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Abstract

This paper presents a method to correct the values of the mass fractions of saturates, aromatics, resins and asphaltenes (SARA analysis) of dead crudes by adding the dissolved gas to the saturated fraction of SARA analysis. This paper also shows the procedure to obtain the necessary equations to correct each fraction from the volumetric gas/crude ratio (Rs). Four hypothetical crudes were analyzed to calculate the different mass ratios. The SARA analysis of 27 Colombian crudes was performed and the incidence of dissolved gas was determined in the calculation of live crude SARA. The change in the saturated fraction was between 2 and 22% for Black Oil and between 14 and 74% for Volatile Crude Oil. Furthermore, a modification of the “Colloidal Instability CII Index” is presented, and the values obtained by this new methodology are compared to this index.