Sweet vs Sour Crude Oil
Sweet crude oil is considered “sweet” if it contains less than 0.5% sulfur. In comparison, sour crude oil contains impurity sulfur levels larger than 0.5%.
Sweet crude oil contains small amounts of hydrogen sulfide and carbon dioxide and it is commonly used for processing into gasoline, kerosene, and high-quality diesel. Before sour crude oil can be refined into gasoline, impurities need to be removed, therefore increasing the cost of processing. This results in a higher-priced gasoline than that made from sweet crude oil. For this reason sour crude is usually processed into heavy oil such as diesel and fuel oil rather than gasoline to reduce processing costs.
The sweet light crude oil Western Texas Intermediate (WTI) is used as a benchmark in oil pricing.