The photo is sourced from rscf.ru
One of the main methods for extracting heavy oil is the injection of superheated steam, which, when it turns into water, heats the oil formation, making the oil more mobile. To increase the energy efficiency of this oil production method, catalysts are introduced into the formation along with steam, ensuring the destruction of the heaviest components of oil: resins and asphaltenes. This improves oil recovery from the formation, also making the oil extracted from the subsoil easier to transport and process.
The scientists from Kazan Federal University have proposed using acetic acid salts (acetates) with transition metals along with steam treatment. From these compounds, particles of sulfides of the corresponding transition metals emerge in the oil formation, serving as an active form of the catalyst that affects the chemical bonds between carbon and sulfur in resins and asphaltenes.
First, the authors simulated standard steam treatment of heavy oil samples in a lab reactor, i.e., an autoclave. This approach proved to reduce the viscosity of oil by 39%. The researchers then added acetates of various metals – lead, magnesium, sodium, zinc, copper and nickel – into the autoclave and compared the properties of oil that had undergone this combined (steam plus catalyst) treatment with the results of a previous experiment where only steam was used. Copper and nickel acetates combined with the impact of steam managed to reduce the viscosity of the original oil by 58%, exceeding the parameters of purification by steam alone. This is due to the fact that the catalyst accelerated the breaking of chemical bonds in long molecules of resins and asphaltenes.
An analysis of the chemical composition of oil before and after thermal catalytic treatment showed that under the action of steam the share of heavy compounds dropped from 38% to 36%, whereas with the addition of nickel acetate it decreased from 38% to 24%. In the latter case, the content of light hydrocarbons and aromatic compounds rose from 62% to 76%. Taken together, these factors provided a 58% reduction in viscosity.
“We have demonstrated for the first time that metal acetates can be used for steam thermal technologies in heavy oil extraction. These low-cost and safe compounds will help improve the energy efficiency of the existing technology. In the future, we plan to conduct tests in a real oil-bearing formation to prove the possibility of using the proposed approach in practice,” Firdavs Aliev, leader of the study and candidate of technical sciences, is quoted as saying by the Russian Science Foundation.
