Where Does Oil Come From?
All of the petroleum, or oil, we get from oil wells was formed from the remains of plants that lived and died in the shallow seas that covered much of the earth millions of years ago.
Over the centuries, rock-forming processes in the earth’s crust covered the plant remains with layers of rock. Droplets of oil—and also coal and gas—were all that remained of the ancient plant life.
Ages later, man would drill deep wells to reach the valuable oil. Most of our oil is at least a mile deep in the ground; a lot of it is more than two or three miles down.
Oil is usually found in underground areas called reservoirs. Scientists and engineers explore a chosen area by studying rock samples from the earth. Measurements are taken, and, if the site seems promising, drilling begins.
Above the hole, a structure called a ‘derrick’ is built to house the tools and pipes going into the well. When finished, the drilled well brings a steady flow of oil to the surface.