Vol 54, No 1 (2018)

Pretreatment processes for stable gas condensates are examined to increase the yield of light fractions and to improve product quality at primary refineries. Effects of pretreatment with a constant magnetic field of a stable gas condensate in flow mode with filtration through titanium-fiber filters on the feedstock disperse phase and atmospheric-distillation product yield and quality are studied. It is shown that the yield of light fractions increases by 4-13 wt% after treatment with magnetic field of various strengths; by 7-16 wt% with subsequent filtration. The octane number of the gasoline cut increases by 4-10 points. The cooking capability of the residue decreases by 1.1-1.7 times depending on the gas-condensate pretreatment process. The system dispersion increases after treatment with the magnetic field, which has a positive effect on the atmospheric-distillation product yield and quality.

The influence of UV-irradiation by an XeCl excimer lamp on the physicochemical and catalytic properties of MFI-type high-silica zeolites modified by cobalt tungsto- and molybdobismuthates in the process of getting high-octane gosoline components is studied. It is show that the concentration of acidic centers can be increased by 76%; the arene yield, by 4-13 wt%; and the octane number of the products, by 2-3 points as compared with starting zeolite if cobalt tungstobismuthate heteropoly compound (1 wt%) is used as the modifier and the material is activated by UV-irradiation for 24 min. It is established that UV-irradiation of modified zeolites increases the concentration of acidic centers and decreases the adsorption capacity and specific surface area.

Biofuels, derived from renewable biological resource, are universally recognized as viable alternatives to fossils fuels foe powering automotive internal combustion engines. In this study, fuels blends with biofuels (methanol, butanol or ethanol) and pure ultra-low-sulfur oil were used in a turbocharged diesel engine to test its performance and exhaust emission compositions. It was found that addition of 2 wt. % methanol, butanol or ethanol to fuel blends reduced exhaust emissions on average by 4.15, 5.8, and 8.89%, respectively, when compared with ultra-low-sulfur diesel. The reason for the reduced emissions is absence of sulfur and sulfuric acid in the biofuel blends.

Esters were synthesized using synthetic petroleum acids and ethylene glycol. The esterification was carried out in various types of reactors in the presence of commercial Zeokar-600 catalyst. Physicochemical properties of the synthesized esters and of 5 and 10% compounds of these esters with the diesel fraction were determined. The esters obtained can be used as additives to diesel fuels to improve their performance properties.

Use of a combination of multistage hydrofracking and high-pressure air injection is proposed for developing low-permeability oil deposits of the Tyumen Suite (Upper Jurassic). An effective inert gaseous agent is formed during intrastratal transformation of the air due to oxidation of the oil. The oil autooxidation mechanism is studied. A weak dependence of the oxidation rate on the oil properties is observed.

The degree of water dissolution in oil affects the flow behavior of oil—water mixtures in reservoirs and pipes. A multiphase flash algorithm was used to calculate the solubility of water in oil containing asphaltenes at various temperatures and pressures. A cubic-plus-association equation of state was used to simulate the formation of H-bonds between water molecules and polar asphaltene molecules. Experimental water solubilities in four oil samples validated that the method assumptions were accurate. The results demonstrated that the average absolute deviation between the experimental and calculated mole fractions of water in oil was less than 0.04673 in the range 452-557 K. Also, this method could explain the smooth transition from solubilized water at high temperatures to emulsified water at lower temperatures.

The closure of artificial fractures is one of the most complicated problems in the development of unconventional oil and gas reservoirs. Aiming at modifying the current theoretical models, an analytical model of the contact process was proposed with due regard for elastoplastic deformation. The constructed model is based on Hertz’s elastic contact equations and can be used to interpolate an exponential function. A numerical analysis method was used to derive the equation of state to determine the rigidity and asperity of the alastoplastic phase for all the deformation phases. The correlation between average contact pressure and fracture closure of the entire rough surface was established using probability statistics. Compared with the classical models, this analytical model is easier to consruct and use. As the new model takes into account all the deformation phases, it describes the fracture surface contact behavior well with increasing normal stress. Comparison has shown that the results calculated by the developed model are in agreement with the finite-element-based Kogut-Etison (KE) model.

The feasibility of use of motor oils in engines as the base of flushing products is explored. A technological process is proposed for cleaning working dirty motor oil without draining it out from the engine crankcase and subsequent addition to it of agents that facilitate removal of deposits from the cylinder-piston group parts. It is shown that resin and asphaltene particles can be enlarged by using monoethanolamine and isopropanol as agents to sizes that are easily removable by cleaning agents integrated into the engine lubrication system. It is determined that subsequent addition of dimethyl sulfoxide blended with white spirit to cleaned motor oil used in the engine makes it possible to remove resins and tars from engine parts, raise compression, and reduce fuel consumption.

The deformation-strength (strength and plasticity) and dilatometric (contraction or volume shrinkage) properties of binary composites of solid edible paraffin wax P-1 with ceresins C-65, C-80, and C-85, waxes, and soft paraffin waxes are studied. Diagrams of property composition state are constructed. The functional dependencies of these properties on the content of modifying components in the composites with paraffin wax P-1 are established.

The physical mechanism of air-foam flooding that was proposed earlier by other authors was studied using NB-95 foaming agent as an example. The parameters for air-foam injection in the T9 block of SY oilfield were simulated numerically optimized using the STARS module of the CMG reservoir simulation software. The experimental results demonstrate that the optimal injection-volume-to-production ratio for air-foam flooding in the T9 block is 0.8-1; gas-to-liquid ratio, 0.8-1; foaming agent concentration, 0.5-0.75%; and injection slug, 0.18-0.22 of the pore volume. Experimental physical simulation shows that air-foam flooding can enhance oil recovery by 25.85% and can be used to develop a theory of oil displacement by air-foam flooding.

The acknowledgement on page 895 should read

This work was carried out with the financial state support of Russian Ministry of Education and Science (Specific Project Identifier RFMEF157717X0239; Contract No. 14.577.21.0239).