 m) and were drilled using bits attached to bamboo poles. The oil was burned to evaporate brine and produce salt. By the 10th century, extensive bamboo pipelines connected oil wells with salt springs. The ancient records of China and Japan are said to contain many allusions to the use of natural gas for lighting and heating. Petroleum was known as burning water in Japan in the 7th century.

The Middle East's petroleum industry was established by the 8th century, when the streets of the newly constructed Baghdad were paved with tar, derived from petroleum that became accessible from natural fields in the region.^{[citation needed]} According to Kasem Ajram, petroleum was distilled by the Persian alchemist Muhammad ibn Zakarīya Rāzi (Rhazes) in the 9th century, producing chemicals such as kerosene in the alembic (al-ambiq),^{[verification needed]} and which was mainly used for kerosene lamps.Arab and Persian chemists also distilled crude oil in order to produce flammable products for military purposes. Through Islamic Spain, distillation became available in Western Europe by the 12th century.

An oil is any substance that is liquid at ambient temperatures and does not mix with water but may mix with other oils and organic solvents. This general definition includes vegetable oils, volatile essential oils, petrochemical oils, and synthetic oils.

First attested in English 1176, the word oil comes from Old French "oile", from Latin "oleum", which in turn comes from the Greek "ἔλαιον" (elaion), "olive oil, oil" and that from "ἐλαία" (elaia), "olive tree". The earliest attested form of the word is the Mycenaean Greek e-ra-wo, written in Linear B syllabic script.

Organic oils are produced in remarkable diversity by plants, animals, and other organisms through natural metabolic processes. Lipid is the scientific term for the fatty acids, steroids and similar chemicals often found in the oils produced by living things, while oil refers to an overall mixture of chemicals. Organic oils may also contain chemicals other than lipids, including proteins, waxes and alkaloids.

Lipids can be classified by the way that they are made by an organism, their chemical structure and their limited solubility in water compared to oils. They have a high carbon and hydrogen content and are considerably lacking in oxygen compared to other organic compounds and minerals; they tend to be relatively nonpolar molecules, but may include both polar and nonpolar regions as in the case of phospholipids and steroids.

Paul Neal "Red" Adair (June 18, 1915 – August 7, 2004) was an American oil well firefighter. He became world notable as an innovator in the highly specialized and extremely hazardous profession of extinguishing and capping blazing, erupting oil well blowouts, both land-based and offshore.

Adair was born in Houston, Texas, and attended Reagan High School. He began fighting oil well fires after returning from serving in a bomb disposal unit during World War II. He started his career working for Myron Kinley, the "original" blowout/oil firefighting pioneer. He founded Red Adair Co., Inc., in 1959, and over the course of his career battled more than 2,000 land and offshore oil well, natural gas well, and similar spectacular fires. Adair gained global attention in 1962, when he tackled a fire at the Gassi Touil gas field in the Algerian Sahara nicknamed the Devil's Cigarette Lighter, a 450-foot (137 m) pillar of flame that burned from 12:00 PM November 13, 1961 to 9:30 AM on April 28, 1962. In December 1968, Adair sealed a large gas leak at an Australian gas and oil platform off Victoria's south-east coast.