Characterization of asphaltenes and resins from problematic Mexican crude oils

Asphaltenes and resins have been separated from four mexican oils suffering from the deposition of asphaltenic material during recovery operations. A SARA separation of the oils was performed and the resins and asphaltenes fu rther analyzed. Characterization methods employed were FTIR, elemental comp osition both of CHNSO, and trace metals and molecular weight determination using size exclusion chromatography. NMR techniques were applied to two asp haltene samples, The overall scope of the work was to get a better understa nding of the nature of the asphaltene stability at a molecular level in the se problematic oils. Separation of resin in two fractions indicates that th ere is no long alkyl chains in these as given by FTIR, which may be the cau se of the lack of stability along with the large difference in bubble point and reservoir pressure.