Crude Specifications

API or Heaviness

  • The American Petroleum Institute gravity, or API gravity, is a measure of how heavy or light a petroleum liquid is compared to water. If its API gravity is greater than 10, it is lighter and floats on water; if less than 10, it is heavier and sinks. API gravity is thus an inverse measure of the relative density of a petroleum liquid and the density of water, but it is used to compare the relative densities of petroleum liquids.
  • The higher the number, the lighter the crude grade, thus Crude oil may be considered light if it has low density or heavy if it has high density

Sulphur Level

  • Crude oils that contain appreciable quantities of hydrogen sulfide or other reactive sulfur compounds are called "sour." Those with less sulfur are called "sweet."


  • Acidic crude oils are grades of crude oil that contain substantial amounts of naphthenic acids (NAs) or other acids. They are also called high-TAN crudes after the most common measure of acidity, the Total Acid Number (TAN). Crude oils with as little as 0.5 mg KOH/g acid or petroleum fractions greater than about 1.0 mg KOH/g oil usually qualify as a high acid crude or oil.

Natural Gas Condensates

  • Liquids that are separated from natural gas are refered to as Natural Gas Condensates
  • Natural-gas condensate is a low-density mixture of hydrocarbon liquids that are present as gaseous components in the raw natural gas produced from many natural gas fields


  1. Processing Acidic Crude Oils

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