Method for calculating the individual hydrocarbon composition from the accumulated fractional composition of oil and condensate samples

Abstract

The composition of oils is the main source of information that enables the evaluation and modeling of their physical, thermal and chemical properties (including their critical properties) across a wide range of state parameters. The more comprehensively the composition of oils is analyzed, the more precise information is provided for calculations and problem-solving in the field of oilfield mechanics and related areas, such as the extraction, preparation, transportation, and processing of oils and their fractions. The principal constituents of oils are hydrocarbons. Oils contain hydrocarbons of three homologous series: paraffins, naphthenes and aromas. In oils, there may be hydrocarbons of a mixed composition containing both naphthenic and aromatic rings. In addition to hydrocarbons, oils also contain oxygen, sulfur, nitrogen and other constituents. These compounds are the primary elements of asphaltene-resinous substances (ARS) found in oil. They are characterized by high relative densities (often exceeding 1 g/cm3), dark coloration, and relative chemical instability when exposed to elevated temperatures, oxygen, adsorbents, etc. The composition of asphaltene-resinous substances encompasses a wide range of substances. The validity of the proposed technique is justified by the observation that the data of molecular weight, Watson characteristic factor, and experimental density calculated from molar compositions should align on the same surface with a high degree of correlation. In addition, the experimental and calculated values, in terms of molecular composition, of molecular weights should lie on a straight line passing through the origin of coordinates with a slope coefficient equal to unity and exhibit high degree of correlation.