Petroleum (crude oil) is a smelly, yellow-to-black gooey liquid and is usually found in underground areas called reservoirs. To locate a reservoir, geologists explore a selected area by studying rock samples from the earth. Measurements are taken, and, if the site seems promising, drilling begins. Above the drilling hole, a structure called a derrick is built to house the tools and pipes going into the well (see image on the left). An offshore platform is used when oil is drilled in a body of water (see image on the right). When finished, the drilled well will bring a steady flow of petroleum to the surface.
Interesting fact: In 1859, Edwin Drake drilled the first oil well near Titusville, Pennsylvania.
