Petroleum is formed by the slow alteration of organic remains over time.
It consists of a mixture of liquid hydrocarbon compounds and varies widely in composition, color, density, and viscosity. This liquid, after distillation, yields a range of combustible fuels, petrochemicals, and lubricants. Petroleum is usually classified according to the predominance of paraffin or asphaltic compounds and, accordingly, is said to have a paraffin base, an intermediate base, or an asphalt base. Uses Petroleum is used principally as a source of fuel and lubricating oils. Only when these supplies are restricted or threatened does the average person begin to realize their importance.