Hydrothermal upgrading and adsorption of a water-soluble nickel-based catalyst precursor in a porous media of carbonate oil-saturated rock

This study investigates the efficiency of a water-soluble nickel-based catalyst precursor in enhancing oil recovery through steam injection processes. Four filtration experiments were performed using a bulk formation model with initial oil saturation to simulate steam injection in a carbonate reservoir. The experiments focused on the effects of catalyst concentration, soaking time, and temperature on oil displacement efficiency. Results revealed that the highest oil recovery factor (displacement coefficient) of 36.3% was achieved with the injection of a commercial nickel sulfate-based catalyst, accompanied by an extended soaking time of 24 h. The displaced oil exhibited significantly reduced viscosity and a decreased content of heavy fractions, including resins and asphaltenes, indicating improved oil quality. Furthermore, the study underscored the critical influence of temperature on catalyst adsorption dynamics. Notably, adsorption increased with rising temperatures, with over 99% of the catalyst being adsorbed on the rock at temperatures exceeding 160 °C. Interestingly, at lower temperatures, adsorption was more pronounced on rock with residual oil saturation compared to that with extracted oil, suggesting that residual oil may facilitate better catalyst retention. These findings contribute to a deeper understanding of the interplay between steam injection parameters and catalytic efficiency in heavy oil recovery, offering insights that could enhance the design and optimization of thermal enhanced oil recovery (EOR) techniques.