Figure 5

Variation in concentrations of selected representative non-hydrocarbons in oil samples collected at the core outlet during the core flood experiment. Concentration data has been normalised to values obtained for the original (input) oil (see Table 1). Note that phenols (as exemplified here by p-cresol) show much stronger depletion than carbazoles. The first oil was eluted from the core after ca. 120 ml of oil had been injected.