Some patterns of changes in the composition and properties of asphaltenes from the dispersed organic matter of various genetic types and from the oils of Western Siberia
L. S. BORISOVA
A. A. Trofimuk Institute of Petroleum Geology and Geophysics of the Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: asphaltenes, oils, genotype, organic matter, physicochemical methods, Western Siberia
Abstract
Using a complex of physical and physicochemical methods (spectroscopy in the visible region, IR, NMR, EPR spectrometry, X-ray diffraction, elemental analysis, Rock-Eval pyrolysis), some features of the composition and structure of asphaltenes in oils and dispersed organic matter in the rocks of Western Siberia were studied. The composition and properties of asphaltenes reflect changes in the oil genetic types, similar to those previously established during the study of the hydrocarbon part: from marine oils of the Latitudinal Ob region to continental oils of the northern regions. The geochemical patterns of changes in the composition and structure of asphaltenes of dispersed organic matter were discovered. Passing from the Volga stage of aquagenic origin up and down the section of Western Siberia, the signs of terrigenous type of organic matter appear in asphaltene structure: the atomic ratio of hydrogen to carbon decreases, the contribution from condensed aromatic fragments increases, and metal-porphyrin complexes are not detected.
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