Colors of oil , including deep red, golden yellow, dark green, black, maroon and clear. In short, oil is very rich in color, depending on the content of gums and asphaltenes in it, the higher the content, the darker the color.
Some wells in Dagang Oilfield in North China produce colorless oil, Karamay oil is brown to black; Daqing, Shengli and Yumen oil are black. Colorless oil is produced in California, Baku in the former Soviet Union, Romania, and Sumatra in Indonesia.
The formation of colorless petroleum may be related to the adsorption of colored colloids and asphaltenes by rocks during migration.
However, dark oil of varying degrees accounts for the majority, almost all over the world’s major oil and gas basins.