Downhole Upgrading of Orinoco Basin Extra-Heavy Crude Oil Using Hydrogen Donors under Steam Injection Conditions. Effect of the Presence of Iron Nanocatalysts

摘要

An extra-heavy crude oil underground upgrading concept and laboratory experiments are presented which involve the addition of a hydrogen donor (tetralin) to an Orinoco Basin extra-heavy crude oil under steam injection conditions (280–315 °C and residence times of at least 24-h). Three iron-containing nanocatalysts (20 nm, 60 nm and 90 nm) were used and the results showed increases of up to 8° in API gravity, 26% desulfurization and 27% reduction in the asphaltene content of the upgraded product in comparison to the control reaction using inert sand. The iron nanocatalysts were characterized by SEM, XPS, EDAX, and Mössbauer spectroscopy before and after the upgrading reactions. The results indicated the presence of hematite (Fe₂O₃) as the predominant iron phase. The data showed that the catalysts were deactivating by particle sintering (~20% increase in particle size) and also by carbon deposition. Probable mechanisms of reactions are proposed.