Scientists have revealed the synergistic effect of nickel stearate and decalin on the kinetics of processes occurring during heavy oil production

Aquathermolysis catalysts and solvents that can produce hydrogen at elevated temperatures are promising agents for improving the efficiency of oil production using water vapor injection technologies.

The aquathermolysis process can reduce the viscosity of heavy crude oil and its sulfur content. In recent years, it has been used for industrial purposes to extract and partially refine heavy crude oil under reservoir conditions.

The combined use of in-situ catalysts and steam injection makes it possible to extract high-viscosity oil from a depth of up to 1 kilometer. And if the effective effect of nickel and decalin-based compounds for the oil industry is far from being a secret, the necessary kinetic model that would quantitatively reveal the synergistic effect of these additives has not been developed.

At the current stage of the study, the scientists combined the properties of the two reagents to optimize the technology. The synergistic effect was observed due to the use of nickel stearate as a catalyst precursor and decalin as a hydrogen donor. The scientific results are published in the Journal of Molecular Liquids.

“This study reliably shows that the use of the two additives increases the rate of reactions that produce lighter fractions, promoting the conversion of large macromolecules within the oil and preventing secondary cracking reactions of the former, which directly affect the properties of the oil,” says Research Associate of the Laboratory of In-Situ Combustion Alexis Cota Tirado.

As part of the work, a separate kinetic model for aquathermolysis of heavy oil from the Ashalchi field was developed. The error of the kinetic model did not exceed 5%.

“The results are crucial to gain a better understanding of the effect of hydrogen donor on the catalytic reaction mechanism. This is the first kinetic model developed that considers the synergistic effect of solvent and catalyst to increase the conversion of high molecular weight fractions in heavy oils,” says Research Associate of the same laboratory José Guillermo Félix Lugo.

The approach developed to estimate the kinetic parameters and analyze the results from a phenomenological point of view of chemical reactions is completely new. The proposed kinetic model accurately represents the main changes in reactions resulting from solvents under aquathermolysis conditions.

“As part of the Russian Science Foundation-funded project, we are developing and selecting optimal compositions that include not only catalytic systems, but also solvents capable of dehydrogenation processes in reservoir conditions under thermal influence. All this will increase the efficiency of heavy oil production and reduce the ecological load on the environment, as the use of chemical additives reduces the volume of steam injection, which will lead to lower emissions into the environment and reduce the consumption of fresh water for the development of hard-to-recover hydrocarbon fields,” shares project lead, Chair of the Department of Petroleum Engineering Mikhail Varfolomeev.

The methods used and the results obtained will provide a solid foundation for future research and technological initiatives aimed at increasing the productivity of facilities with large reserves of heavy oil, of which there are several tens of billions of tons in Russia.