PARAFFIN DEPOSITION IN OIL PRODUCTION. OIL COMPOSITION AND PARAFFIN INHIBITORS ACTIVITY

Several commercial paraffin inhibitors were evaluated with highly paraffinic crudes. Pour point depression was observed in some of the studied crudes in the presence of any product, while others showed insignificant changes in this parameter. Crudes characterization was achieved with physico-chemical analysis (pour point, cloud point and API gravity) and hydrocarbon analysis (thin layer chromatography with flame ionization detection, wax content, gel permeation chromatography and high temperature simulated distillation). A correlation between crude oil composition and paraffin inhibitors activity was found. The normal / cyclo+iso-paraffins ratio of the crudes that were not affected by the paraffin inhibitors was found higher compared to the others. The molecular weight distribution of the crudes which responded to modifiers, showed a bimodal character and a concentration of components with more than 24 carbon atoms lower than 39 % wt. On the other hand, the crudes insensitive to the action of the inhibitors displayed monomodal molecular weight distributions with larger contributions of heavy components (more than 52 % wt). Doping experiments supporting the former findings, permitted to asses the inefficiency of commercial paraffin inhibitors for crudes rich in C24+ alkanes.