https://nge.nung.edu.ua/index.php/nge/issue/feed Oil and Gas Power Engineering 2020-06-29T00:00:00+03:00 Андрій Петрович Джус (Andrii Dzhus) ngejournal@nung.edu.ua Open Journal Systems <p>The journal publishes materials based on the results of scientific and productive activity in the field of oil and gas complex in the following directions:</p> <p>Geology, exploration and geophysics of oil and gas fields</p> <p>Scientific and technical problems of petroleum engineering</p> <p>Materials, structures and equipment of petroleum complex facilities</p> <p>New solutions in modern equipment and technology</p> https://nge.nung.edu.ua/index.php/nge/article/view/516 Optimization of design and mode parameters of the well ejection system 2020-05-16T11:57:59+03:00 Ye. I. Kryzhanivskyy rector@nung.edu.ua D. O. Panevnyk den.panevnik@gmail.com <p><em>I</em><em>nsufficient energy performance of ejection equipment and a high probability of non-operating modes of its operation reduce the efficiency of downhole jet pumps. The method of determining the design and operating parameters of the well ejection system, which provide the maximum efficiency of the jet pump, is presented. The proposed algorithm for determining the optimal values of the geometric dimensions of the flowing part of the jet pump involves the construction of a series of pressure characteristics for different values of its geometric parameter, the calculation of the efficiency and the determination of the injection ratio and the relative pressure corresponding to its maximum values. During the studies, the main geometric parameter of the jet pump varied in the range from </em><em><br /></em><em>2 to 6, given that these geometric dimensions are used in jet devices common in the oil industry. The optimal dimensions of the current part of the jet pump are obtained in the process of studying its pressure characteristics, and the optimal dimensions of the washing system of the bit - in the process of studying the characteristics of the hydraulic system. The design of an </em><em>at-bit</em><em> ejection system, which allows to increase the mechanical drilling speed, the passage of the bit, to stabilize the moment on the bit, to reduce its level of vibration and to control the antiaircraft angles of the well is considered. The efficiency of using </em><em>at</em><em>-bit jet pumps is</em><em> in the following</em><em>:</em><em> an</em><em> increase in the mechanical drilling speed up to 18.7%, the passage of the bit up to 50.8%. The research established the optimal diameters of the working nozzle, mixing chamber and bit nozzles, the distance between the working nozzle and the mixing chamber, the injection ratio and the relative pressure of the </em><em>at-bit</em><em> jet pump. The obtained values </em><em>​​</em><em>of design and mode parameters exclude the occurrence of cavitation modes of operation of the ejection system and allow the operation of jet pumps with maximum efficiency.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/509 Development of energy efficient system of gas cooling of mobile diesel compressor stations of oil and gas industry 2020-04-28T00:14:13+03:00 S. I. Kryshtopa auto.ifntung@ukr.net L. I. Kryshtopa auto.ifntung@ukr.net M. М. Hnyp marichka_gnip@ukr.net I. M. Mykytiy auto.ifntung@ukr.net M. M. Tseber auto.ifntung@ukr.net <p><em>The developments of domestic and foreign specialists in the field of improving the energy efficiency of mobile diesel compressor stations of the oil and gas industry is studied. The disadvantages of existing mobile diesel <br />compressor stations in terms of their energy efficiency are identified. Theoretical studies of energy efficiency directions and designs of existing mobile diesel compressor stations have been carried out. It has been studied that for efficient operation of a compressor station it is rational to increase the load of compressors and organize the operation of equipment in energy-efficient modes. Ways to improve the energy efficiency of mobile diesel compressor <br />stations with various options are proposed. It has been established that the optimal way to increase energy <br />efficiency is to reduce the gas temperature to lower temperatures, in comparison with the existing gas cooling <br />systems of compressor stations. It is found that with an increase in the degree of pressure, the savings in gas <br />compression for a compressor with a promising scheme for intermediate gas cooling also increase. An indicator diagram of compressor stations with various cooling schemes has been built. The scheme of the existing system of multi-stage gas cooling of mobile diesel compressor stations is investigated. An improved energy-efficient cooling system for compressed gas by using the heat of compression of gases is proposed. The conclusion about the existence of a reserve to reduce the energy costs of compression due to the use of a coolant-cooler with a temperature significantly lower than the ambient temperature is presented. The description of the working processes of mobile diesel compressor stations according to the existing and perspective schemes is made.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/517 Analysis of tendencies of oil and gas engineering development 2020-04-21T14:55:54+03:00 O. V. Panevnyk o.v.panevnik@gmail.com D. O. Panevnyk den.panevnik@gmail.com <p><em>Based on the study of the dynamics of global costs for oilfield equipment, it was found that its production shows slow growth, the largest share of oil and gas machinery is in North America, and the largest segment of production belongs to the manufacture of equipment for collecting and transporting hydrocarbons and pipe products. In the process of analysis of the nomenclature and geography of production of machines, mechanisms, individual components and parts of drilling and oil and gas equipment, the inconsistency of the level of development of oil and gas engineering in Ukraine with the needs of the fuel and energy complex is shown. The required level of production of equipment and spare parts directly depends on the quality of maintenance of oil and gas machines, which with the development of new technologies for the development of hydrocarbon fields should increase. The main reasons for failures of oil and gas equipment are the lack of proper maintenance. Domestic oil companies are focused on the import of oil equipment, and a negative problem for the development of the domestic market of oil services is the reduction of their own production of oil and gas equipment. One of the most important competitive advantages of domestic service companies is a lower level of prices for services, as well as a deeper knowledge of the specifics and features of local conditions for the development of hydrocarbon deposits.</em><em> An important aspect of the development of the service market is the transition to innovative technologies in the field of geological engineering and drilling. In accordance with the development trends of the world oil and gas engineering industry, the staffing requirements of service companies are increasing. Given the complexity of mining and geological conditions for the development of hydrocarbon deposits, the development of new technologies for oil and gas production requires increasing attention to training specialists who </em><em>are aware of modern methods of design, operation and maintenance of oil and gas equipment.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/519 Analysis of residual gases of internal combustion engines at working on biogas and their effects on the environment 2020-05-05T08:53:32+03:00 T. V. Dykun ecm@nung.edu.ua V. I. Artym ecm@nung.edu.ua Ya. M. Demianchuk slavdem67@gmail.com F. V. Kozak ecm@nung.edu.ua L. I. Haieva esm@nung.edu.ua <p>Given the limited resources of Ukraine in petroleum fuels for internal combustion engines, the use of alternative fuels is quite relevant. One of their sources is biogas from livestock by-products and garbage dump. Ukraine has significant volumes of these renewable sources, the potential of which reaches more than 100 million tons of conventional fuel. Unfortunately, this resource is rarely used. In developed countries, biogas is widely used for electricity generation in power plants with internal combustion engines. Today in the United States the volume of biogas production is about 500 million m3 / year, in France – 40 million m3 / year. In the Czech Republic, Austria, Denmark, Finland and other countries, biogas is used as a motor fuel. Business Concerns Volvo, Scania produce buses running on biogas. In Ukraine, gas from landfills and livestock by-products is mostly released into the atmosphere or burned by flares, polluting the surrounding air. This causes additional greenhouse gas emissions. It is known that the main source of air pollution is vehicles. Exhaust, i.e. residual gases are considered toxic. The World Motor Vehicle Park annually emits up to 260 million tons of carbon monoxide, 40 million tons of volatile hydrocarbons, nitrogen oxides and others. The composition of the residual gases of the internal combustion en-gine depends on the component composition of the sources of fuel and, of course, on the mode of operation of the internal combustion engine In the given article the structure of residual gases of internal combustion engines at work on biogas is analyzed and their influence on environment is generalized. Based on analytical calculations, it is determined how the amount of residual gas components changes depending on the excess air ratio and the per-centage of methane in biogas. Recommendations for improving the performance of internal combustion engines on biogas by using it in mixtures with natural gas are given. According to the research results, the corresponding graphical dependences are constructed.</p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/527 Investigation of parameters of mixing and heat formation of diesel engines in the process of using alternative fuels 2020-06-16T09:22:32+03:00 V. M. Melnyk vasjamel@ukr.net M. M. Liakh vasjamel@ukr.net M. M. Synoverskyi vasjamel@ukr.net <p>Today in Ukraine and the world there is a growing shortage of commercial fuels for engines. This is due to the tendency to regulate the production of hydrocarbons, which is the main raw material for their production. Therefore, in order to reduce oil imports, alternative fuels for diesel engines based on oils and animal fats are be-coming more widespread today. In this regard, intensive work is underway to convert internal combustion engines to biofuels in countries with limited fuel and energy resources, as well as in highly developed countries that have the ability to purchase liquid energy. Biodiesel fuel (biodiesel, RME, RME, FAME, EMAG, etc.) is an environmentally friendly type of biofuel obtained from vegetable and animal fats and used to replace petroleum diesel fuel. In the process of using RME B100 biodiesel fuel on the Renault 2.5 DCI engine, the average diameter of the fuel droplets is increased and the flare opening angle is reduced. This leads to impaired fuel distribution in the areas of the spray torch. Only 50% of the fuel is in the jet shell, which leads to impaired mixing of fuel with air. In the core of the wall there is 18% of fuel, which will spread along the walls and mix poorly with air. The remaining 36% of the fuel will be in the core of the jet, the front of the free jet and the areas of intersection of the near-wall streams, and will partially participate in the mixing. The use of biodiesel fuel RME B100 leads to a delay of heat by 18-20 degrees of rotation of the crankshaft, which will increase fuel consumption and reduce engine power. Thus, according to studies of the Renault 2.5 DCI engine on commercial and biodiesel RME B100, it is established that the use of biodiesel leads to a deterioration of the mixture due to reduced heat and as a result increases fuel consumption, reducing engine power.</p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/512 Analysis of composition and dispersion of fuel emulsions 2020-06-03T14:29:37+03:00 V. O. Melnyk victor_11@ukr.net <p>The development of the economy of the state, as well as industrial enterprises, leads to an increase in demand for all types of energy carriers. This is characterized by the constant search and exploration of new progressive types of energy and sources of raw materials, especially for thermal power plant TPPs, CHPs and utilities, which use liquid fuel - usually fuel oil - to operate. For such enterprises, stable and timely supply of fuel raw materials, improvement of methods of its combustion, reduction in the cost of obtaining energy, etc. are relevant. Existing heavy hydrocarbon combustion technologies are of poor quality and it is therefore advisable to develop new ones or to optimize existing ones. This will reduce energy costs for technological preparatory operations for the de-watering of fuels, reduce the amount of polluted water reservoirs, and minimize their harmful effects on the envi-ronment. One of the most promising areas for combustion of heavy water hydrocarbons is the use of water emulsion fuels (WEF). The stability and efficiency of combustion of such a fuel emulsion will greatly depend on the amount and dispersion of water in the WEF. Today, such emulsification technologies and WEF parameters are not yet well understood and are therefore of great scientific and practical importance. The analysis of the theories describing the effect of dispersion and the amount of water in the emulsion on the combustion indices shows that they are contradictory. This can be due to the different physical characteristics of the fuel: composition, viscosity, temperature, etc., which has led to different results. Since studies by different authors were conducted under dif-ferent conditions, modes, equipment and with different fuel emulsions, it is not possible to indicate the optimum value of dispersion and amount of water. Obviously, in each case there will be a different optimal "surface" of the ratio of the size of the droplets of water and its number in the WEF. Future experimental and theoretical studies on the combustion of WEF should focus on the water content range of 3-30% and the dispersion of 1-35 microns.</p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/514 Improving the energy efficiency of a solar power plant 2020-06-15T11:33:04+03:00 I. R. Vashchyshak tvs.vitalik@gmail.com V. S Tsykh v.tsykh@nung.edu.ua <p>The urgency of the work is due to the feasibility of increasing the energy efficiency of solar power plants through the use of solar energy concentrators. Ways to improve the energy efficiency of solar panels using a sys-tem of directional mirrors, flat Fresnel lenses, spherical concentrators and trackers have been investigated. It is established that the most optimal way to improve the energy efficiency of solar panels is to use inexpensive track-ers with a simple design. The analysis of known types of solar panels, which differ in materials from which their elements are made, and the coefficients of efficiency – dependence of energy produced by a photocell on the intensity of solar radiation per unit of its surface has been carried out, and the type of solar panels by the criterion “price-quality” has been selected. A tracker design has been developed to track the angle of inclination of solar panels to increase efficiency. The electricity generated by the proposed solar power plant was calculated using an online calculator. It is projected to reduce losses when generating electricity for a given power plant due to the use of a tracker compared to a fixed power system, with the same number of solar panels. In order to reduce the cost of the tracker, it is suggested to orientate it to the south at once, and to change the inclination angles twice a year (in early April and late August). The energy efficiency of the power plant is calculated in two stages. At the first stage the amount of electricity from solar panels per year when adjusting only the angle of inclination of the panels to the south is calculated. At the second stage energy efficiency of the power plant is calculated taking into account the increase of energy efficiency of the solar power plant when using the tracker system. The calculated electricity generation of the proposed solar power plant with tracker confirmed the efficiency and feasibility of using the designed tracker system. The application of the designed tracker system allows to increase the energy efficiency of solar panels by an average of 25%.</p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/510 Analysis of wave disturbance in the drill string while releasing stuck pipes 2020-06-03T14:29:57+03:00 M. V. Lyskanych burewisnyk@gmail.com O. О. Slabyi burewisnyk@gmail.com 1 Berzhnytskyi burewisnyk@gmail.com <p><em>The work is devoted to testing the hypothesis about the possibility of assessing the nature of the release of the drilling tool by percussion devices by analyzing the response of the system in the form of vibration records of the upper end of the drilling tool. For this purpose, based on the examined existing theoretical models, a wave diagram of the propagation, reflection and interference of deformation waves caused by the operation of the percussion device along the tacked drilling tool is constructed. Based on the developed diagram, a prediction is made of the nature of the oscillatory processes of the upper end of the drilling tool of a typical design located in a vertical well and the nature of their occurrence is explained. Based on the presented theoretical model the authors made an analysis of records in relative units of the vibration velocity of the upper end of a drilling tool in two specific cases of freeing stuck drilling tools in wells No. 812-Pasichna and No. 903-Pasichna of Nadvirna and Ivano-Frankivsk UBR, where they used VUK-170 that worked in jar mode. For this purpose, the time-frequency representation of the obtained records in the form of spectrogram, scalogram and Wigner-Ville pseudo-distribution was performed, and, based on the obtained theoretical prediction of oscillations of the upper end of the drilling tool, the time of the following stages of the percussion cycle – striking, impact and post – was established. Based on the data obtained, a time-frequency impact assessment was carried out and the character of the attenuation of deformation waves in the drill string was evaluated. Based on the well-known arrangement of stuck drilling tools, the propagation speed of deformation waves along the drill string is determined, which turned out to be more than theoretically calculated for an ideal thin rod according to the wave equation. The paper considers further directions of development of the proposed approach, as well as the use of its results to increase the efficiency of the freeing of stuck tool using impact tools.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/529 Special features of tight gas reserves determination 2020-06-15T12:21:18+03:00 S. V. Krivulya skrivulya@ndigas.com.ua S. V. Matkivskyi matkivskij@gmail.com Ye. S. Bikman bikman.efim@ndigas.com.ua O. R. Kondrat kondrat@nung.edu.ua O. V. Burachok oburachok@slb.com <p><em>Special features of tight gas reserves determination, based on material balance method, were characterized, since reliability of initial hydrocarbons in place determination plays important role in future field development planning, particularly on recovery rate, wells to be drilled, capital expenditures, surface facilities etc. Using the synthetic 3D model of gas reservoir, different development scenarios were evaluated according to the different spatial distribution patterns of petrophysical properties within the reservoir. Analyzing the obtained results, the authors fully confirmed an assumption made, that significant heterogeneity of reservoir properties makes a great impact on the shape of pseudo reservoir pressure curve vs cumulative gas produced and introduces significant errors into determination of initial gas in place. At the late stages of the development, the slope of P/z straight line changes, and this allows determination of much greater reserves’ volumes. Usage of pseudo reservoir pressure vs cumulative produced gas for determination of drained reserves in tight gas formation is especially risky, because the production data can indicate the true volumes of gas in place, only after the majority of the gas been produced. In most cases, the development period to acquire necessary data for correct volumes in place estimation exceeds the planning period. This factor introduces the significant error into future field development during the planning phase. Due to that, at the initial development stages, the error in drained volumes estimation can account for 50% out of true initial volumes in place. Based on conducted research, the potential error evaluation for tight gas reservoirs initial gas in place determination with decline pressure material balance method was performed. According to the results of computer simulation, the error can account for 25% from true initial gas in place in simulation model. This error significantly excesses the acceptable limits and can lead to wrong decisions in development planning</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/511 Improving the efficiency of gas pipeline cleaning by controlling the speed of the gas cleaning 2020-04-30T14:38:51+03:00 V. Ya Grudz v.grudz@nung.edu.ua N. B. Slobodian nazar.slobodian28@gmail.com <p><em>An important aspect of improving the hydraulic efficiency of pipeline transport is its periodic cleaning with mechanical cleaning devices. Cleaning gas pipelines with cleaning pistons is a technologically complex process. It is advisable to adjust the speed of the piston to increase the efficiency of cleaning the pipeline with the crossed track profile. On the ascending and plain sections of the route, maintain a high speed of movement of the device, and on the descending it to reduce. To slow down the movement of the piston in the downstream sections of the main gas pipelines, it is proposed to change the technological scheme of the linear part. It is suggested to use a looping connection to change the flow chart. The change of the speed of movement of the treatment device when changing the technological scheme of the main gas pipeline was evaluated. The influence on the dynamics of the movement of the cleaning piston of the main parameters of the pipeline and looping, as well as the parameters of the movement of the piston itself, are investigated. A mathematical model of the process is built, on the basis of the implementation of which the regularities of the treatment device movement when changing the technological scheme of the gas pipeline are established. An equation was obtained to find the ratio of the mass flow rates of gas in the main gas pipeline before and after connecting the loop, which can be solved by the iteration method. The algorithm is developed and the program of calculation of the degree of reduction of the speed of movement of the piston is developed, depending on the kind of technological parameters and technical characteristics of the treatment device and the pipeline. Based on the calculations, the graphical dependences of the relative speed of the piston on the technological parameters and technical characteristics of the main pipeline were constructed. The authors found that the greatest effect on the degree of reduction of the speed of the piston has the length of the loop. It has been investigated that a decrease in the initial pressure and an increase in the final pressure, as well as an increase in the pressure drop at the moving boundary, lead to an improvement in the braking conditions</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/518 Development of technology for repair of shaped elements of pipeline systems in hard-to-reach places 2020-05-04T20:34:46+03:00 Ya. V. Doroshenko jaroslav.doroshenko79@gmail.com <p><em>It is proposed that erosion or corrosion worn out bends of pipeline systems in hard-to-reach places be repaired by trenchless methods by pulling a sleeve or a flexible composite pipe with a piston. The possibility of implementing such an idea is confirmed by theoretical and experimental studies. Mathematical modeling of the process of pulling a sleeve by a piston by a pipeline that contains a defective tap is performed. Formulas are derived for determining all resistance forces acting on a mobile system, patterns of pressure changes at the compressor outlet during such work are determined. A technique has been developed for calculating the friction force between the sleeve and the inner wall of the pipeline at the outlet, due to the pressing of the sleeve through a change in the direction of pulling. The dependence of the required pressure for the piston to extend the sleeve only with a defective bend on the bend angle of the bend is determined. An experimental setup has been developed and built to study the dynamics of the sleeve pulling by a piston. As a result of the experimental tests, it was found that it is possible to extend the sleeve through a pipeline with a piston that contains bend. The resistance forces acting on the moving system, the patterns of pressure change at the beginning of the pipeline in time when the sleeve is pulled by the piston, are experimentally determined. The experimental results are compared with the results of theoretical calculations and the reliability of theoretically derived dependencies is confirmed. The technique and technology for repairing defective pipe bends in hard-to-reach places has been developed by pulling a sleeve or a flexible composite pipe with a piston. The piston moves under the pressure of the air supplied to the piston space by the compressor. A drum with a wound sleeve or flexible composite pipe is placed in a cylindrical sealed chamber. A special supporting device has been developed to place a flexible composite pipe wound into a bay in a cylindrical sealed chamber.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/521 Monitoring of tension state of pipelines by magnetic anisoтropic method 2020-06-03T14:28:45+03:00 V. V. Tsyhanchuk cigan@i.ua L. S. Shlapak cigan@i.ua O. M. Matviienkiv cigan@i.ua <p><em>The known methods of investigation of mechanical stresses that can be applied to pipelines are reviewed. Both domestic and foreign samples are described. On the basis of the conducted critical analysis, the most promising methods of control are identified and one of their main disadvantages is indicated: the estimation is performed according to the diagram of the dependence of the magnetic properties on the mechanical stress of the metal. Given this, an advanced electromagnetic voltage meter INI-1C is proposed. At the heart of the design is a modernized node processing information signal on the Arduino platform. The essence of the innovation lies in the use of analog-to-digital signal conversion and subsequent processing of the software package. This, in turn, provides a calculation of the dependence of the signal change on the mechanical force. Consequently, it was possible to achieve convenient visual control on the electronic display of the monitor or smartphone. It is proposed to use a magnetic control method with a four-pole magneto-anisotropic converter as the most suitable for practical application. The Arduino hardware and software platform was used to enhance the capabilities of the INI-1C mechanical stress measuring instrument. The system of remote monitoring for periodic measurements of line pipeline voltages, accumulation and analysis of the obtained data with the purpose of providing objective information for making technological decisions is described. Thus, using the introduction of remote pipeline monitoring systems, you can monitor the status of the entire pipeline in real time. The monitoring is carried out without violating the integrity and stopping of the pipeline.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/513 Mathematical modeling in the problems of the geodesic control of the stressed-formated state of the gas pipelines at above-ground parts 2020-04-30T14:53:12+03:00 O. Yu. Korobkov olehkorobkov@gmail.com Ye. Y. Ripetskyi уrip@i.ua R. Y. Ripetskyi romrip@i.ua R. Ye. Oleskiv roksolanaoleskiv@gmail.com <p><em>Geodetic methods of monitoring the stress-strain state of gas pipelines in the areas of overhead pipeline crossing involve obtaining discrete data on the deformation of its axis in the form of a set of three coordinates (x, y, z). For their elaboration a mathematical model of the experimental-theoretical method of geodetic control of gas pipelines’ SSS is proposed. The simulation process was performed on the basis of geodetic discrete data, based on which, using the Lagrange interpolation polynomial, the equation of the line of bending of the axis of the gas pipeline was obtained, which allowed to pass further to the bending moments along the entire span. The accuracy of the proposed method has been estimated, which showed that the obtained bending moment diagrams reflect the SSS of gas pipelines with an accuracy of 1.5% in the central part of its span, and with the approach to the peripheral sections the error increases to</em> <em>6%.</em> <em>It is shown that the obtained expression of the maximum bending moment allows us to form the required number of additional equations for the disclosure of a statically indeterminate system of "gas pipeline-support", taking into account the possibility of fastening on stretch marks. The mathematical model is presented aimed at decomposition of overburden gas pipeline structures, which allows to model the SSS at each of the spans separately within the integral structure.. It is established that additional stretch marks reduce the maximum bending stress by 22%, and in case of loss of one of the stretches of the bearing capacity of the gas pipeline SSS increases by 11.1-14.8% depending on the previous stretch tension.</em> <em>The proposed mathematical model for the processing of discrete data forms the basis of the experimental-theoretical method of geodetic control of the gas pipelines’ SSS, taking into account their structural and technological factors.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering https://nge.nung.edu.ua/index.php/nge/article/view/531 Dynamic torsion of underground pipeline due to sudden rotation of foundation fragment 2020-06-19T15:37:46+03:00 M. I. Vaskovskyi Vaskovskyi@naftogaz.com <p><em>In the paper, we study the strength of underground pipelines, which are laid through tectonic faults, and, as a consequence, are operated in difficult mining and geological conditions. In such dangerous areas, in addition to the standard pressure load of the transported product, the pipe is subjected to additional effects from the movements of the inhomogeneous, often damaged, foundation. Predictably, the most dangerous situation is when such movements are transient. The paper aims at developing a model to describe the non-stationary process of pipeline deformation on a damaged foundation caused by sudden mutual rotations of rock blocks around the pipe axis. The dynamics of the pipeline was studied in a linear formulation, modeling it with a rod with a tubular cross-section. The momentless theory of cylindrical shells and the energy concept of strength were used while considering the issues of ultimate equilibrium. The soil backfill was considered as Winkler's elastic layer. Local continuity disturbances of the foundation are described by a sudden rupture of the angle of rotation of its fragment. This approach, developed on the problems of statics, makes it possible to dynamically assess the strength of the underground pipeline not by <br />external load from the soil, which is usually unknown, but by the observed or predicted parameters of the fault edges. We formulated an initial-boundary value problem for a hyperbolic differential equation of torsion with a discontinuous right-hand side. Based on the analytical solution of the problem, constructed in the form of squares from Bessel functions, the influence of the sudden rotation of the foundation fragment around the pipe axis on the stress-strain state of the pipeline is studied. Plots of the space-time distribution of the angle of rotation, angular velocity, torsion deformation and equivalent stresses of von Mises in the prefrontal and postfrontal areas are constructed. It is established that considering dynamic effects leads to an increase in the torsion deformation maxima and the equivalent stress in the pipe wall in comparison with the case of static perturbation.</em></p> 2020-09-03T00:00:00+03:00 Copyright (c) 2020 Oil and Gas Power Engineering