ASPHALTENIC CRUDE-OIL CHARACTERIZATION - AN EXPERIMENTAL INVESTIGATION OF THE EFFECT OF RESINS ON THE STABILITY OF ASPHALTENES

High performance liquid chromatography (HPLC) and Thin Layer Chromatog raphic (TLC) latroscan were used to characterize an asphaltenic stock tank oil (STO) from the North Sea. The whole STO was separated into sa turates, aromatics, polars 1 (resins 1), polars 2 (resins 2) and aspha ltene fractions. The separated resins (1) and the more polar resins (2 ), also termed asphaltene peptizing agents, were further characterized by HPLC in terms of their neutral, basic, pyrrolic and acidic compone nts. Resins (1) and resins (2) were mixed in different proportions wit h whole (original) STO; the resulting mixtures were tested for asphalt ene onsets of precipitation due to n-C5 injection at 25 degrees C and 690 kPa. Results of these tests are presented and the observed trends are explained in terms of resins characters and/or major constituents.