Definition - What does Heavy Oil mean?
Heavy oil is used to refer to the crude oil that has high viscosity and high specific gravity level as compared to light crude oil. It is also known as heavy crude oil or extra heavy crude oil. Due to its high viscosity, heavy oil cannot flow easily to production wells, not unless favorable conditions are provided using artificial means. Apart from its high density and API gravity level, heavy oil also contains heavy molecular arrangement. Any petroleum oil that has gravity below 20° is classified as heavy oil. Due to the bulky composition, the extraction and production of heavy crude oil is a challenging task.
Petropedia explains Heavy Oil
In the petroleum industry, any liquid petroleum that is high in viscosity, has an API gravity less than 20° and cannot flow easily is referred to as heavy crude oil or simply, heavy oil. Since the extracted oil can be of different molecular composition and viscosity, any oil that exhibits the properties as that of the heavy oil is classified as heavy crude oil; while crude oil that has API gravity less than 10° is classified as extra heavy crude oil. Most of the crude oil when extracted is usually thick and it is lightened only by allowing it to go through refining processes.