Search

During waterflooding of a multilayer oil field there is a constant deterioration of the structure and composition of residual reserves due to geological and technological reasons. The largest share of residual reserves is localized in pillars, which arise from uneven development of the production facility and are undrained or poorly drained zones. The results of a quantitative assessment of the distribution of residual oil reserves in the Middle and Upper Devonian deposits of the Romashkinskoe oil field of the Republic of Tatarstan are presented. A retrospective method is proposed to identify reserves by analyzing and summarizing historical exploration data and the long history of reservoir development, and a calculation algorithm is proposed to quantify them. It has been established that residual oil reserves are localized in rows of dividing and injection wells, as well as in the central rows of producing wells in a three-line drive, in abandoned and piezometric wells, in the areas adjacent to the zones of reservoir confluence, pinch-out, oil-bearing contours, distribution of reservoirs with deteriorated porosity and permeability properties. Depending on geological conditions, algorithms for selecting geological and technical measures to include localized reserves in development and forecasting production profiles were proposed. According to the proposed method, residual recoverable reserves were identified and a number of wells were recommended for experimental works on their additional recovery: in well 16 (hereinafter in the text, conventional well numbers are used) after isolation of overlying high-water-cut formations, the additional perforation was carried out and oil flow was obtained. Additional perforation in well 6 resulted in oil recovery during development as well. Thus, the developed approaches to identifying residual recoverable reserves and patterns of their spatial distribution can be recommended in other multilayer oil fields with a long history of development.

The paper presents the results of experimental evaluation of oil displacement efficiency by flue gas of a thermal power plant, compared to water, for a carbonate reservoir in the Ural-Volga region. The experiments were performed under two different injection schemes using an original laboratory complex for coreflood studies, with recombined reservoir oil, model of formation water, reservoir core material, and under reservoir thermobaric conditions. It has been confirmed that due to the prevailing nitrogen content and low values of reservoir pressure and temperature, flue gas is ineffective as an independent displacement agent either for injection from the beginning of reservoir development or as a tertiary method after waterflooding. Taking into account the relevance of synergy between increasing oil recovery and sequestration of industrial emissions, evaluation of flue gas injection as part of water-gas mixtures (SWAG) is recommended.

Relevance. Recently, ESG (Environment, Social, Governance) principles have been given an important role in the agenda of oil and gas companies – this is an actively developing global trend in the modern business environment. One of its key aspects is a responsible attitude to the environment, increasing the priority of solving environmental problems arising from the extraction of hydrocarbons. A significant environmental problem is, in particular, pollution of freshwater horizons during oil production due to their poor-quality insulation during well cementing. At the same time, in the space of the well behind the casing, there is a flow of borehole fluid to freshwater horizons, which has a negative impact on the environmental situation in this region. In this regard, monitoring the technical condition of wells crossing freshwater horizons is an important and urgent task. Object. An operational well drilled through freshwater horizon, in which geophysical studies are carried out by the method of active thermometry – local heating of the casing section is carried out and the dynamics of the temperature field in it is studied. Aim. To identify qualitative patterns and obtain quantitative estimates of the effect of the fluid flow in the space behind the casing (column space) on the temperature field in the casing. Methods. Numerical mathematical modeling of thermal and hydrodynamic processes in a well using the software package Ansys Fluent (ANSYS Academic Research CFD license, agreement with Bashkir State University dated 06/15/2020). Results. The authors have studied the influence of a plane-parallel horizontal fluid flow of the freshwater horizon on the azimuthal temperature distribution of the casing string during induction heating. It is shown that in the case of leakiness of the cement ring in the interval of the freshwater horizon, an inhomogeneity of the azimuthal temperature distribution of the column is observed, reaching a value of few more K. The authors carried out the simulation of induction heating in the well with liquid column flow to the interval of the freshwater horizon. It is shown that the sign indicating the overflow is the occurrence of a temperature disturbance area vertically above the induction heating interval with a length of more than 1 m. In general, the results of the performed studies show the informativeness of the active thermometry method in relation to the diagnosis of the technical condition of wells drilled through freshwater horizons.

The functional dependence of thermograms in producing wells has been studied in order to determine the initial temperature distribution along the wellbore. Information about the initial thermal field makes it possible to ensure the reliability of solving the problem of determining the operating intervals in production wells. In this paper, we propose a method for isolating the linear dependence on the thermogram profile in the intervals of the absence of fluid movement (in the sump of a working and along the trunk of an idle well) by constructing a special function – the vronskian. In this paper, it is established that the use of the vronskian can be used to restore the geothermal distribution, as well as to obtain the value of the geothermal gradient and temperature in the analysis of the thermogram. To discuss the possibilities of the proposed method, three cases were used: a model and two thermograms in a real field study. The first option considered is a synthetic thermogram with a quasi-stationary mode of operation of the well. In the second and third cases, the results of thermometric studies in the well with a short-term inflow from the reservoir with the same and different lithological structure of the intervals in the sump are presented. The obtained algorithm can be used to isolate the intervals of linear dependence during express processing of registered thermograms in order to obtain quantitative parameters of the operation of the borehole-formation system.

The article considers mathematical models of two spheroidal spiral-frame emitters, built on the basis of a general approach involving the use of an integral representation electromagnetic field. The internal problem of electrodynamics is reduced to a system of Fredholm integral equations of the 1st kind. The resulting system was solved by the method of moments with piecewise constant basis functions and delta functions as test functions. In this case, the local linearization of the generating conductors of the structures under consideration was carried out. The dependences of current distributions, input resistance, and radiation characteristics of structures on frequency have been studied. It is shown that standing, traveling, and mixed current waves can exist in the structures under consideration. The current regime is determined by the wave sizes and the geometry of the structures and determines the behavior of the wave resistance in the frequency range. Despite the similar geometry, the characteristics of the considered structures have certain differences.

Growing chronic diseases among city dwellers, rapidly spreading epidemics due to increased mobility lifestyles, and the consequences of forced isolation in response to the recent global pandemic command the attention of researchers in various fields of knowledge to the modeling of a salutogenic habitat in modern cities. The aim of this study is to identify the principles of architecture that contributes to human health and general well-being. In particular, the study seeks to develop a theoretical model of salutogenic architecture; review domestic and international theoretical studies and design developments devoted to various aspects of salutogenic architecture and of salutogenesis; and analyze techniques of form generation, functional planning and environmental organization of architecture, especially residential complexes and urban clusters that meet the criteria of salutogenesis. The following principles have been identified: balance, symbiosis and hybridization, variation and integration, transformation, stimulation and discharge, meaningfulness and manifestation, controllability and autonomy. The identified principles and techniques allow the design process and search for architectural form for residential urban clusters to be appropriately adjusted to achieve a salutogenic built environment.

Generalized approximate weak greedy algorithms (gAWGAs) were introduced by Galatenko and Livshits as a generalization of approximate weak greedy algorithms, which, in turn, generalize weak greedy algorithm and thus pure greedy algorithm. We consider a narrower case of gAWGA in which only a sequence of absolute errors {ξn}n=1∞{\left\{{\xi }_{n}\right\}}_{n=1}^{\infty } is nonzero. In this case sufficient condition for a convergence of a gAWGA expansion to an expanded element obtained by Galatenko and Livshits can be written as ∑n=1∞ξn2

Decreasing negative impact of industrial emissions to the atmosphere and prolonging fossil fuel usage period are urgent issues of fuel and energy sector. In view of this problem, injection of flue gases into oil fields to increase oil recovery may be considered as environmentally safe and economically rational way for beneficial use of greenhouse gas emissions. To effectively displace oil with flue gases it is important to consider many factors: influence of composition of the flue gases and oil, miscibility conditions, injection regimes, etc. Flue gases, a product of fuel combustion in air, can be produced as a result of oil self-ignition when air is injected into a reservoir with light oil (thermal gas method). Flue gases from natural gas, fuel oil or coal combustion in power plants or other processes that burn fossil fuels can also be used for injection into the reservoir. This paper presents an analysis of the world laboratory and industrial experience in studying efficiency of oil displacement using flue gases. Conclusions are presented about optimal criteria for implementation of this process and directions for further research.

The paper presents the results of assessing the effectiveness of a complex feed additive based on halloysite for experimental T-2, afla- and zearalenone toxicosis of white rats in terms of survival, changes in clinical condition, enzyme status of blood serum and spleen ultrastructure. The results presented in the article confirmed the danger of the combined effects of mycotoxins on the body of white rats. The presence of mycotoxins in the feed led to the death of 30.0% of rats with a change in the clinical condition of the surviving animals, a significant increase in the serum levels of aminotransferases, alkaline phosphatase, lactate dehydrogenase, creatine kinase and gamma-glutamyltransferase, as well as changes in the ultrastructure of the spleen. A normalizing effect of a food additive based on halloysite on the studied parameters in experimental combined mycotoxicosis was noted, which was manifested by 100% survival of rats, less pronounced changes in the enzyme status and a protective effect on the ultrastructure of the spleen. This makes it promising for further comprehensive research on productive animal species with the prospect of implementation in animal husbandry as an effective means of preventing combined mycotoxicoses.

This study investigated the combined effects of deltamethrin and T-2 toxin on animals, utilizing bentonite as a prophylactic agent. The research was conducted on white rats, which were orally administered the toxins for 20 consecutive days. Subsequently, clinical, hematological, and biochemical parameters were examined to assess the impact of the toxins on the animals. Based on research results, it has been established that the combined effect of deltamethrin and T-2 toxin with repeated administration is characterized by more severe clinical, hematological and biochemical changes than with separate exposure to toxicants. Accompanied by a decrease in the number of leukocytes, erythrocytes and hemoglobin, a decrease in total protein, glucose and cholinesterase activity. Adding bentonite to the feed as a prophylactic agent at a dose of 2% of the diet has a preventive effect in case of combined poisoning with deltamethrin and T- 2 toxin, and helps to normalize the clinical, hematological and biochemical parameters of animals.

The influence of the composition of the nutrient medium on the yield of biomass and the biosynthesis of agglutinins of the mold fungus strain Rhizoctonia solani RS was studied. At the first stage of research, the agglutinin-producing micromycete strain was grown on liquid nutrient media (potato-glucose (PG), Chapek, Sabouraud) at a temperature of 28°C for 8 days. At the next stage of research, the composition of the culture medium was modified in order to select sources of nitrogen (NH4NO3, (NH4)2SO4, NaNO3, arginine, tryptophan, asparagine, threonine, peptone) and carbon (sucrose, glucose, starch) nutrition. Cultivation of the Rh. solani RS on a liquid PG medium, containing glucose in an amount of 20.0 g/l led to a maximum yield of fungal biomass of 23.58 ± 1.30 g/l and the production of its agglutinins (titer 16384). The studied micromycete strain was characterized by the ability to actively use the amino acids threonine or asparagine when added to the above nutrient medium in an amount of 0.1 mg/ml. At the same time, the hemagglutination activity of the micromycete agglutinins increased twofold (titer 32768) compared to the activity of agglutinins on the PG medium without the addition of amino acids (titer 16384).

The paper presents the results of research on the creation of a community based on lactobacilli and bacilli with antimicrobial activity against pathogens of intestinal infections in farm animals. B. subtilis strain MP 2 and L. plantarum strain MP 5 included in the consortium are characterized by resistance to artificial gastric juice and bile salts, as well as the ability to form extracellular hydrolytic enzymes (xylanase, carboxymethylcellulase, avicelase, β-glucosidase, amylase, phytase, protease and lipase), antimicrobial (acids, bacteriocins, siderophores and exopolysaccharides) and antioxidant metabolites. B. subtilis strain MP 2 and L. plantarum strain MP 5 did not have hemolytic activity and did not carry genes responsible for toxin production, which indicates the potential safety of this bacteria. It was concluded that the developed consortium is promising for use as a probiotic for animal husbandry.

In order to increase the level of production of hydrolytic enzymes of natural producers and select highly productive microorganisms, a study was carried out on the effectiveness of various approaches to induced mutagenesis, as well as a comparative study of the ability of exoenzymes biosynthesis by original and mutant strains. New mutant strains of B. subtilis and T. harzianum with some morphological deviations were obtained using multi-stage non-directional mutagenesis in a fractional mode followed by selection on selective media. These bacteria were superior to the parent strains of B. subtilis MB085-148-72 and T. harzianum MF091-07-305 in the number of hydrolytic enzymes produced. The stability of the characteristics of the new producers was confirmed by three successive subcultures on nutrient media containing the appropriate substrates of hydrolytic enzymes. Considering the high level of production of hydrolases of new strains of microorganisms, they can be recommended as components of feed additives, biopreservatives for silage and haylage, as well as effective producers of enzymes.

In order to study the effect of a number of 6-substituted uracil derivatives on bovine embryo lung cells, experiments were conducted. According to the study, the effect of the studied substances on the cultural and morphological properties of cell was determined by taking into account their viability and proliferation index. In %, it was calculated that viability was determined by the ratio of living cells to their total number. The proliferation index was determined as the ratio of the number of proliferating cells to the number of seeded cells. At 0.1 mM concentration of the compounds studied, a decrease in LEK cell viability was recorded compared to the control group, but this was only the case for compound No. 2. When other compounds were used at doses of 0.1 mM, LEK cell viability increased by 3.0-7.0% compared to controls. Increasing the dose of the compounds studied to 1.0 mM results in a 10.0% decrease in survival in the presence of compounds No. 3 and 6, 16.0% in the presence of compounds No. 2 and 7, 19.0% in the presence of compound No. 4 and 25.0% in the presence of compounds No. 8 and 9.

This paper presents research on the study of the adsorption properties of sorbents of mineral and organic origin. From the research results, it was seen that the maximum adsorption properties for zearalenone at room temperature of 19-21 ° C and pH 7 were shown by sorbents: bentonite of the Biklyansky deposits 34.7%, bentonite of The biklyansky burned 25.3%, bentonite of the tarn-Varna deposits 31.4% Mycosorb 65.7%, Phytosorb 57.5%, zeolite 27.3%, Zookarb 21.2% showed the lowest sorption capacity for zearalenone. In relation to the T-2 toxin, the adsorption properties of sorbents at a temperature of 19-21 ° C and pH 7 showed: Phytosorb 57.5%, bentonite of the Biklyansky deposits 51.7%, bentonite of the tarn-Varna deposits 57.4%, Mycosorb 55.7%, Zoocarb 43.8%, zeolite 36.2%, bentonite of the biklyansky fired 31.4%. According to the results of research, it can be concluded that when the average temperature increases from 20-21 ° C to 38-39 ° C, sorbents significantly increase the adsorption of toxins from 50-70% by such sorbents as phytosorb, Mycosorb, bentonite of the Biklyansky Deposit.

Antimicrobial properties of the new strains of micro-organisms isolated from natural sources of various ecological niches in the Moscow region and the Republic of Tatarstan were studied. Antifungal activity of isolates was detected in a test culture of toxin-producing microscopic fungi that can cause animal and plant diseases: Aspergillus flavus, Candida albicans, Fusarium oxysporum and Penicillium spp. Of the 46 studied micro-organisms of genera Bacillus, Lactobacillus, Lactococcus and Streptomyces isolates, there are four strains (Bacillus subtilis, Lactobacillus plantarum, Propionibacterium freudenreichii and Streptomyces spp.) that showed an ability to produce biologically active metabolites with a pronounced antimicrobial potential against phytopathogenic fungi metabolites. Based on the selected four strains, a Bacterial product LRV composition has been created. Scots pine, pedunculate oak and small-leaved linden seedlings with single and double foliar treatment and Bacterial product LRV at a concentration of 10 mL/L led to an increase in the growth of the aboveground part by 31.8, 51.9 and 25.4%, respectively, and the underground part by 25.0, 37.2 and 25.7%, respectively, compared to the control. The weight of seedlings at the end of the study exceeded the control variant by an average of 26.0, 44.0 and 78.0%, respectively. Plant protection Bacterial product LRV use did not have a significant effect on the group of molds that caused the powdery mildew and Schütte disease damage to trees. The Biological product LRV provided plant protection from fungal diseases caused by Lophodermium pinastri Chev. and Microsphaera alphitoides. [ABSTRACT FROM AUTHOR]

Greedy expansions with prescribed coefficients were introduced by V. N. Temlyakov in a general case of Banach spaces. In contrast to Fourier series expansions, in greedy expansions with prescribed coefficients, a sequence of coefficients {cn}n=1∞{\left\{{c}_{n}\right\}}_{n=1}^{\infty } is fixed in advance and does not depend on an expanded element. During the expansion, only expanding elements are constructed (or, more precisely, selected from a predefined set – a dictionary). For symmetric dictionaries, V. N. Temlyakov obtained conditions on a sequence of coefficients sufficient for a convergence of a greedy expansion with these coefficients to an expanded element. In case of a Hilbert space these conditions take the form ∑n=1∞cn=∞{\sum }_{n=1}^{\infty }{c}_{n}=\infty and ∑n=1∞cn2

Introduction. Nowadays it’s recommended to perform carotid endarterectomy (CEA) in up to 14 days after nondisabling stroke; the procedure is aimed at the prevention of recurrent stroke.The objective of this research was the comparison of short-term and long-term (12 months) outcomes with early (in up to 30 days) and delayed (30-180 days) CEA in patients who suffered strokes of various severities.Materials and methods. The research involved 88 patients who underwent CEA in the early stage (Group 1) and 88 patients who underwent CEA in their late period (Group 2). We assessed primary endpoints: ipsilateral stroke, myocardial infarction, 30-day Lethality, 30-day lethality after the surgery, any stroke or infarction (MACE). Secondary endpoints: the same parameters within 12 months after the surgery, post-surgery local or systemic complications, restenosis, changes in neurologic or cognitive status.Results. In 30 days we observed ipsilateral strokes in 3 patients in Group 1 (3.4 percent), it was lethal in 1 patient (1.1 percent). 170 of 176 (96 percent) patients were followed up for 12 months. One lethal stroke was registered in the group of late interventions (1.1 percent). No statistically significant differences were observed between the outcomes in early and late treatment groups. The severity of disability (mRS) in patients of the early intervention group was significantly smaller at discharge and in 12 months after surgery.Conclusion. The advisability of early CEA performance was proven by the absence of differences in post-surgery 30-day and longterm lethality as well as the progress of stroke or infarction with early or late CEA. In 12 months after the surgeries, significant improvement in neurologic status by mRS was only observed in the group of early interventions.

The article assesses stiffness of main trusses bolted connections in the railway bridges metal superstructures. The generally accepted approach for trusses of bridge structures analysis is to replace joints with hinges. This technique simplifies finding the forces in structure elements, but reduces the reliability of the design model. In this study, the finite element method implemented in the Ansys Mechanical software package is used. The process of determining the stiffness of the high-strength bolts joint connection is described in detail. The paper proposes formulas to determine rotation angles of the truss elements joint sections according to the finite element model analysis results. For two joints of a standard design, superstructure stiffness was determined: kN2 = 107183.06 kN×m/rad, kN3 = 137605.56 kN×m/rad. Graphs of bending moment on the rotation angle dependence were also made. It was concluded that the beam model of the structure shows underestimated values of the joints stiffness, and the difference with the stiffness determined for the detailed finite element model can reach 5.635.

The phenomenon of self-excitation of thermomechanical vibrations of current-carrying conductors, experimentally discovered by academician A.F. Ioffe, is of practical interest as a possible explanation of the phenomenon of galloping conductors of overhead power transmission lines (OHL) – low-frequency vibrations with frequencies of ~ 1 Hz and with amplitudes of the order of the static conductor sagging. To build the theoretical foundations of this phenomenon, as a special class of self-oscillating systems, it is necessary, first of all, a model of conductor vibrations in the OHL span. With regard to the most studied type of conductor vibrations, high-frequency aeolian vibration, excited by sign-alternating aerodynamic forces from the Karman vortex street, the classical model of a straight string is reasonably applied. However, to study low-frequency vibrations of the galloping type, it is necessary to take into account the effect of sagging of the conductor, the associated elastic tension and, in some cases, the nonlinear nature of the vibrations. The article presents two models for calculating the natural vibrations of sagging conductors (cables) within the framework of the technical theory of flexible threads, assuming the constancy of the tension force along the length. The first model describes linear oscillations of an elastic conductor in the sagging plane. For a system of equations with respect to the displacement components given in natural coordinates, an exact solution of the Sturm-Liouville problem with estimates of the frequency ranges arising is obtained. The second model describes nonlinear vibrations of an elastic conductor in the sagging plane and pendulum vibrations accompanied by an exit from it. The solution of the problem is based on the principle of possible displacements using the Ritz method. The structure of the frequency spectrum and the natural forms of transverse vibrations are studied. The developed models are intended for further investigation of thermomechanical vibrations of conductor and flexible cable systems.