How was petroleum formed deep under the earth?

Further layers settled to the sea or lake bed, intense heat and pressure build up in the lower regions. This process caused the organic matter to change into petroleum. The word petroleum comes from (petra) for rocks and (elaion) for oil. That means oil trapped between rocks. read more

If abiogenic petroleum sources are indeed found to be abundant, it would mean Earth contains vast reserves of untapped petroleum and, since other rocky objects formed from the same raw material as Earth, that crude oil might exist on other planets or moons in the solar system, scientists say. Both processes for making petroleum likely require thousands of years. Even if Earth does contain far more oil than currently thought, it's inevitable that reserves will one day run out. read more

Coal, natural gas, and petroleum are all fossil fuels that formed under similar conditions. Today, petroleum is found in vast underground reservoirs where ancient seas were located. Petroleum reservoirs can be found beneath land or the ocean floor. Their crude oil is extracted with giant drilling machines. read more