API gravity is a measure comes from American Petroleum Institute 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.
This is not a brand new formula but very handy calculation to have. The important calculation for Petroleum Engineer.
API Gravity = ( 141.5 / Specific Gravity ) – 131.5
Specific Gravity = 141.5 / ( 131.5 + API )
Example: pure water at 60 deg F with a specific gravity of 1.0 would have an API gravity:
API Gravity = ( 141.5 / 1.0 ) – 131.5 = 10 deg API
The principle is low API Gravity is mean height density petroleum
Classification crude oil based on API degree
- Light Oil
Light oil is conventional oil with API gravity minimum 22° and viscosity less than 100 centipoise (cp), this type crude oil is can flow naturally no need to steam.
- Heavy Oil
Low density crude oil and viscous is normally have API gravity less than 22°
- Extra Heavy Oil
Extra Heavy oil normally heavier than heavy oil and also have API gravity less than 10°
- Oil Natural Bitumen ( Extra-Heavy Crude Oil )
Also called oil sands, oil bitumen shares the attributes of heavy oil but have more viscosity and also the viscosity is greater than 10.000 cp
See table bellow to crude oil classification based on API Degree
Find the link for API calculator spreadsheet bellow and also looks table bellow for API Chart
Thanks For reading API Degree To Specific Gravity Calculation
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