Crude oil reservoirs have their own unique characteristics and properties. The market value of an individual stream can be determined by grading the oil on two scales:
1. API Gravity
The oil’s density to water which ranges from “light” to “heavy”. Light is the preferred density.
The sulphur content of the oil. Less than 0.5% sulphur and the oil is “sweet” while greater than 0.5% indicates the oil is “sour”.
The market prefers sweet crude (e.g. North Europe and Central U.S.) to sour crude (e.g. Middle East) as it requires less processing to remove impurities.