How were oil and natural gas formed?
Most scientists believe that oil and natural gas was formed about 300 million years ago during the Carboniferous period of the Paleozoic era. Petroleum began to form as plant and animal remains decayed in sediments at the bottoms of oceans, lakes and streams. Over time, massive amounts of pressure and high temperatures converted the organic matter into oil and gas. Sometimes these oil and gas accumulation became trapped in rock formations. Today, oil companies study these rock formations in their search for oil and natural gas. When they find a formation that is likely to contain petroleum, the company drills a well.
