Petroleum is a complex chemical compound made up of solid, liquid, and gaseous parts. It is formed from hydrocarbons like carbon and hydrogen, along with small amounts of other elements. Crude oil is a black or dark brown liquid found in sedimentary rock deposits in areas that were once underwater. Pipelines are an important method for transporting large quantities of oil over land and water due to their efficiency and ability to reduce costs compared to other transportation methods. Pipelines, tank farms where oil is stored, and oil tankers of various sizes are all critical infrastructure used to move crude oil and refined products around the world.