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Oil and petroleum products explained  

How was crude oil formed?

Crude oil was formed from the remains of animals and plants (diatoms) that lived millions of years ago in a marine environment before the existence of dinosaurs. Over millions of years, the remains of these animals and plants were covered by layers of sand, silt, and rock. Heat and pressure from these layers turned the remains into what we now call crude oil. The word petroleum means rock oil or oil from the earth.

Three images, about Petroleum & Natural Gas Formation. Adapted from the National Energy Education Development Project. The first image is about the Ocean 300 to 400 million years ago. Tiny sea plants and animals died and were buried on the ocean floor. Over time, they were covered by layers of sand and silt. The second image is about the Ocean 50 to 100 million years ago. Over millions of years, the remains were buried deeper and deeper. The enormous heat and pressure turned them into oil and gas. The third image is about Oil & Gas Deposits. Today, we drill down through layers of sand, silt, and rock to reach the rock formations that contain oil and gas deposits.

Source: U.S. Energy Information Administration (public domain)

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Diatom image: Group of cleaned frustules

Diatoms magnified under a microscope.

Source: Image used by permission from Micrographia

Last updated: December 11, 2018