MODELING OF CRUDE OIL COMPONENT COMPOSITION FOR WESTERN SIBERIA OIL FIELDS

Abstract

The component composition of natural hydrocarbons in crude oil varies in a wide range for different fields. The results of the analysis of deep oil samples chromatographic research for some Western Siberia oil fields are presented. Significant heterogeneity of the composition presented by the are revealed. On the graphs of the dependence curves of the pseudo-component mole fractions concentration from their molecular weight single and double maxima were discovered. A modification of S.N. Whitson method of mathematical pre-diction of oil component composition was made. The developed technique by adjusting parameters is calibrated for some oil fields in Western Siberia. The molecular weight of the calculated (virtual) oils (light and heavy) remained unchanged in all calculated cases - M'C7 + = 160 g/mol; M'C7 + = 351 g/mol. The discrepancy between the calculated and experimental values zi from the molecular weight Mi for the examined oil fields did not exceed 5 %. The performed calculations showed that in different wells of the same oil field formation oil can have different proportions of light and heavy components with the same distribution parameters and the curvature of the three-parameter gamma distribution function. A mathematical model is developed that allows to predict the component composition of heavy components obtaining the calculated dependences of mole fractions of pseudo-components from their molecular weight.