Kazan Federal University

The viscosity of crude oil is an important phys. property that largely determines the fluidity of oil and its ability to seep through porous media such as geol. rock.Predicting crude oil viscosity requires the development of reliable models that can reproduce viscosity over a wide range of temperatures and pressures.Such viscosity models must operate with a set of phys. characteristics that are sufficient to describe the viscosity of an extremely complex multi-phase and multi-component system such as crude oil.The present work considers empirical data on the temperature dependence of the viscosity of crude oil samples from various fields in Russia, China, Saudi Arabia, Nigeria, Kuwait and the North Sea.For the first time, within the reduced temperature concept and using the universal scaling viscosity model, the viscosity of crude oil can be accurately determined over a wide temperature range: from low temperatures corresponding to the amorphous state to relatively high temperatures, at which all oil fractions appear as melts.A novel methodol. for determining the glass transition temperature and the activation energy of viscous flow of crude oil is proposed.A relationship between the parameters of the universal scaling model for viscosity, the API gravity, the fragility index, the glass transition temperature and the activation energy of viscous has been established for the first time.It is shown that the accuracy of the results of the universal scaling model significantly exceeds the accuracy of known empirical equations, including those developed directly to describe the viscosity of petroleum products.

In order to improve the heavy oil quality, the electromagnetic (EM) heating method with the addition of metal catalysts has been considered.Oil-soluble catalyst precursors, which consist of a ligand and a metal, prevent their clumping and precipitation by dispersing nanoparticles in oil.Unfortunately, no research was found to investigate the effect of adding this type of catalyst on increasing the efficiency of EM heating and optimizing the recovery of heavy oil.The aim of this paper was to propose nickel-adipic (NOSC) as an oil-soluble catalyst precursor to increase the efficiency of EM heating.A set of 2.45 GHz industrial magnetrons was used as the microwave radiation source with the addition of 1 wt% NOSC (containing 0.39 % Ni) at time intervals of 3, 6 and 9 min.At 9 min, asphaltene and resin content decreased by 21.91 % and 40.07 %, and saturate and aromatic content increased by 11.13 % and 41.3 %, resp.In addition, the viscosity also showed a decrease of about 60 %.Elemental anal. showed 11 %, 13 % and 20 % reduction of sulfur after 3, 6 and 9 min, resp.According to the results of GC-MS, the content of n-C₂₆-C₃₂ compared to the control sample (ACO) was reduced by 2 times in 6 min.In addition, observing the increase in the content of naphthalenes and light alkylbenzenes in aromatic compounds was a proof of the effectiveness of the NOSC catalytic system in heavy oil upgrading.This paper presents a promising approach to enhance the performance of EM heating in heavy crude oil recovery.

The present investigation explores the catalytic efficiency of iron ligated catalysts derived from tall and sunflower oils in the in-situ combustion process for heavy oil oxidationAddressing the challenge of enhancing heavy oil recovery in an environmentally friendly and economically viable manner, this study evaluates the potential of these bio-originated catalysts to improve the oxidation rates of heavy oil components, focusing on the high temperature oxidation region critical for controlling the combustion front.Through a comprehensive exptl. approach involving physicochem. anal. such as IR spectroscopy, X-ray powder diffraction, thermal anal. (TG/DSC), kinetic modeling and thermodn. study, the present research revealed that the iron bio-originated ligands significantly enhance the oxidation process.The catalyst derived from sunflower oil exhibited a superior performance, demonstrating a more pronounced reduction in the activation energy required for heavy oil high temperature oxidation across a wide range of conversions.Specifically, the sunflower oil-based ligand catalyst showed lower activation energies 105.5 kJ/mol for high-temperature oxidation reactions comparing to tall oil-based catalyst (136.4 kJ/mol) and heavy oil (149.1 kJ/mol), highlighting its effectiveness in facilitating and stabilizing the combustion front.Post-oxidation anal. revealed that the Fe-SFO catalyst maintained a more uniform and finer particle size distribution compared to the Fe-TO catalyst.The Fe-SFO catalyst predominantly had particle sizes in the range of 20 to 120 nm, suggesting that its smaller particle size could provide a larger surface area for reaction and enhance the catalyst′s ability to interact with reactants.These findings underline the catalytic capabilities of bio-originated ligands in improving heavy oil recovery processes, suggesting that the adoption of such sustainable catalysts could lead to greener and more efficient chem. processes in the energy sector.