Effect of Mineralogy on the Physicochemical Properties of a Heavy Crude Oil in Hybrid Steam Injection Technologies Using 1H NMR

Abstract

The present study focused on the experimental evaluation of the effect of mineralogy in oil upgrading under two hybrid steam injection technologies. The tests were carried out in a batch reactor, using iron naphthenate as the catalyst and flue gas. The physical changes of the crude were evaluated by density and viscosity measurements, while the variations of the crude molecular structure were quantified using nuclear magnetic resonance (1H NMR) spectroscopy. The results showed that for the technique with catalyst, the scenario with the highest proportion of clay increased the API gravity by 27% and reduced the crude viscosity by 39%. The additional upgrading was the result of mineral presence with a contribution of 13% due to H2 production and the inhibition of polymerization. Additionally, the presence of the mineral phase with flue gas in the system reverses some of the subprocesses of the aquathermolysis reactions that favor the improvement of the crude. For this hybrid technique, the best scenario was achieved in the absence of the mineral phase with an increase of 10% in API gravity and a reduction of 41% in viscosity concerning the base crude as a product of the flue gas mechanisms. The changes in the physical properties can be correlated with the modifications in the chemical structure of the crude oil. These changes were a result of dealkylation, hydrogenation, and condensation reactions, evidenced by the variation of average molecular parameters, obtained by 1H NMR, such as the aromaticity factor and the number of substituted rings.

Combining Steam and Flue Gas as a Strategy to Support Energy Efficiency: A Comprehensive Review of the Associated Mechanisms

“…In a study by Mecón 60 et al, 2022, through tests in a batch-type microreactor with steam-flue gas-crude and different mineralogy, it was evident that the presence of certain minerals and the CO 2 of the flue gas promote polymerization reactions, a chemical subprocess associated with aquathermolysis, where by the action of temperature generates the breaking of complex chains and the unstable free radicals intertwine, forming more complex and heavier compounds, thus increasing the initial viscosity of the crude oil. 61 …”