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Summary In this study, unique field data analysis and modeling of operating wells with an extended horizontal wellbore (HW) and multistage hydraulic fracturing (MHF) in the Bazhenov formation were conducted. Moreover, a large amount of long horizontal well data obtained from the Bazhenov formation field was used. Wells with extended HW drilling and MHF are necessary for commercial oil production in the Bazhenov formation. Problems can occur in such wells when operating in the flowing mode and using an artificial lift at low flow rates. This study aimed to describe the field experiences of low-rate wells with extended HWs and MHF and the uniqueness of well operations and complexities. It was also focused on modeling various operation modes of such wells using specialized software and accordingly selecting the optimal downhole parameters and analyzing the sensitivity of fluid properties and well parameters to the well flow. The flow rates in wells with extended HW and MHF decrease in the first year by 70–80% when oil is produced from ultralow-permeability formations. Drainage occurs in a nonstationary mode in the entire life of a well, leading to complexities in operation. A comprehensive analysis of field data [downhole and wellhead pressure gauges, electric submersible pump (ESP) operation parameters, and phases’ flow rate measurements] and fluid sample laboratory studies was conducted to identify the difficulties in various operating modes. For an accurate description of the physical processes, various approaches were used for the numerical simulation of multiphase flows in a wellbore, considering the change in the inflow from the reservoir. The complexities that may arise during the operation of wells were demonstrated by analyzing the field data and the numerical simulation results. The formation of a slug flow in low flow rates in a wellbore was caused by a rapid decline in the production rate, a decrease in the water cut, and an increase in the gas/oil ratio (GOR) over time. Based on the results, proppant particles can be carried into the HW and thereby reduce the effective section of the well in case of high drawdowns in the initial period of well operation. Consequently, the pressure drops along the wellbore increased, and the drawdown on the formation decreased. Other difficulties were determined to be associated with the consequences and technologies of hydraulic fracturing (HF). These effects were shown based on the field data and the numerical simulation results of the flow processes in wells. In addition, corrective measures were established to address various complexities, and the applications of these recommendations in the field were conducted.

The problem of the interaction of a shock wave with an increased-density gas bubble in the neighborhood of the wall is investigated on the basis of numerical simulation of Euler’s equations in the two-dimensional plane formulation. The process of shock wave refraction and focusing, namely, reflection of transverse shocks from the plane of symmetry of flow and the wall, is described. It is found that qualitatively different flow regimes, in which the wave is focused in the plane of symmetry before or after the beginning of wave reflection from the wall, can be implemented depending on the constitutive parameters of the problem. It is shown that the presence of a heavy bubble in the neighborhood of the wall strengthens multiply the pulse shock-wave loading on the wall. The maximum pressure reached on the wall is found as a function of the impinging wave Mach number, the bubble gas density, and the initial distance between the bubble and the wall. In some cases such a dependence is essentially nonmonotonic with respect to the bubble gas density and the distance between bubble and wall.

The paper is devoted to the non-coplanar interplanetary Earth–Venus flight of a spacecraft equipped with a non-perfectly reflecting solar sail, the magnitude and direction of acceleration from which is calculated taking into account specular and diffuse reflections, absorption and transmission of photons by the surface of the solar sail. The goal of the heliocentric motion is to transfer the solar sail spacecraft into the Hill sphere of Venus with zero hyperbolic excess of speed. A feature of the paper is the study of the motion of a non-perfectly reflecting solar sail spacecraft taking into account the motion relative to the center of mass. The problem is divided into three stages. At the first stage, a nominal program for controlling the motion of the spacecraft center of mass is formed. At the second stage, sufficient angular velocities are determined to ensure the obtained nominal control program and the parameters of the spacecraft controls – thin-film controls located along the perimeter of the solar sail – are calculated. The operating principle of the thin-film controls is quite simple. When the voltage applied to the thin-film controls changes, they become transparent or opaque, there is a difference in the normal components of the light pressure forces, which provides a control torque for changing the orientation of the spacecraft in space. At the third stage, the joint motion of the center of mass and relative to the center of mass of the spacecraft is simulated to demonstrate the feasibility of the obtained control program. As a result, a comparison is made of non-coplanar interplanetary Earth–Venus flights with and without thin-film control elements.

The article examines the intelligence of the company as the main factor and the result of the socio-economic activity of the enterprise. It is noted that the intelligence of a company depends on the quality of the subjects of the nano-level - the employees of the enterprise. In this regard, the role of modern forms of organization of economic activity and promising management practices, on the basis of which a new type of industrial relations is formed, which determines the system intelligence of enterprises, is analyzed. Self-managed (collective) enterprises are one of these perspective forms of management. It is shown that the development of intelligence is characterized by the formation of emancipative values of participants in democratic governance. At the same time, a high level of development of the company's employees participating in self-man-agement enhances the intelligence of the enterprise and reduces the transaction costs of conducting economic activities.

The paper is devoted to the non-coplanar interplanetary flight Earth-Venus of the spacecraft equipped with a solar sail. The goal of the heliocentric movement is to transfer a spacecraft with a non-perfectly reflecting solar sail into the Hill’s sphere of the Venus with zero hyperbolic excess speed. The magnitude and direction of acceleration is calculated taking into account specular and diffuse reflections, absorption and transmission of photons by the surface of the solar sail. One of the main tasks in the field of navigation and motion control of a spacecraft is the search for a simple energy-efficient control scheme for performing maneuvers during flight. These control schemes are locally optimal control laws, various combinations of which allow you to perform the necessary maneuvers during an interplanetary flight. The procedure for the formation of a control program for a non-coplanar interplanetary flight of the Earth-Venus type of a spacecraft with a non-perfectly reflecting solar sail is described. The results include the flight trajectory, the change in phase coordinates in time, graphs of changes in control angles, and the nominal control program. The obtained results satisfy all the boundary conditions described in the statement of the problem.

A noncoplanar controlled heliocentric flight to Venus of a spacecraft with a non-perfectly reflecting solar sail is considered. The aim of the heliocentric flight is to get a spacecraft into Hill sphere of Venus with zero hyperbolic excess velocity. An algorithm has been developed for applying the locally optimal control laws for the fastest change of the osculating elements. Solar sail orientation is controlled by thin-film control elements arranged along the solar sail surface perimeter. The flight trajectory, the control program and the required width and area of thin-film control elements are obtained as a result of motion simulation.

We have detected subterahertz spectral lines in the emission of free-running GaAs/AlGaAs quantum cascade lasers (QCLs) operating around 3 THz. We have found that the power W( fd) of an individual sub-THz line at the frequency fd is directly proportional to a power product W( fi) × W( fk) of the corresponding pair of THz lines having the frequency difference fi − fk = fd. The established one-to-one correspondence of each sub-THz line to pair combinations of THz lines proves the nonlinear mechanism of difference-frequency generation (DFG) in the QCL active region. The conversion efficiencies W( fi − fk)/[ W( fi) × W( fk)] estimated from the experimental data are about 4 × 10−3 and 5 × 10−5 W−1 for the sub-THz lines found at 132 and 310 GHz, correspondingly. Considering nonlinear polarization of QCL active regions as the reason for DFG, we have evaluated the following values of the second-order nonlinear susceptibility χ(2)(132 GHz) ≅ 7 × 105 pm/V and χ(2)(310 GHz) ≅ 4 × 104 pm/V from the experimental data. The obtained results pave the way for the use of THz QCLs as sources of sub-THz radiation.

HgCdTe is promising as a material to solve a problem of the development of semiconductor sources with an operational frequency range of 6–10 THz due to the small optical phonon energies and electron effective mass. In this study, we calculate the dependence of the metal–metal waveguide characteristics on the number of cascades for the 3-well design HgCdTe-based quantum cascade laser at 8.3 THz. It is shown that four cascades are sufficient for lasing at a lattice temperature of 80 K due to the large gain in the active medium. The results of this study provide a way to simplify the fabrication of thin active region HgCdTe-based quantum cascade lasers for operation in the range of the GaAs phonon Reststrahlen band inaccessible to existing quantum cascade lasers.

The paper considers a spatial controlled heliocentric Earth-Mars flight of the spacecraft with a non-perfectly reflecting solar sail. A new mathematical model of motion is described, taking into account the dynamics of motion relative to the center of mass under the action of forces and torques from light pressure. To implement the flight, a spacecraft control algorithm was formed based on local optimal control laws for the steepest change in osculating elements. The orientation of the solar sail is controlled by thin-film controls located around the perimeter of the solar sail surface. As a result of motion simulation, the duration and trajectory of the flight, the control program, and the necessary design parameters of the spacecraft with solar sail were determined.

We report on a sapphire-fiber-based lens that can be used to enhance the emitted THz power of a large-area photoconductive antenna (PCA). Using numerical simulations, we demonstrate that the lens provides a spatial redistribution of the photocarriers density in the PCA’s gap. By optimizing the diameter of the sapphire-fiber, one could reach efficient confinement of the photocarriers in the vicinity of the PCA electrodes with a 10- μ m gap size for a 220- μ m-thick sapphire-fiber. This allows enhancing the coupling of the incident electromagnetic waves at the interface between the sapphire fiber and the semiconductor with the antenna terminals by ∼40 times for a single PCA element, as well as boosting the total efficiency of the large-area PCA-emitter up to ∼7–10 times. To validate our approach, we propose a step-by-step process that can be used for the precise and controllable placement of the sapphire-fiber on the surface of a single PCA.

Beginning from the 1990s, an ever-lasting interest in the terahertz (THz) spectroscopy and THz instruments has produced wide progress in the development of high-speed THz detectors. The constantly growing requirements aimed at the increase of spectral resolution, sensitivity, and acquisition rate of THz detectors have attracted much attention in this field. In the present review, we summarize the most recent advances in the THz photodetectors based on semiconductor structures with quantum confinement of an electron gas. Their main advantages over existing detectors are fast response time, increased spectral resolution, and multicolor operation thanks to the variability of their designs and band structure engineering. These all allow for using them in various important applications such as single photon detection, THz heterodyne detection, continuous monitoring of toxic gases, THz free space communications and radio astronomy.

Over the past two decades, the operation temperature of terahertz quantum cascade lasers (THz QCLs) has continuously increased from cryogenic level to the current record value of 250 K (about -23°C) [1]. Here we review the state-of-the-art and future prospects of high-temperature THz QCL designs with two-quantum wells in active module based on conventional heterojunction GaAs/AlGaAs and alternative material system HgCdTe. We have analyzed the temperature dependence of the peak gain and predicted the maximum operation temperatures of the given designs.

Maximum physical exercise has a negative effect on physiological and morphological processes in the body. However, in some cases, the body responds with adaptive properties, which leads to smoothing out the negative effects of exercise. Establishing causes and factors that positively affect the processes of adaptation to increased activity and identifying the mechanisms of this process is one of the urgent problems of adaptation. Adaptation processes have a certain structure, and therefore, the goal of our research was to study the physiological processes and morphogenesis of individual organs and systems of the animal organism. One of the first to conduct a comprehensive assessment of the histological changes in experimental animals when giving adaptogens against the background of maximum activity. As adaptogens, the components of the military nature were used, tincture of safflower-like leuzea and ovesol, which were administered for 28 days at a dose of 2 to 6 μl according to the developed scheme. In this case, ovesol was used only at the final stage of the experiment from 22 to 26 days. It was found that ultra-high physical exercise leads to histological and physiological changes in the body of experimental animals.

When performing maximum physical activity, the main role for maintaining motor activity and homeostasis of the animal body is given to the kidneys. In this regard, the purpose of our research is to study morphological changes in the body of laboratory animals during physical exertion and the use of biologically active substances. One of the first to carry out a comprehensive assessment of the histological changes in experimental animals when given adaptogens (tincture of moral root, pantocrine and a combination of the same drugs with oats) against the background of maximum loads. The dosage of adaptogens was calculated according to the method proposed by Clark, based on the live weight of the animals. Which was 2 μl at the beginning of the experiment, subsequently the dosage was increased to 6 μl for all experimental groups. The first group was given distilled water, and the experimental group received leuzea tincture and oatsol. Ovesol was poured in a dose of 4 μl from 22 to 26 days. The total duration of the experiment was 28 days. It was also found that the use of tincture of moral root (safflower leuzea) and pantocrine prior to physical exertion makes it possible to correct histological changes.

Due to the fact that it is important for athletes to restore the physiological functions of the body after physical exertion, it is necessary to develop corrective measures. One of such methods can be the use of adaptogen preparations of various origins. In this regard, the goal of our research was to study morphological changes in the body of laboratory animals during physical exertion and the use of biologically active substances. For this, the object of the study was mice, the subject of the study was an adaptogen of plant origin - tincture of safflower leuzea, and of animal origin - tincture of pantocrine. Distilled water was used in the control group of animals. Research data carried out for 28 days indicate that in the body of mice, over the limit loads lead to a violation of morphogenesis in a number of internal organs. It has also been established that the use of tincture of leuzea safflower and pantocrine before physical exertion allows you to correct and stabilize the physiological functions of the body of animals, and in particular, the physiology and morphogenesis of the skeletal muscles of animals. The best effect was manifested from the use of an adaptogen of plant origin.

Difficulties in ERP systems implementation at Russian enterprises are characterized by the following aspects: firstly, automation of non-optimized processes, “chaos automation”; secondly, inefficiency of the implementation process; thirdly, the problems of integration with the existing systems at the enterprise; and fourthly, lack of interest in the project on the part of the company management, which leads to the customer’s disappointment and that’s why 40–70% of ERP implementation projects fail. To avoid the problems stated above, the integrated approach to improvement of the enterprise management system was worked out in a company. This approach includes the following stages: organizational and process transformations, business processes automation, and change of the control and analysis system.

A generalized statement of the problem of determining the stress-strain state of sandwich plates with a transversally soft core in the presence of constraints is proposed. Its correctness is discussed. The generalized problem is stated as the problem of finding a saddle point of some functional. The existence and uniqueness of a solution is proved. An iterative method for solving the problem is proposed and its convergence is studied.

The paper is devoted to the assessment of the possibility of implementing Big Data techniques for processing large amount of data to identify cause-effect relationships (patterns) that precede an event and to develop proactive measures to prevent them. To carry out such an assessment, existing sources of information, communication channels, and database structures were studied. Based on the analysis and the pilot project, areas of possible introduction of operational and forecasting analytics were identified. The required volume and structure of the data for analysis of data in the Big Data analytical complexes were evaluated with identification of patterns preceding various emergency situations during ESP operation, such as jamming, overheating, unsuccessful start-up, etc. Recommendations for the ESP operation data collection, storage and processing are developed. Events chain visualization examples related to emergency ESP shutdowns and unsuccessful starts are shown using the Aster analytical system. Sankey diagrams showing cause-effect relationships distribution are constructed. Analysis of these models has yielded several results. Estimation of the average time for putting the well into the "Normal Work" mode after a shutdown showed that when starting automatically, unlike manual start-up, the time savings can be from 30 minutes to one hour. That is, the proper ESP's control station configuration combined with smooth startup precautions can significantly reduce the equipment downtime and oil production losses. Analysis of the time series anomalies associated with the ESP motor loading revealed a pattern - starting load exceeded 80% lead to a subsequent system underload, and then - to an emergency stop. Pattern causes analysis revealed that, in low gas content in the wellbore conditions the ESP with an overestimated start-up frequency, quickly removes liquid from the annulus to a critical level, followed by an ESP gas lock and shutdown. Another revealed pattern shows that unsuccessful starts often occur when high-temperature motor protection and low-pressure protection are triggered. The analysis of the ESP's control station settings showed a strong correlation of the start-up problems with the improper ESP's control station settings. An analytical model of the data during the research made it possible to analyze other phenomena related to malfunctions in the operation of pumps. We are talking about the effect of turbine rotation, which leads to the drainage of the produced liquid from the tubing when the motor is stopped. Since the ESP control station clearly fixes the time of the end of the turbine rotation, it was possible to determine oil losses and build check valves rating. The use of the big data tools made it possible to formulate and test a set of hypotheses about the causes of emergency shutdowns and failures in the ESP startup associated with improperly configured protections and the PVT properties in control station. Several observations obtained during the experiment considered be to used for programming ESP's control stations. During the analysis, it was noted that often the separation of different well's data between different groups of specialists or departments creates obstacles for a comprehensive analysis. So, production data and formation properties, downhole equipment operation data, electricity consumption data, hydraulic measurements in the well and on the surface, should ideally be stored in one database and analyzed jointly. Unfortunately, this obvious consideration is often underestimated in practice.

This article deals with developing production mode of gas lift operation of production wells. A method for solving the issues associated with immediate assessment of the potential flow rate of a large number of wells, as well as for the search of candidates for wellwork is presented. A method for solving optimization problems that arise in operation of gas lift wells on offshore is proposed. Examples of using the proposed method at offshore oil fields of the Socialist Republic of Vietnam that are operated by JV Vietsovpetro are shown.

The paper addresses the issue of intensive urban development in the area of Kemerovo-city. Underestimation of geotechnical conditions of the area at the project and construction stages results in negative geological processes such as erosion, waterlogging, soil subsidence, and underflooding. These processes can lead to deformation and failure of buildings and constructions.

We present the results of experimental investigations of interaction between femtosecond laser pulses of gigawatt power and suspended distilled water droplets of millimeter size. The angular distribution of the spectral characteristics of water particle emission is investigated.

The purpose of this paper is to present a rare clinical case of primary uterine cervix melanoma. Clinical data and histological specimens were a material for this investigation. The paper describes a case of primary uterine cervix melanoma in a 47-year-old patient who visited a gynecologist for contact bleeding from the genital tract. Squamous cell carcinoma was diagnosed by primary biopsy. Histologically, this tumor was referred to as a mixed tumor: there were large cell fields with epithelioid morphology and high mitotic activity among the small cell component. No pigment was detected. Immunohistochemical examination revealed the pronounced cytoplasmic expression of S-100 and a melanocytic cocktail (HMB-45 + tyrosinase + MelanA), a negative reaction in the tumor cells with smooth muscle actin and desmin and a positive reaction in the preserved myocytes, and the expression of cytokeratin AE1/AE3 exclusively in the non-keratinized surface stratified squamous epithelium. Primary epithelioid amelanotic melanoma was diagnosed.Цель исследования - представить редкий клинический случай первичной меланомы шейки матки. Материалом исследования послужили клинические данные и гистологические препараты. В статье представлен случай первичной меланомы шейки матки у пациентки 47 лет, обратившейся к гинекологу в связи с контактными кровянистыми выделениями из половых путей. При первичной биопсии поставлен диагноз плоскоклеточной карциномы. При гистологическом исследовании операционного материала опухоль имела смешанное строение: среди мелкоклеточного компонента определялись поля крупных клеток с эпителиоидно-клеточной морфологией и высокой митотической активностью. Пигмент выявлен не был. При иммуногистохимическом исследовании определены выраженная цитоплазматическая экспрессия S-100 и меланоцитарного коктейля (HMB-45 + тирозиназа + MelanA), отрицательная реакция в опухолевых клетках с гладкомышечным актином и десмином и положительная в сохранных миоцитах, экспрессия цитокератина АЕ1/АЕ3 исключительно в покровном многослойном плоском неороговевающем эпителии. Поставлен диагноз первичной беспигментной меланомы эпителиоидно-клеточного строения.

Using software for engineering calculations in oil production is a common practice. Wide spread software packages often focused on solving specific tasks - downhole equipment design, well performance analysis etc. Multiple wells calculations using standard software can be tricky. Moreover, visualization for multiple calculations results even trickier task with standard software. A convenient way for presenting the results of the multiple calculations is construction of applicability maps. This paper discuss artificial lift technologies applicability maps construction. Applicability maps become useful for choosing lifting technique or analyze efficiency of current lift method in comparison with alternatives. It allows performing sensitivity analysis based on two most affecting on technology applicability parameters. In addition, maps can show technology applicability ranges which can be overlapped with production or forecast data. The paper proposes a simplified method for constructing artificial lift (AL) applicability maps. It discusses natural flow, ESP and gas lift. Methods allows building maps on the fly, taking into account the main AL limitations with respect to multiphase flow and PVT properties. Case studies for Western Siberia fields in with AL applicability maps analysis discussed.

One of limitations of achieving full potential in pumped wells is due to the presence of excessive free gas at pump intake. The presence of free gas at pump intake has several effects on the pump performance. A reduction in the pressure drop developed by the pump is usually observed when pumping multiphase flow mixtures. This performance reduction sometimes may be severe, resulting in unstable pump operation, production losses and may lead to premature equipment failure. Electric submersible centrifugal pumps (ESP) are commonly used in Russia and other parts of the world for oil production. Currently operators are being required to produce wells under non conventional and challenging operational conditions. One of such conditions is the use of ESP in wells with a high free gas liquid ratio that requires the use of special technology. Under those circumstances it is very important to understand more profoundly the processes of ESP operation as any mistake in the equipment design may have severe economical consequences. One of the crucial information needed is the technical limiting operational conditions for different ESP technologies when handling high gas liquid ratio mixtures. Determination of the technical operational envelope is itself a challenge. Experimental work conducted in Universities and industry research centers are very important for an understanding of the problem and advance of the technologies. But it is difficult to recreate in the lab the same conditions that exist in a well bore. Working with actual fluids at high temperatures and pressures are still challenging conditions to be reproduced in the lab. Therefore theoretical models, experimental correlations manufactures technical guidelines need to be verified against the conditions existing in a real oil well. This work presents the conclusions of the use of state of the art engineering methods describing the reservoir-pump-production system to analyze the performance of gas handling technologies based on real well field test results. The field tests were conducted under the New Technologies System project of Rosneft Oil Company. Field tests estimated technical limits for ESP gas handling technologies for up to 75% of volumetric gas fraction at pump intake conditions, as well as confirmed the possibility of oil production enhancement with the tests (the NPV for 11 ESP tested was more than 40 mln. rubles in 2007). It is estimated that more than a 100 wells would benefit from ESP gas handling technologies in Purneftegas alone, yielding significant economic impact for the company, increasing oil production by more than 700 tons/day.

Congenital deafness is a severe, incurable and hardly correctable inherited disease. Mutations in GCB2 and GJB6 genes are most prevalent causes of deafness and occur in patients with hereditary and sporadic deafness all over the world. Some ethnic groups exhibit high rate of heterozygous carriage of most frequent GJB2 mutations (35delG, 167delT, 235delC). Definite association of hereditary deafness and mutational alterations in genes of connexins 26, 30 and 31 shows high informative value of molecular-genetic methods which diagnose hereditary deafness, carriage of mutations in GJB2, GJB3 and GJB6 genes, provide definite probability of the disease in medico-genetic consulting. Further progress in genetics of hereditary hearing loss will raise efficacy of deafness diagnosis at early stages of fetal development and prevent birth of babies with congenital defects of sound perception.

Mesophilic and thermophilic groups of methanogenic bacteria were found in untreated fowl manure. The thermophilic anaerobic fermentation of fowl manure leads to the development of both individual methanogens utilizing only some of the methane precursors, and syntrophic associations that are also able to utilize complex substrates. The selection of methanogenic bacteria during fowl manure anaerobic fermentation results in accumulation of thermophilic forms utilizing acetate and propionate.