 Oil production is a vital component of our economy in Wyoming, and a significant impact upon our landscapes. But not all of the oil produced in Wyoming is the same. Different grades of oil from sweet to sour and heavy to light can be found in Wyoming. The Bighorn Basin has produced a tremendous amount of oil for our country, with over 2.9 billion barrels extracted since the early 1900s. Much of this oil is a heavy, sour grade of crude. When looking at a pump jack through the window of a car, most people figure oil is oil. But the different uses and value between sweet or sour and light or heavy crude are significant. The sour crude of the Bighorn Basin contains more sulfur than sweet crude, which changes the way the oil must be refined. Heavy oil is just that, heavier than light oil. The heavier chemical composition means that refining costs can be greater than sweet crude. Like our diverse natural landscapes, each of Wyoming's oil fields are unique. Next time you visit the Bighorn Basin or fill up at the pump, be sure to appreciate our great variety of oil resources. From the University of Wyoming Extension, I'm Barton Stam, exploring the nature of Wyoming.