A new method for the determination of the hydrocarbon groups in oil : saturates, aromatics, resins and asphaltenes (SARA)

A newly developed method for determining fractions of saturates, aromatics, resins and asphaltenes in crude oil and oil products was described. The separation process used for saturates and aromatics is column elution, which can be quantified by gas chromatography with flame ionization detection (GC/FID). Precipitation of the oil in excess pentane is used to gravimetrically measure asphaltenes. The removal of resins from the pentane-soluble oil fraction is accomplished by column elution and weight determination. Using this new method, a total of twenty crude oils and oil products were analyzed. They included a variety of products, ranging from very light refined products such as diesel, to bitumens such as dried Orimulsion-400, and artificially weathered fractions. For all the oils, the results obtained proved to be consistent, repeatable, and reproducible. 10 refs., 1 tab