Natural Gas Transportation Research Articles

Sustainability and environmental impact in the LNG value chain: Current trends and future opportunities

The liquefied natural gas (LNG) industry plays a crucial role in the global energy landscape, offering a cleaner alternative to traditional fossil fuels. However, the LNG value chain presents environmental challenges that must be addressed to ensure long-term sustainability. This paper examines current trends and future opportunities for enhancing sustainability and reducing environmental impact across the LNG value chain. The LNG value chain comprises several stages, including natural gas extraction, liquefaction, transportation, regasification, and distribution. Each stage presents unique sustainability challenges, such as methane emissions during extraction and transportation, energy-intensive liquefaction processes, and the carbon footprint of regasification and distribution. Current trends in the LNG industry focus on mitigating these challenges through various strategies. These include the adoption of advanced technologies for methane detection and reduction, the use of renewable energy sources for liquefaction, and the implementation of efficient regasification and distribution practices. Additionally, there is a growing emphasis on stakeholder engagement, transparency, and reporting to enhance sustainability performance across the value chain. Future opportunities for improving sustainability in the LNG value chain lie in the continued development and deployment of innovative technologies. These include carbon capture and storage (CCS) technologies to reduce emissions, the use of renewable natural gas (RNG) as a feedstock, and the integration of LNG with renewable energy sources to create hybrid energy systems. Addressing sustainability and environmental impact in the LNG value chain requires collaboration among industry stakeholders, governments, and regulatory bodies. By implementing best practices, embracing innovation, and prioritizing sustainability, the LNG industry can continue to play a vital role in the transition to a cleaner and more sustainable energy future.

Design and Effect Evaluation of a Hydrogen–Natural Gas Mixing Device at Jingbian Compressor Station

Abstract Hydrogen gas is an environmentally friendly alternative energy source with zero emissions, making it highly valuable for replacing fossil fuels and reducing carbon emissions. One effective method of transporting hydrogen gas is by injecting it into existing natural gas pipelines. In this research, we focus on the Jingbian compressor station. This station is used for hydrogenation, blending hydrogen with the natural gas flowing through the pipelines. We propose a suitable process for hydrogen blending and design a mixing device to facilitate this process. To evaluate the mixing effect of the blended gas, we conducted numerical simulations to analyze the velocity and concentration distribution along the continuous section of the hydrogen blending pipeline. The results indicated that achieving a hydrogen branch length of 1/2 the diameter of the natural gas main pipe and a hydrogen flowrate of 10% resulted in a nonuniformity of hydrogen concentration at L = 30D of less than 0.05. Furthermore, when the hydrogen concentration was set at 3%, 10%, and 30%, the hydrogen concentration in the cross section of the pipe gradually approached the expected concentration as the mixed gas flowed. It is worth noting that during transportation of hydrogen-containing natural gas to the outlet, the velocity distribution on the cross section remained asymmetric, potentially leading to measurement errors. However, the use of a flow conditioner resulted in a further reduction in hydrogen nonuniformity and minimized velocity fluctuations, resulting in a small and uniformly distributed flow, which is advantageous for accurate measurement and transportation purposes.

Erosion model of silicon carbide ceramics and YW3

In this study, an erosion model of silicon carbide ceramics and YW3 was established by combining experimental and numerical simulation data. This model can be applied for the prediction of erosion in natural gas equipment and transportation systems and also provides ideas for the establishment of erosion models. The erosion model was established by using quartz sand, brown corundum, and glass beads as abrasive materials, and then the accuracy of the erosion model was confirmed by numerical simulations. The results showed that when the abrasive was quartz sand, brown corundum, or glass beads, the erosion angle at which the maximum erosion of silicon carbide and YW3 occurred was related to the type of abrasive. When the abrasive was quartz sand, brown corundum, and glass beads, the velocity index n of silicon carbide was 3.24, 3.66, and 3.32, respectively, and the model constant k was 4.1959 × 10−11, 3.6436 × 10−11, and 4.1838 × 10−11, respectively. The velocity index n of YW3 was 2.29, 2.41, and 1.87, respectively, and the model constant k was 2.6176 × 10−7, 3.0017 × 10−7, and 3.1040 × 10−7, respectively. When the test results were compared with the numerical simulation results, the maximum error for silicon carbide was 6.59%, 7.71%, and 9.25%, respectively, and the maximum error for YW3 was 8.78%, 9.51%, and 5.97%, respectively. Finally, the erosion model of silicon carbide ceramics and YW3 was established via a large number of experiments and numerical simulations. When the target material and abrasive material are the same, it can be directly used for erosion prediction and structure optimization of natural gas equipment. Meanwhile, this paper provides a new idea for the establishment of gas–solid two-phase erosion model, and when the abrasive material and target material change, a new erosion model can be established according to the idea of this paper.

Application of four intelligent models for the estimation of formation pressure of natural gas hydrate

Natural gas hydrate is a clean and efficient resource that contains lots of heat energy. The production, processing and transportation of natural gas can be influenced dramatically by natural gas hydrate. Natural gas hydrate will accumulate at the bottom of the pipeline, even block the pipeline and reduce the flow rate of the natural gas. This article presents four intelligent models named GWO-SVM (Grey Wolf Optimizer connected with Support Vector Machine), GWO-LSSVM (Grey Wolf Optimizer connected with Least Squares Support Vector Machine), GA-LSSVM (Genetic Algorithm connected with Least Squares Support Vector Machine), and GWO-RBF (Grey Wolf Optimizer connected with Radial Basis Function) to predict the formation pressure of natural gas hydrate in different systems. In order to determine the degree of influence of each input variable on the formation pressure of natural gas hydrate, this paper uses Spearman correlation analysis method to calculate the correlation coefficients between the formation pressure of natural gas hydrate and various influencing factors. The contradistinction among different intelligent models shows that the GWO-LSSVM model has the exceptional performance of the smallest average absolute relative deviation (AARD=2.89%), the minimum standard deviation (SD=0.05) with all 244 data of natural gas hydrate formation pressure in different systems. When compared to six commonly used empirical models for predicting formation pressure in common natural gas hydrate, the GWO-LSSVM model has the highest prediction accuracy, with an AARD of only 1.82%. Furthermore, when compared to three thermodynamic models employed for predicting formation pressure in sour natural gas hydrate, the GWO-LSSVM model has the highest prediction accuracy, with an AARD of 2.38%. The leverage method demonstrates that four intelligent models have excellent robustness in reflecting the inner relationships among natural gas hydrate formation pressure and influential factors. The four intelligent models for predicting hydrate formation pressure will be helpful to find hydrate formation pressure in different systems.

Atomic-scale investigation of the mechanisms of deformation-induced martensitic transformation at ultra-cryogenic temperatures

Liquefied natural gas storage and transportation as well as space propulsion systems have sparked interest in the martensitic transformation and behaviours of 316 L stainless steels (SS) under ultra-cryogenic deformation. In this study, high-resolution transmission electron microscopy (HRTEM) and molecular dynamics (MD) simulations were used to investigate the atomic arrangements and crystalline defects of deformation-induced γ-austenite → ε-martensite → α′-martensite and γ → α′ martensitic transformations in 316 L SS at 15 and 173 K. The γ → ε transformation involves the glide of Shockley partial dislocations on (111)γ planes without a change in atomic spacing. The formation of an α′ inclusion in a single ε-band is achieved by a continuous lattice distortion, accompanied by the formation of a transition zone of α′ and the expansion of the average atomic spacings due to dislocation shuffling. As α′ grows further into γ, the orientation relationship (OR) of the α′ changes by lattice bending. This process follows the Bogers-Burgers-Olson-Cohen model despite it not occurring on intersecting shear bands. Stacking faults and twins can also serve as nucleation sites for α′ at 173 K. We also found that direct transformation of γ → α′ occurs by the glide of 6aγ[112¯]/12 dislocations on every (111)γ plane with misfit dislocations. Overall, this study provides, for the first time, insights into the atomic-scale mechanisms of various two-step and one-step martensitic transformations induced by cryogenic deformation and corresponding local strain, enhancing our understanding of the role of martensitic transformation under ultra-cryogenic-temperature deformation in controlling the properties.

Time varying reliability analysis of corroded gas pipelines using copula and importance sampling

Ensuring the safety of gas pipelines is crucial for the reliable and efficient transportation of natural gas. This study introduces a methodology for evaluating the time-varying reliability of corroded gas pipelines. The proposed approach employs both importance sampling and copula theory to effectively address the uncertainties associated with random variables involved and provide efficient estimates of failure probability. Small leak and burst failure modes are specifically investigated within this study. The methodology first establishes a step-by-step procedure for analysis. Subsequently, the study investigates the failure probability of corroded gas pipelines, taking into account both small leak and burst failures, under scenarios involving single and multiple defects. Furthermore, the study examines the influence of correlation strength and dependence structure among the involved random variables using the copula theory. Additionally, the generation of newly formed defects is thoroughly investigated, along with its impact on failure probability. Numerical examples are provided to evaluate the performance of the proposed methodology, comparing it with the benchmark failure probability estimated through Monte Carlo simulation. The results validate the precision and efficiency of the proposed methodology, while offering practical and insightful suggestions for reliability analysis of real-world gas pipelines.

DETERMINATION OF OPERATING PARAMETERS OF A CRYOGENIC TANK FOR LOW-TONNAGE STORAGE OF LNG

In the modern world, the gas industry plays a key role in the fuel and energy complex of any country, ensuring energy security and economic development. With the constant consumption of natural gas, there is a need for efficient methods of its transportation and storage. One of the ways of transportation and storage of natural gas is its liquefaction.In the case of low-tonnage liquefied natural gas (LNG) production complexes, where we are talking about small volumes of production of the order of several thousand tons of LNG per year, in comparison with large-tonnage production, where productivity amounts to millions of tons of LNG per year, the efficiency of storage processes comes to the fore, as this allows for reliable and economically feasible operation of small-scale LNG complexes.In this context, determining the operating parameters of cryogenic tanks for low-tonnage storage of liquefied natural gas is becoming an urgent research topic. The method of storing cryogenic products in semi-insulated tanks has a number of advantages, such as low energy consumption, high efficiency, and long storage time.This article is devoted to determining the parameters of the cryogenic tank operation during low-tonnage storage of liquefied natural gas. The study is aimed at determining the parameters of the cryogenic tank operation based on the calculated heat flow to the stored LNG. In this paper, the authors developed and compared various calculation schemes of heat inflow, which considered such factors as heat transfer by radiation, convection and conduction, including heat inflows to LNG through thermal bridges and from the combined-cycle phase of stored liquefied gas.The result of the study is the revealed method for determining the heat flow to LNG stored in a cryogenic tank, which is optimal in terms of the accuracy of the results obtained and the simplicity of calculations. The results of this study can be used in the further development of storage technologies for both liquefied natural gas and other industrial gases.

Experimental study on hydrogen-enriched natural gas jet fire hazards: Assessment of the flame geometrical parameters

In the future, hydrogen will be more frequently injected into natural gas networks for storage and transportation purposes. A diffusion jet flame forms when gaseous fuel leakage occurs during the transportation or utilization of hydrogen-enriched natural gas, and the fuel is ignited by an ignition source in still air. In the study, methane was chosen to simulate natural gas. Experiments with the hydrogen addition fraction reaching up to 20% were performed to study the effects of the initial flame angle (θ = 90°, 60°, 30°, 0°, and −30°), variable nozzle diameter (de = 3.15, 4, 4.94, 5.65, and 6 mm) and a multitude of fuel flow rates (10, 20, 30, 40, 50, and 60 L/min) on the morphological parameters of the gas jet flames. The geometrical features of the jet flame were determined via video processing for each experiment. The geometrical parameters of hydrogen-enriched natural gas were quantified under different conditions. The experimental results indicate that a dimensionless prediction model was established for the flame height of hydrogen-enriched natural gas by modifying the flame Froude number (Frf) for vertical jet flames. For upward jet flames, the normalized flame horizontal projection length (Lx) of hydrogen-enriched natural gas is well correlated with Q∗. A global prediction model for inclination angles of 0° ≤ θ ≤ 60° and 2000 < Q∗<20,000 was proposed based on the experimental data. For downward jet flames, the normalized horizontal projection length and downward extension length (Ld) of the hydrogen-enriched natural gas jet flame are correlated with Q∗, with powers of 2/5 and 3/5, respectively. Dimensionless prediction models for the horizontal projection length and downward extension length are given by modifying the flame Froude number. Quantitative results were proposed in order to gain insight into the development of the key parameters and the effects on the environment, from which extinguishing concepts and safety areas can be directly derived.

A Simplified Method for the Evaluation of Floating-Body Motion Responses over a Sloping Bottom

Recently, many floating renewable energy platforms have been deployed in coastal regions, where sloping bottoms are an important factor when evaluating their safety. In this article, a simplified method coupling an eigenfunction matching method (EMM) and a finite-depth Green’s function (FDGF) is developed to evaluate floating-body motion responses over a sloping bottom for which bathymetry is homogeneous in the longshore direction. We propose an extended EMM to create an incident wave model over the sloping bottom, thereby obtaining the Froude–Krylov (F–K) force and Neumann data on the wet surfaces of the floating body for the diffraction problem. An equivalent depth is introduced to account for the interaction between the sloping bottom and floating bodies when dealing with the diffraction and radiation problems. The accuracy of the present method is validated through a comprehensive comparison with numerical and/or experiment results for a liquefied natural gas (LNG) ship and a floating hemisphere from the literature. Generally, the present, simplified method can give predictions with sufficient accuracy.

Competitiveness of Export-Oriented Systems of Long-Range Energy Supply

The paper examines process chains including production, transport, and conversion of energy resources from Siberia and the Russian Far East to Asian countries. The study aims to find the most effective ways to supply energy to end consumers at various distances. The options considered include pipeline transport of natural gas from eastern regions of Russia to Asian countries; rail transport of coal from Russian export-oriented deposits to Asian countries; natural gas conversion into methanol, with methanol transport through pipelines of various diameters to Asian countries; and coal conversion into methanol, with methanol transport through pipelines of various diameters to Asian countries. Optimization is performed using previously developed mathematical models.

Elasticity evaluation and improvement of natural gas network based on prior information aided decision-making strategy

The natural gas pipeline is the dominant approach for long-distance natural gas transportation, the safety and efficiency of which are of great significance. Faced with various potential hazards, the elasticity of natural gas pipelines against abnormal events has not been discussed. This work categorizes these abnormal events into three types according to their influences on the pipelines and proposes a method to evaluate and improve elasticity against these abnormal events. By introducing elastic residue energy, indexes to assess elasticity were defined across six dimensions of operational efficiency. An intelligent decision-making strategy based on prior information is proposed to enhance pipeline elasticity. Through simulations on a practical natural gas pipeline segment, the performance of the proposed strategy is discussed. The proposed strategy is validated as effective under the three types of abnormal events, with elasticity increasing by 144%, 28%, and 12%, respectively, which can be considered a significant improvement.

Effect of Entrainment on the Liquid Film Behavior in Pipe Elbows

Multiphase flow entrainment in natural gas engineering significantly influences the safety and efficiency of oil companies since it affects both the flow and the heat transfer process, but its mechanisms are not fully understood. Additionally, current computational fluid dynamics (CFD) methodologies seldom consider entrainment behavioral changes in pipe elbows. In this article, a verified CFD method is used to study the entrainment behavior, mechanism, and changes in an elbow. The results show that droplet diameter in a developed annular flow follows a negative skewness distribution; as the radial distance (from the wall) increases, the fluctuation in the droplets becomes stronger, and the velocity difference between the gas and the droplets increases linearly. Turbulence bursts and vortices sucking near the wall jointly contribute to droplet entrainment. As the annular flow enters the elbow, the secondary flow promotes the film expansion to the upper and lower parts of the pipe. Droplets re-occur near the elbow exit intrados, and their size is much smaller than those in the upstream pipe. Vortices sucking under low gas velocity play an important role in this process. These findings provide guidelines for safety and flow assurance issues in natural gas production and transportation and bridge the gap between multiphase flow theory and natural gas engineering.

Effects of leucine on hydrate formation: A combined experimental and molecular dynamics study

Compared to conventional natural gas storage and transportation methods, hydrates offer a safer, more compact alternative with broad future potential. To enhance hydrate formation, there has been considerable interest in environmentally friendly and cost-effective amino acid promoters, such as leucine. This study utilized a transparent vessel for CH4 hydrate formation experiments, identifying the optimal 0.5–0.6 wt% leucine concentration, which led to enhanced gas consumption, shorter induction time, and maximum gas storage density. In the leucine system, hydrates exhibited distinctive branching growth on container walls, both upward and downward. The formation of numerous microchannels amplified capillary effects, enhancing gas–liquid contact and fostering hydrate formation. Simultaneously, isobaric-isothermal molecular dynamics (MD) simulations integrated system growth configurations, structural parameters, radial distribution functions, energy barriers and mean square displacements, unveiling leucine’s microscopic impact on hydrate formation. Simulation results unequivocally show that leucine significantly accelerates CH4 hydrate growth by momentarily adsorbing at the solid–liquid interface, expediting water molecule ordering into cage-like structures. Leucine also enhances water molecule structural order around the mobile leucine molecule. Moreover, leucine lowers the energy barrier for methane transitioning from gas to liquid, facilitating gas molecule diffusion into the liquid phase and affording plenty interaction time for water and methane molecules, thereby providing favorable conditions for hydrate formation. These findings provide crucial perspectives for future research in the field of eco-friendly hydrate promoters, paving the way for innovative solutions in natural gas storage and transportation.

Resolving hydrate inhibition mechanism: Interactions between kinetic hydrate inhibitors and CH4 bubble

The kinetic hydrate inhibitors (KHIs) are known to be both economical and eco-friendly in preventing hydrate blockages. To date, two main inhibition hypotheses of KHIs have been proposed, in which the dominant interactions are KHIs-crystals and KHIs-aqueous, respectively. However, both hypotheses experience challenges as contrary phenomena are frequently observed. Herein, we find the extensively generated CH4 bubble in hydrate exploitation or natural gas transportation can greatly promote hydrate nucleation, thus, a new inhibition mechanism is proposed based on the interaction of KHIs-CH4 bubble. Specifically, PVCaps (one typical KHI) can absorb on CH4 bubble surface to mitigate CH4 dissolution, which thus i) reduces the concentrations and accommodations of CH4 in aqueous, thereby mitigating the formation of hydrate embryo; ii) decreases CH4 transfer from bubble to embryo, thereby mitigating the growth of hydrate embryo. As both the formation and growth of hydrate embryos are inhibited, the hydrate nucleation requires longer induction time and larger critical nucleus. Moreover, this new mechanism has been found to be applicable to other KHIs, in which the interaction strengths of KHIs-CH4 bubble can successfully explain the experimental inhibition efficiencies of PEO < PVP < PVCap < VIMA. Thus, the interaction of KHIs-CH4 bubble can act as the key criterion in screening and designing effective KHIs.

Defect Recognition Method for Magnetic Leakage Detection in Oil and Gas Steel Pipes Based on Improved Neural Networks

The aging infrastructure of petroleum and natural gas pipelines poses a threat to national economies, necessitating precise defect detection for safety and efficiency. To enhance the accuracy of predicting pipeline defect sizes, this study introduces a magnetic leakage detection system, employing Backpropagation (BP) neural networks optimized with genetic algorithms. Traditional BP networks face challenges, including parameter determination and slow convergence, addressed through genetic algorithms' global search capabilities. Simulated data are generated using ANSYS software by using models of semi-circular defects in steel pipes, producing magnetic leakage signals of varying intensities. MATLAB was used to construct both standard BP and genetically optimized BP neural networks. Results show that the latter significantly reduces computational errors, demonstrating improved accuracy in defect dimension prediction. The approach contributes to overcoming non-uniqueness in the recognition process and the complex nonlinear relationship between magnetic signals and defect size parameters. The study offers a guided approach for selecting BP neural network parameters, enhancing practicality. Simulations validate the method's effectiveness, indicating low workload and high reliability. This research provides a meaningful advancement in the detection of defects in long-distance pipelines, impacting the safety and efficiency of petroleum and natural gas transportation.

Investigation on coupling deposition and plugging of hydrate and wax in gas–liquid annular flow: Experiments and mechanism

The coupling deposition and plugging caused by hydrate formation and wax precipitation during the development of deep water natural gas resources bring new industrial challenges and theoretical difficulty. We designed a single-pass pipeline with two types to investigate deposition behavior and systematically performed the coupling deposition and plugging of hydrate and wax experiments in gas–liquid annular flow. The experimental results illustrate that the single solid phase of hydrate is covered layer sheet deposition, while the coupling solid phase of hydrate and wax is bulk aggregations arch bridge deposition. Meanwhile, the natural eddy zone in reducing pipeline accelerates coupling solid particles deposition. Our finds provided the first knowledge on the double effect that wax crystals inhibit particles adhesion and gel network increases aggregations arch bridge blockage. For the low water content in emulsion system, the gel network provides gathering place for hydrate particles, and the arch bridge structure formed by aggregations accelerates the pipeline blockage. The plugging time is shortened by up to 72.6% with the wax concentration increase from 0 wt% to 3 wt%. For the high water content in emulsion system, the majority of wax crystals adsorbed on the hydrate particles and reduce particles cohesion force, which increase the plugging time. Combined with the microscopic morphology evolution perspective of hydrate particles coupled wax, the coupling deposition of hydrate and wax in gas–liquid annular flow has four stages: gas–liquid flow, coupling solid phase formation, coupling solid phase deposition and sloughing, and coupling solid phase plugging. This study can provide theoretical support and design basis for flow assurance program of deep water gas fields and low temperature natural gas transportation pipelines.

A Multi-objective Optimization Method for Simulating the Operation of Natural Gas Transport System

A Multi-objective Optimization Method for Simulating the Operation of Natural Gas Transport System

Current state and prospects of the Chinese gas market

The purpose of the study. Analyze the state of the Chinese gas market, the relationship between the problem of imported gas supplies and economic factors for the chain of the Chinese gas industry.Methodology. The research is based on the methods of an economic and mathematical model for the efficiency of natural gas transportation, a weighted average multi-index indicator, analysis of statistical data, study of scientific and journalistic literature. The value of research. The authors of the article identified topical issues of ensuring energy security, considering the trends of the global and Chinese gas market and the opportunity for further international cooperation. The recommendations proposed by the authors are of real importance for understanding the Chinese gas market.The results of the study. The authors of the article analyzed data on the demand and consumption of natural gas in China, as well as on the indices of the supplier countries in recent years. It is concluded that the Chinese gas market has great potential for the development of energy cooperation, and China also concluded that it is highly dependent on imports in the structure of gas consumption. Pipeline gas is an important source of natural gas imports to China and one of the main guarantees of energy security. Based on the results of the analysis, the prospects of cooperation between China and such supplier countries as Kazakhstan, Turkmenistan and Russia in the gas industry are substantiated.

Simulation of the Jet Fire Using Atmospheric Dispersion Modeling (ALOHA): A Case Study of Natural Gas Pipeline in Istanbul, Türkiye

Natural gas is known as a widely used energy source in residential, business and industrial areas. During the transportation of natural gas by pipelines, accidents occur due to various reasons, which can also lead to gas output. These accidents are events that have the potential to pose important risks in terms of life and property safety, particularly in urban areas and surrounding of pipeline routings. In this study, accident scenarios were generated based on a natural gas distribution pipeline fire that occurred in Istanbul (NW Türkiye) on 28 April 2020 and the impact areas of the jet fire were calculated using the ALOHA program. The effects of source release factors (i.e., pipe length and diameter) and atmospheric conditions (i.e., wind speed, cloud cover, air temperature and relative humidity) on the thermal radiation threat distances associated with jet fire were calculated for the current and worst scenarios. As a result, it was found that pipe length and diameter have a significant effect on threat distances. In addition to the role of the synoptic circulation mechanism on the jet fire for the selected episodic event (position of low/high pressure centers), local atmospheric conditions also have an effect on the threat distance. From the modeling analysis, significant impact of wind speed, air temperature and relative humidity values on the threat distances were found. In the worst scenario, if there were strong northeasterly winds reaching 30.9 m per hour at the time of the jet fire, the threat distances would have been 21 m (red), 28 m (orange) and 42 m (yellow). This case shows that if a natural gas jet fire occurs under the influence of strong northeasterly winds (passing over the Black Sea without encountering any topographic obstacles), poisonous gas will be transported to long distances in a short time and will negatively affect social life and economy.

ON THE RELIABILITY AND MAINTAINABILITY OF INDIVIDUAL ELEMENTS OF GAS DISTRIBUTION SYSTEM VALVES

At the current stage of the development of society, including in our country, there is an accelerating urbanisation process. The increasing role of cities in the country’s development, on the one hand, contributes to social, scientific, and technical development, and on the other hand, creates new economic, ecological, informational, social, and other challenges. One of the features of urbanisation is the increase in energy use. One of the primary sources of energy is natural gas. Transportation of natural gas from deposits and gas storages and its distribution to consumers occurs with the help of gas transportation systems. One of the components of gas transportation systems is gas distribution systems. They have a broad range of components and elements and a long list of requirements for the conditions of their manufacture, operation, and repair, and they are under the influence of numerous external factors. Such multivariability necessitates the development of specific models, methods, and information technologies for monitoring their state in conditions of uncertainty to solve the problems of forecasting and planning repair work on gas transportation systems. During the study, we determined the main factors affecting the reliability of gas pipelines overall. We also analysed the operational characteristics of the shut-off valves of elements of gas distribution systems, typical malfunctions, and the main features of its diagnosis and repair. During operation, gas distribution system elements are under the influence of many factors that affect their reliability. Considering all the factors arising at different stages of the life cycle of the gas distribution system elements will ensure their operational reliability, indestructibility, and durability. The results of the analysis of individual parameters of shut-off fittings of gas distribution systems are applicable for creating models and methods of monitoring, forecasting, and planning repair work on gas transportation systems under conditions of uncertainty. Keywords: shut-off valves, models and methods of monitoring, reliability, repair, defects.