Influence of the Structure of Heavy Oil Disperse System on its Rheological Properties Under Steam-Heat Treatment Conditions

© 2017, Springer Science+Business Media, LLC, part of Springer Nature. The distinctive features of the structure and composition of hydrocarbon disperse systems in various types of heavy oils after steam-heat treatment, including use of low-boiling hydrocarbons, are determined. Methodological approaches are developed to determine the stability of heavy hydrocarbon resources as a function of composition and structure of the hydrocarbon disperse systems. Based on theoretical concepts of oil disperse systems, the composition of the latter is characterized quantitatively. A notable feature of low-viscosity oils is greater affinity of the components of the solvate shell and the dispersion medium. As a result, the dispersion medium participates in cross-linking of the oil disperse system significantly, which leads to a decrease in the dispersivity of the system and in its viscosity

Low-Temperature Oxidation of Heavy Oil in Carbonate Medium Using Cobalt (III) Acetylacetonate as Catalyst

© 2017, Springer Science+Business Media, LLC, part of Springer Nature. The results of laboratory experiments on modeling of heavy oil oxidation processes in an air-oxygen environment using cobalt (III) acetylacetonate as catalyst at temperatures and pressures typical of thermal production methods are presented. It is established that the high-molecular components of the heavy oil are degraded in the air-oxygen environment at temperatures above 250°C in the presence of the catalyst with formation of low-boiling hydrocarbon fractions and oxygen-bearing compounds, and this reduces the density and viscosity of the transformed oil. In addition, the products obtained in the experiments show an increased asphaltene content and the presence of finely disperse carbonaceous substances, indicating the occurrence not only of cracking, but also of condensation processes. The experimental data indicate the main directions of the reactions and transformations of heavy oil hydrocarbon components in the studied systems, which provides the possibility of using cobalt acetylacetonate as a catalyst in the in-situ low-temperature oxidation of heavy oil in carbonate reservoirs

EXTREMELY SMALL INCISIONS 25G IN SURGERY OF CONGENITAL CATARACTS COMPLICATED WITH MICROPHTHALMIA IN CHILDREN OF THE FIRST YEAR OF LIFE

Purpose. Aim of the work was a comparative study of the results of cataract surgery with IOL implantation in children with congenital cataracts, complicated with microphthalmia operated on in the age from 1 to 12 months using the 20G and 25G technology. Materials and methods. A comparative study of cataract extraction with IOL implantation and pars plana removal of posterior capsule with a limited anterior vitrectomy were performed in 54 children with congenital cataracts, complicated with microphthalmia operated on in the age from 1 to 12 months (79 eyes). The children were divided into two subgroups: in the first group after the IOL implantation the pars plana removal of posterior capsule with a limited anterior vitrectomy 20G was carried in 26 children (41 eyes), and in the second group – with an access through pars plana using extremely small incisions 25G (28 patients, 38 eyes). Results. In the first subgroup in the early postoperative follow-up the complication rate was higher due to a more frequent occurrence of hyphema and a development of inflammatory reaction, the difference is statistically significant (34.1 and 10.5% respectively, p<0.01). Conclusions. The use of ultra-small accesses 25G, for the posterior casulectomy with the anterior vitrectomy after IOL implantation allows to reduce the quantity of early postoperative complications after removal of congenital cataracts, complicated with microphthalmia.><0,01).Conclusions. The use of ultra-small accesses 25G, for the posterior casulectomy with the anterior vitrectomy after IOL implantation allows to reduce the quantity of early postoperative complications after removal of congenital cataracts, complicated with microphthalmia

Femtolaser Systems in Congenital Cataract Surgery in Children

Purpose. To study the features and results of femtolaser use in congenital cataract surgery in children. Patients and Methods. 35 children (37 eyes) with congenital cataracts aged from 12 months to 14 years (5.38 ± 6.3 years) were examined and surgical treated. The first stage of the operation included femtolaser execution of the anterior capsulorhexis (femtosecond laser Victus™ (Technolas Perfect Vision/Baush&Lomb, Germany). The second stage was the flap of the anterior capsule removal, the performance of hydrodissection, aspiration of lens masses, intracapsular implantation of the IOL. Results. In case of femtolaser capsulotomy, its diameter increased. It depended on the child age and the state of the anterior lens capsule. The obtained disc diameter of the anterior capsule in almost all eyes was significantly less than planned, due to its high elasticity in children. Conclusion. The use of a femtosecond laser in children with congenital cataracts, especially in infants, increase the effectiveness of visual rehabilitation. When conducting an anterior femtolaser capsulotomy in children with congenital cataract, it is necessary to take into account an increase in the diameter of the anterior capsulotomy, depending on child age and the condition of the anterior lens capsule. The first stage of surgery under local anesthesia in older children requires an individual approach

Geothermal Transformatiom of Organic Matter in Supercritical Water with Magnetite and Coal Particles

© 2017, Springer Science+Business Media New York.The mechanisms of conversion of high-viscosity oil in supercritical water in the presence of finely dispersed coal and magnetite are clarified. The experiments were conducted in a closed reactor under conditions that ensure transition of the aqueous phase to a supercritical fluid. The general mechanisms of change in component and group compositions are explained, and the rheological properties of the original and transformed oil are studied. Degradation of the high-molecular part of the feedstock with formation of light hydrocarbons that were absent in the original oil is confirmed, and the significant decrease in viscosity of the transformed oil relative to the original is proved

Geothermal Transformatiom of Organic Matter in Supercritical Water with Magnetite and Coal Particles

© 2017, Springer Science+Business Media New York.The mechanisms of conversion of high-viscosity oil in supercritical water in the presence of finely dispersed coal and magnetite are clarified. The experiments were conducted in a closed reactor under conditions that ensure transition of the aqueous phase to a supercritical fluid. The general mechanisms of change in component and group compositions are explained, and the rheological properties of the original and transformed oil are studied. Degradation of the high-molecular part of the feedstock with formation of light hydrocarbons that were absent in the original oil is confirmed, and the significant decrease in viscosity of the transformed oil relative to the original is proved

Composition and Property Changes in Oil Dispersions After Hydrothermal Treatment of Rock-Forming Minerals with Hydrocarbon Solvents

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Group and elemental compositions and structures of hydrocarbon dispersions in super-viscous oil resulting from steam and heat exposure at 140-190°C and 3-6 atm in the presence of hexane and benzene are established using simplified models of terrigenous and carbonate reservoirs. A relationship between the composition and structure of the oil dispersions after steam-heat action and a temperature dependence of viscosity are established. Solvate shells of increased thickness around complex structural unit nuclei and a greater proportion of dispersion medium are distinctive features of the low-viscosity displaced oil. Studies show that the dispersion medium impacts greatly the formation and properties of the oil dispersion. Benzene in the displacing agent decreases the degree of dispersion of the system and the viscosity of the displaced oil

Influence of the Structure of Heavy Oil Disperse System on its Rheological Properties Under Steam-Heat Treatment Conditions

© 2017, Springer Science+Business Media, LLC, part of Springer Nature. The distinctive features of the structure and composition of hydrocarbon disperse systems in various types of heavy oils after steam-heat treatment, including use of low-boiling hydrocarbons, are determined. Methodological approaches are developed to determine the stability of heavy hydrocarbon resources as a function of composition and structure of the hydrocarbon disperse systems. Based on theoretical concepts of oil disperse systems, the composition of the latter is characterized quantitatively. A notable feature of low-viscosity oils is greater affinity of the components of the solvate shell and the dispersion medium. As a result, the dispersion medium participates in cross-linking of the oil disperse system significantly, which leads to a decrease in the dispersivity of the system and in its viscosity

Characteristics of Distillation Residues from Liquid Pyrolysis Products

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Heavy ends obtained from thermomechanical distillation of water-tar emulsions of liquid pyrolysis products from a broad fraction of light hydrocarbons and the ethane fraction were studied. Their physicochemical parameters were determined. Various processing schemes for heavy ends were proposed. It was found that the properties of used diesel fuel (UDF) were closest to those of the products. The high densities of the products limited the use of heavy ends as UDF. This problem was solved by proposing a shift of the UDF and vat residue ratio to 4:1 to produce commercial UDF blends

Characteristics of Distillation Residues from Liquid Pyrolysis Products

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Heavy ends obtained from thermomechanical distillation of water-tar emulsions of liquid pyrolysis products from a broad fraction of light hydrocarbons and the ethane fraction were studied. Their physicochemical parameters were determined. Various processing schemes for heavy ends were proposed. It was found that the properties of used diesel fuel (UDF) were closest to those of the products. The high densities of the products limited the use of heavy ends as UDF. This problem was solved by proposing a shift of the UDF and vat residue ratio to 4:1 to produce commercial UDF blends