An In-Depth Look At The Different Types of Crude OilFebruary 17, 2014
Casual discussions of crude oil often times make it seem as if there is only one type of crude oil for all uses. However, crude oil is actually recovered in a number of different physical and molecular states. It exists as light, medium, or heavy crude, and it may be dubbed "sweet" or "sour." These various classifications affect all aspects of the crude oil’s recovery, delivery and final use from its origin upstream, transportation through the midstream phase, and to the end user downstream. Different types of crude oil have different end usage, require various refinement techniques, and ultimately yield different quality products.
Classification Systems for Crude OilThe petroleum industry typically classifies crude oil based on the following three ways: Geographic Location - The geographic location of the oil field where the oil is recovered is commonly used to classify it. Thus crude oil might be called West Texas Intermediate, Brent Blend, or Dubai-Oman. API Gravity - API gravity refers to a density scale developed and used by the American Petroleum Institute (API). API Gravity is an inverse measure of the density of petroleum and the density of water. If the crude oil has an API greater than 10 it will float on water and is thus lighter than water. If the crude oil has an API lower than 10 it will sink in water due to being heavier. Sulfur Content - The third way crude oil is commonly classified is based on its sulfur content. If the crude contains relatively little sulfur then it is called "sweet." If it contains a large amount of sulfur then it is called "sour."
Types of Crude By API GravityWhen crude oil is classified based on its API gravity it is divided into one of the following four classifications:
- Light - Light crude oil has an API gravity of 31.1 °API or higher.
- Medium - Medium crude oil has an API gravity that ranges between 22.3 °API and 31.1 °API.
- Heavy - Heavy crude oil has an API gravity that ranges between 22.2 °API and 10 °API.
- Extra Heavy (Bitumen) - Extra heavy crude oil has an API gravity that is lower than 10 °API. Extra heavy crude oil is also commonly called “bitumen.”