ABSTRACT
Crude oils represent mixtures of a large number of hydrocarbon components with many different physical and chemical characteristics. This chapter illustrates the most important properties of crude oils using assays from two US Strategic Petroleum Reserve blends: Bayou Choctaw Sour and West Hackberry Sweet. Bayou Choctaw Sour and West Hackberry Sweet are crude blends located in Louisiana in the Strategic Petroleum Reserve. Assays of whole crudes are carried out using atmospheric and vacuum distillation, which produce distillate fractions and residual bottoms similar to refining processes. The main elements in crude oil are carbon, hydrogen, sulfur, nitrogen, oxygen, and metals. Heavier crude oils typically have higher carbon residue than light crudes. The heavier and denser the crude oil, the higher its CH ratio; and similarly, for any cut, the heavier the boiling range fraction, the higher its CH ratio. Metallic compounds exist in all crude oils and can vary from a few parts per million to more than 1000 ppm.
