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Heavy crude is a type of crude oil that is thicker, denser, and more viscous than conventional light crude oil.  It has a higher molecular weight and contains a larger proportion of heavier hydrocarbons, making it more difficult and costly to extract, transport, and refine.  Heavy crude typically has a higher density and lower API gravity (American Petroleum Institute gravity), which is a measure of how light or heavy a petroleum liquid is compared to water.  A lower API gravity means the oil is denser and heavier.

Heavy crude isn’t defined by a single molecule or a specific "molecule number," it’s a complex mixture of hydrocarbons with varying molecular weights, typically characterized by high viscosity and density compared to light crude oil.  Heavy crude generally contains hydrocarbons with carbon chains ranging from C20 to C50 or more, often including large amounts of asphaltenes, resins, and other heavy compounds.  The exact composition depends on the source of the oil.

Heavy crude is a significant energy resource, as it is abundant, especially in places where light crude reserves are declining.  However, due to its challenges, production is often more expensive and has a larger environmental impact.

Key Points about Heavy Crude

High Viscosity  -  Heavy crude is much thicker than light oil, meaning it flows slowly.  It often requires heating or dilution with lighter oils to move through pipelines.
High Sulfur and Metal Content  -  Heavy crude usually contains more sulfur, heavy metals, and impurities than lighter oils, making refining more complex.
Lower API Gravity  -  Heavy crude typically have an API gravity of less than 20°, while light oils have a higher API, generally above 30°.
Thermal and Chemical Extraction Methods  -  Due to its high viscosity, heavy crude often requires enhanced recovery methods like steam injection, solvents, or other thermal processes to reduce viscosity and improve flow during extraction.
Found in Specific Regions  -  Major heavy crude reserves are located in regions like Canada (particularly Alberta’s oil sands), Venezuela’s Orinoco Belt, and parts of the Middle East.
 
 

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