An appropriate pattern recognition method has been designed to visually discriminate between crude oils belonging to different geographic origins. Each oil is represented by a circular profile that consists of parameter axes that radiate from the centre like spokes on a wheel. One objective of this approach is to provide an optimum set of axes that will best differentiate one circular profile from another. Several parameters were considered for evaluating the oils: photo-acoustic spectroscopy (PAS), carbon-13 nuclear magnetic resonance (13C NMR, for %CA = aromatic carbon content), high-performance liquid chromatography (HPLC, for unsaturated, aromatic, and polar compounds), initial boiling point (IBP), American Petroleum Institute (API) gravity, and ultraviolet–visible spectrophotometry (for λmax = maximum absorption wavelength and εmax = maximum molar absorptivity). By computerized statistical evaluation, the selected parameters are PAS and HPLC for unsaturated, aromatic, and polar compounds.