How is oil produced or retrieved?

Oil is produced or retrieved through a process called drilling, where a well is drilled into underground reservoirs containing crude oil. Once a well reaches the oil reservoir, pressure may cause the oil to flow to the surface naturally, or pumps may be used to extract it. After extraction, the crude oil is transported for refining, where it is processed into various petroleum products. Enhanced recovery techniques, such as injecting water or gas into the reservoir, may also be employed to increase oil production.