a. The amount of liquid petroleum remaining in a formation at the end of a
specified production process. AGI
b. Liquid or semi-liquid products obtained as residues from the
distillation of petroleum. They contain the asphaltic hydrocarbons.
Residual oils are also known as asphaltum oil, liquid asphalt, black oil,
petroleum tailings, and residuum. CCD, 2
Dictionary of Mining, Mineral, and Related Terms