Sour Crude
Sour crude is a type of crude oil known for its relatively high sulfur content. The presence of sulfur makes oil more difficult and costly to refine, causing sour crude to be viewed as a less desirable form of crude oil. Sour crude products require additional processing to break down hydrocarbon compounds and remove various contaminants.
Crude oil is defined as “sour” if its sulfur content exceeds 0.5%, or if it does not meet the required thresholds for hydrogen sulfide and carbon dioxide levels.
In order to prepare sour crude for sale on commodities markets, oil refineries must use a process known as cracking to separate the dozens of hydrocarbon compounds contained in the oil into separate chemical units. The refineries must also eliminate various contaminants in order to produce saleable products.
Sweet Crude
Sweet crude refers to crude oil that is extracted that is found to contain very low amounts of sulfur. It is considered a valuable and efficient source of crude oil due to the fact that sulfur lowers the yield of various refined petroleum products such as gasoline, diesel fuel, and even plastics. When combined with low density, sweet crude is a highly sought after type of oil which commands a high price, known as light sweet crude.
This distinction between sour and sweet crude is important because it affects the cost of refining the oil. In turn, this makes the more costly sour crude less efficient as a source of energy production, decreasing its demand from commodity investors. In an effort to reduce their total processing costs, sour crude producers often seek to refine sour crude into heavy oil products such as diesel and fuel oil
