Geochemical Correlation of Petroleum

Abstract

Variations in the properties of petroleum as it exists in the reservoir or crude oil as stock-tank liquid are the consequence of one or more factors in its geologic history or mode of production. For any given objective, be it comparison in respect to origin as a tool in exploration or identification in pollution studies, use should be made of those properties which are most diagnostic for the correlation desired. For correlation with respect to origin, procedures suitable for gas or liquid-petroleum samples or combinations thereof have been developed. For gas or gas associated with oil, two procedures are used, one based on comparison of ratios of components of like physical and chemical properties in the range C1 through C10, and the second on carb n-isotopic composition of the individual C1 through C4 components. For crude oils a three-parameter procedure is used. It consists of (1) determination of the carbon isotopic compositions of the topped crude and the saturate, aromatic, and asphaltic fractions; (2) the n-paraffin distribution; and (3) the odd-even predominance (OEP).