Abstract
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.
Highlights
Downhole upgrading processes have several potential benefits in comparison to aboveround counterparts: Firstly, enhanced oil recovery can be obtained by accessing more difficult fluids with the potential increase of the volumetric production of wells
In our previous publications [3,4,5,6], we reported a concept that involves the addition of a hydrogen donor additive and, in the presence of steam, natural formation and methane, leads to extra-heavy crude oil upgrading at lab conditions [5,6]
These changes can be attributed to upgrading reactions occurring during the time needed to reach the distillation temperature to separate the tetralin, which was approximately 30–45 min
Summary
Downhole upgrading processes have several potential benefits in comparison to aboveround counterparts: Firstly, enhanced oil recovery can be obtained by accessing more difficult fluids with the potential increase of the volumetric production of wells. In our previous publications [3,4,5,6], we reported a concept that involves the addition of a hydrogen donor additive (tetralin or other distillate fractions having at least 40 wt.% naphthenic aromatic compounds) and, in the presence of steam, natural formation (catalyst) and methane (natural gas), leads to extra-heavy crude oil upgrading (from 9 to 14° API) at lab conditions [5,6] This concept could be coupled to a steam stimulation process with 70–80% hydrogen donor recycled [5,6]. In this work, three iron-containing nanocatalysts were evaluated and laboratory experiments will be presented that involve the addition of a hydrogen donor additive (tetralin) to an Orinoco Basin extra-heavy crude oil (Hamaca C.) under steam injection conditions
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