Oil Migration Study of the Western Slope,Jinhu Depressionof Subei Basin,Eastern China

Key words: 
• pyrrolic /
• nitrogen /
• compounds /
• dibenzofuran /
• dibenzothiophene /
• absolute quantitative analysLs /
• migration effect．

Abstract: Oil migration effect of the western slope, Jinhu Depression of Subei Basin, Eastern China is observed on the base of detailed work of investigating genetic mechanism and source rock of the petroleum. The methods of the study adopted include non hydrocarbon and absolute quantitative analysis of biomarkers and the other kind of the compounds in different fractions by co injection of standard compounds. The main method is emphasized on studying the migration fractionation effect of pyrrolic nitrogen compounds in the oil. The other two kind compounds' migration fractionation effect is also observed, which are dibenzofuran and dibenzothiophene series with the similar molecular structure as the pyrrolic nitrogen compounds. The result indicates that the pyrrolic nitrogen compound in the oil has apparent migration fractionation effects, which infer the oil migration direction of the area is form northeast to southwest, and the Shanghe Sag is the main source cooker of the oil. The migration fractionation effects could also be observed in the other two kind compound series dibenzofuran and dibenzothiophene bearing oxygen and sulfur heteroatom respectively, which make the compounds having strong polarity too. However, their fractionation effects are not apparent as the nitrogenic compound. The migration fractionation effects of the three compounds increase according to the order of dibenzoghiophene, dibenzofuran and nitrogen compounds, which infer the polarity of the three kind compounds increasing according to the order. It is probably the hetroatoms in the compounds determining the chemical characteristics of the compounds. The results also indicate that the absolute quantitative analysis is very useful in study petroleum migration, the migration fractionation effect could be observed from the abundance variation of some high molecular compounds, especially the heterocyclic compounds such as NSO' compounds metioned above.