Iron oxide nanoparticles impact on improving reservoir rock minerals catalytic effect on heavy oil aquathermolysis

Abstract

The past decade has seen a renewed importance in developing heavy oil reserves due to the rapid raise in energy resources’ demand. The next decade is likely to witness a considerable rise in extracting these resources by thermally enhanced oil recovery methods. However, many hypotheses regarding the influence of reservoir mineral components on aquathermolysis reactions appear to be disputable. This paper outlines a new approach to model the aquathermolysis of Aschalcha’s reservoir rock heavy oil in the presence and absence of iron oxide nanoparticles combined with hydrogen donor in water steam atmosphere at 200, 250, and 300 °C using different physical and chemical methods. X-ray powder diffraction (XRD) and scanning electron microscopy (SEM) have showed adsorbed spherical magnetite (Fe3O4) nanoparticles with less than 100 nm size on the studied rock minerals in hydrothermal conditions. Moreover, SARA (Saturates, Aromatics, Resins and Asphaltenes) analysis, gas analysis, and gas chromatography–mass spectrometry (GC–MS) have revealed that the obtained iron oxide nanoparticles exhibit their highest catalytic activity at 250 °C comparing to 200 and 300 °C respectively. What’s more, the obtained data have indicated a considerable decrease in resins (from 19.6 to 8.9 wt%) and asphaltenes compounds (from 5.1 to 1.5 wt%) in the presence of iron oxide nanoparticles comparing to the non-catalytic aquathermolysis of reservoir rock heavy oil. Contrary to resins and asphaltenes’ content, it has been found that saturates’ content increases significantly from 41.1% to 61.7% wt%. On another hand, the viscosity of the extracted oil has decreased almost 30 times and the gas proportion has doubled more than twice from 0.2 g to 0.43 g per 100 g of the reservoir rock sample. Interestingly, these results have been obtained in the presence of iron oxide nanoparticles at 250 °C, meanwhile, the same results have been found for the non-catalytic experiments at 300 °C. These findings confirm the significant contribution (synergistic effect) of iron oxide nanoparticles to stimulate the catalytic activity of the reservoir rock minerals. What’s more, the evidence from this study suggests that the presence of iron oxide nanoparticles in hydrothermal conditions at higher temperatures leads to the formation and adsorption of heavy coke-like carbenes, carboides, needle coke as well as carbon nanotubes of 100 nm size on the surface of the reservoir rock heavy oil as confirmed by thermal analysis (TG-DSC), SEM, and drop shape analysis (DSA) data.