Pipeline Operation Research Articles

Analysis of a third‐party action incident in a gas pipeline: A case study of the Cuiabá Lateral Pipeline in Brazil

AbstractThe impact of third‐party actions remains a primary cause of induced failures in transportation systems. In response, the operational safety management system needs continual revision and robust implementation to mitigate such risks effectively. This study goes through the analysis of an incident involving the rupture of a gas pipeline, specifically examining the event that happened in January 2021 along the Cuiabá Lateral Pipeline in Mato Grosso, Brazil. A comprehensive comparative evaluation is undertaken, contrasting the investigation taken by the pipeline operator, and the analysis conducted by the regulatory body. Within the Brazilian context, operators are mandated to adhere to the Technical Regulation of Onshore Oil and Gas Pipelines (RTDT), a regulatory framework grounded in process safety, encompassing requirements for inspection, community engagement, and incident investigations. The regulator assumes an important role in evaluating the investigations carried out by operators. This research sheds light on the divergent perspectives surrounding the management system, depending on whether it is viewed from the operator's lens or the regulator's standpoint. operators tend to emphasize community actions, whereas regulators focus on the efficacy of preventive measures against third‐party actions, underscoring the significance of inspection frequency.

Research on the characteristics and protection of water hammer in long-distance dual-pipe water supply systems.

Hydraulic transients in long-distance pressurized water pipelines significantly impact their normal operation. This study develops a one-dimensional mathematical model for pressurized water pipelines using the method of characteristics and incorporates water hammer equations for dual-pipeline systems. The model is validated with experimental data, and simulations are conducted under real engineering conditions, focusing on valve closure operations. The analysis examines the transient responses for varying valve closure times (T) and the effect of installing surge tanks. Results show that increasing valve closure time and installing surge tanks both mitigate water hammer impacts. Specifically, when valve closure time exceeds 300 seconds, surge tanks reduce maximum pressure below the pipeline's tolerance (Pmax) and decrease the number of nodes experiencing damaging negative pressures. This model effectively simulates hydraulic transients in dual-pipeline systems and provides a foundation for developing protective measures for pipeline operations.

Аnalysis of the Actual Condition of Pre-Insulated Pipelines of District Heating Systems After Operation

The article discusses issues related to the actual condition of pre-insulated (PI) pipelines of district heating systems (DHS). Some of the pipelines in operation are approaching their estimated service life, so the issue of their further use is relevant. The aging of the heating supply pipelines occurs due to various processes associated with both operating temperature regimes and oxidation. The durability of polymer materials used in pre-insulated pipes can be assessed through empirical or predictive methods. For six batches of PI pipes that were in operation at different times in the Minsk DHS, tests were carried out according to standardized parameters in order to determine their actual values. For most of the samples presented, the values of the average cell size, thermal insulation density, compression strain stress and the number of closed pores significantly meet the requirements of STB 2252–2012 for new pipes. The value of the thermal conductivity coefficient is in the range of 0.030 to 0.037 W/(m·K), which is 10 % higher than the required value for new pipes. Values of the shear strength limit of the pre-insulated pipe construction in many tests was less than 0.12 MPa, indicating a potential risk of failure in the thermal insulation structure of the pipe. Besides, there is no specific correlation with either the service life of the pipes or the temperature regime.

Full-Scale Testing of Corrosion Resistant Alloy-Mechanically Lined Pipes for Submarine Pipelines

Abstract This study evaluates the fatigue performance of Corrosion Resistant Alloy–Mechanically Lined Pipes (CRA-MLPs), focusing on the critical triple point, where the CRA liner, weld overlay, and backing steel pipe intersect. Through Full-Scale Bending Tests (FSBT) and Full-Scale Resonance Fatigue Tests (FSFT), real-world operational and installation conditions were simulated to assess fatigue resistance, particularly at the triple point–an area not adequately addressed in current industry standards. The results reveal that the triple point exhibits excellent fatigue performance, exceeding the criteria of existing guidelines, despite the lack of specific provisions for this critical region. This study provides valuable data to inform updates to industry standards, enhancing the safety and reliability of subsea pipeline operations.

Consequence of high-pressure CO2 pipeline failure: Full-scale burst test and numerical simulation

Carbon Capture and Storage (CCS) is a widely acknowledged technique for mitigating global warming. High-pressure pipelines emerge as the most efficient and economical means to transport Carbon Dioxide (CO2) from source to storage sites. Given the hazardous nature of CO2 and the potential for catastrophic consequences in an unplanned release, ensuring safe operation of CO2 pipelines is paramount. This necessitates a comprehensive understanding of the potential consequences of CO2 pipeline failures. This paper presents experimental measurements of CO2 dispersion profiles following a full-scale burst test, simulating a real-world CO2 pipeline failure scenario. The experimental setup comprised an 82.7 m buried pipeline test section with a diameter of 324 mm, connected at both ends to 60 m reservoirs. The rupture of the pipeline was initiated at the middle of the test section using an explosive charge. Measurements were carried out for the transient downwind CO2 concentrations and temperatures following the explosive release. Computational Fluid Dynamics (CFD) models employing proposed numerical methods were used to simulate the experimental scenario. The performance of these methods was validated through comparisons with experimental measurements. The validated numerical methods were then employed to predict consequence distances for full-scale CO2 pipeline failures in real-world scenarios.

Mathematical Approach for Directly Solving Air–Water Interfaces in Water Emptying Processes

Emptying processes are operations frequently required in hydraulic installations by water utilities. These processes can result in drops to sub-atmospheric pressure pulses, which may lead to pipeline collapse depending on soil characteristics and the stiffness of a pipe class. One-dimensional mathematical models and 3D computational fluid dynamics (CFD) simulations have been employed to analyse the behaviour of the air–water interface during these events. The numerical resolution of these models is challenging, as 1D models necessitate solving a system of algebraic differential equations. At the same time, 3D CFD simulations can take months to complete depending on the characteristics of the pipeline. This presents a mathematical approach for directly solving air–water interactions in emptying processes involving entrapped air, providing a predictive tool for water utilities. The proposed mathematical approach enables water utilities to predict emptying operations in water pipelines without needing 2D/3D CFD simulations or the resolution of a differential algebraic equations system (1D model). A practical application is demonstrated in a case study of a 350 m long pipe with an internal diameter of 350 mm, investigating the influence of air pocket size, friction factor, polytropic coefficient, pipe diameter, resistance coefficient, and pipe slope. The mathematical approach is validated using an experimental facility that is 7.36 m long, comparing it with 1D mathematical models and 3D CFD simulations. The results confirm that the derived mathematical expression effectively predicts emptying operations in single water installations.

EFFECTIVE DOSAGE OF CORROSION INHIBITORS FOR OILFIELD EQUIPMENT PROTECTION FROM LOCALIZED CARBON DIOXIDE CORROSION

The article presents the results of laboratory tests of the industrial corrosion inhibitor VITERASOYUZ-2000 of the BP-2 brand (class of imidazolines) used in the oil and gas industry. In 2021, one of the vertically integrated companies purchased 20 thousand tons of this reagent, which is 10 % of the total purchased volume. The volume of corrosion inhibitors purchased by the company annually (~ 200 thousand t) is 97 % a product of domestic manufacturers. The main line of inhibitors purchased in 2021 is represented by the following brands: Sonkor (> 40 thousand t), Azol (~ 40 thousand t), Kormaster (> 30 thousand t), UnoKem (~ 30 thousand t), VITERASOYUZ (~ 20 thousand t), Scimol (> 10 thousand t), ETK (~ 10 thousand t), others (~ 20 thousand t). These reagents were used to inhibit carbon dioxide, hydrogen sulfide and mixed corrosion of oilfield equipment.In order to evaluate the effectiveness of inhibitors in suppressing local carbon dioxide corrosion and determine their effective dosage laboratory studies were performed using a specially developed authors’ technique. A distinctive feature of the technique is the modeling of an essential feature of corrosion processes occurring in real oilfield systems in the presence of carbon dioxide – a high rate of local corrosion exceeding the corrosion rate by 2–9 times. The standard environment and conditions of laboratory experiments used in laboratory tests make it possible to reproduce local corrosion damage visible and measured using a needle micrometer (> 0.01 mm) on corrosion control samples by the weight method. It is shown that the protective effect of the corrosion inhibitor VITERASOYUZ-2000 of the BP-2 brand in relation to local corrosion is achieved at a dosage of 100–150 mg/dm3.The practical significance of the research is shown by a retrospective analysis of data from weight (gravimetric) corrosion monitoring during industrial testing of corrosion inhibitors, which confirm that the use of «traditional» dosages of 15–40 mg/dm3 (based on the total volume of liquid = oil + water) with a high protective effect against corrosion consumption («general corrosion») do not provide a protective effect against local corrosion. It is noted that in some cases, corrosion inhibitors, due to reducing corrosion consumption, can not help only reduce the rate of local corrosion, but, on the contrary, stimulate its development. The target of the tests is to increase the reliability of pipeline operation and environmental safety while reducing the increase in accidents and the number of failures.

Geodetic monitoring of technical conditions of flowlines located on agricultural lands

The article analyses the use of various devices in monitoring flowlines passing through agricultural lands for preserving the ecological well-being of arable lands during the operation of such pipelines. The monitoring includes an important stage of searching for the pipe and determining the depth of its occurrence. The experience of conducting such search operations indicates the presence of problems in this area. The authors present the results of a comparative analysis of determining the depth of laying the pipes of various diameters using a pipeline locator and a search probe. The authors also describe the sequence of research activities and give some recommendations on the use of the most effective methods to ensure quality, save time and keep environmental well-being during pipeline operation.

The reliability of pre-deformation to control lateral buckling of pipelines: An evaluation based on observed embedment trends

Pre-deformation of a pipeline into a continuous sinusoidal wave-like form has been shown to be effective at controlling lateral buckling of subsea pipelines due to a substantially lower axial stiffness and the limiting of maximum strain at any location. This paper explores the feasibility and reliability of using such an approach, with an existing operating pipeline, which was installed using zero-radius bend (ZRB) initiator structures, used for comparison. Survey data of the pipeline profile and seabed bathymetry are adopted along with the pipe-soil interaction (PSI) inputs from the original design allowing a like-for-like comparison of the two approaches to management of lateral buckling. The comparison shows that, for the assumptions made in the numerical modelling, use of a pre-deformed pipeline results in lower strain than using ZRBs. Furthermore, the performance of the pre-deformed pipeline is robust, and shown to be unaffected by uncertainties in horizontal out-of-straightness, PSI input and seabed features. This study shows that pre-deformed pipelines can be an effective alternative for controlling the lateral buckling of subsea pipelines, which eliminates the need for buckle initiation structures to be installed along the pipeline route. This provides impetus for further work on installation methodologies to create the required level of pre-deformation.

DeepPipe: A multi-stage knowledge-enhanced physics-informed neural network for hydraulic transient simulation of multi-product pipeline

In the chemical pipelining industry, owing to the high-pressure transportation process, an accurate hydraulic transient simulation tool plays a central role in preventing the slack line flow and overpressure from causing pipeline operation treacherous. Nevertheless, the current model-driven method often faces challenges in balancing computational efficiency with accuracy, and the existing data-driven models struggle to produce explainable results from the physics perspectives since insufficient theoretical principles are incorporated into the model training. Additionally, the existing physics-informed learning architecture fails to achieve a gradient-balanced training, resulting from the significant magnitude difference in outputs and multiple loss terms. Consequently, a Multi-Stage Knowledge-Enhanced Physics-Informed Neural Network (MS-KE-PINN) is proposed for the hydraulic transient simulation of multi-product pipelines. To enforce the neural network producing simulation results with high consistency to physical laws, the governing equations, boundary, and initial condition are incorporated into the training process for an efficient mesh-free simulation. Then, considering that the significant magnitude difference between outputs can easily lead to deficient performance in the gradient descent, the magnitude conversion on the outputs and the equivalent conversion of the governing equations are implemented to enhance the training effect of the neural network. Subsequently, to tackle the imbalanced gradient of multiple loss terms with fixed weights, a multi-stage hierarchical training strategy is designed to improve the approximation capacity of the neural network. Numerical simulation cases demonstrate a better approximation function of the proposed model than the state-of-art models, while the mean absolute percentage errors yielded by MS-KE-PINN are reduced by 77.4 %, 88.7 %, and 87.8 % in three simulation operation conditions for pressure prediction. Furthermore, experimental investigations from a real-world multi-product pipeline suggest that the proposed model can still draw accurate simulation results even under complex and dynamic hydraulic transient scenarios in practice, with root mean squared errors reduced by 94.8 % and 80 % than that of the physics-informed neural network. To this end, the proposed model can conduct accurate and effective hydraulic transient analysis, thus ensuring the safe operation of the pipeline.

Water Supply Pipeline Operation Anomaly Mining and Spatiotemporal Correlation Study

Water Supply Pipeline Operation Anomaly Mining and Spatiotemporal Correlation Study

A rapid method for composition tracking in hydrogen-blended pipeline using Fourier neural operator

Blending hydrogen into natural gas for transportation is a crucial approach for achieving the widespread utilization of hydrogen. Tracking the concentration of the hydrogen within the pipeline is important for monitoring gas quality and managing pipeline operations. This study develops a rapid computational model to predict the hydrogen and natural gas concentrations within the pipeline during transportation based on the Fourier Neural Operator (FNO), an operator neural network capable of learning the differential operator in the partial differential equation. In the proposed model, the numerical method is employed to generate datasets, with the spline interpolation used to enhance data smoothness. The initial and boundary conditions are taken as the inputs to accommodate varying transportation scenarios. Comparison results indicate that the proposed model can notably reduce the time needed to predict the hydrogen and natural gas concentrations while maintaining prediction accuracy. The accuracy of the proposed model is validated by comparing its calculated results with the analytical solution and the concentrations of hydrogen and natural gas within the pipeline under two transportation scenarios, with relative errors of 0.49%, 0.31%, and 0.45%, respectively. Notably, the trained model demonstrates strong grid invariance, a type of model generalization. Trained on data generated from a coarse grid of 101 × 41 spatial-temporal resolution, the proposed model can accurately predict results on a fine grid of 401 × 81 spatial-temporal resolution with a relative error of only 0.38%. Regarding the prediction efficiency, the proposed model achieves an average 17.7-fold speedup compared to the numerical method. The positive results indicate that the proposed model can serve as a rapid and accurate solver for the composition transport equation.

Precision and uncertainty in natural gas calorific value estimation: advanced combinatorial predictive models for complex pipeline systems

Abstract In recent years, natural gas pipelines have been characterized by multiple intake points, the mixing of different gas sources, and significant variations in gas quality. The existing volumetric measurement system is no longer suitable for the development and operation of natural gas pipelines in China. To ensure accurate and equitable implementation of natural gas measurement, there is a gradual shift towards energy measurement. However, due to numerous measurement interfaces, installing chromatographs at all measurement stations would lead to substantial investment costs. Therefore, predicting the calorific value of natural gas is a key technology for energy measurement. In view of the issues existing in the current methods of obtaining natural gas calorific value, different prediction models of natural gas calorific value are constructed. According to the influencing factors of natural gas calorific value, the uncertainty evaluation is carried out, and the accuracy of different calorific value prediction models is analyzed by case data. The maximum error of regression equation, response surface analysis, BP neural network and genetic algorithm prediction model is 2.29%, 0.43%, 0.59% and 0.45% respectively. However, the combined calorific value (CCV) prediction model is 0.41%. The results indicate that the predicted value calculated by the CCV prediction model is closer to the actual value and has higher prediction performance, which provides a new method for the calorific value prediction and measurement management of natural gas.

Real-Time Analysis and Digital Twin Modeling for CFD-Based Air Valve Control During Filling Procedures

Air exchange in pressurized water pipelines is an essential but complex aspect of pipeline modeling and operation. Implementing effective air management strategies can yield numerous benefits, enhancing the system’s energy efficiency, reliability, and safety. This paper comprehensively evaluates an irregular profile pipeline filling procedure involving air-release through an air valve. The analysis includes real-time data tests and numerical simulations using Computational Fluid Dynamics (CFD). A Digital Twin model was proposed and applied to filling maneuvers in water installations. In particular, this research considers an often-overlooked aspect, such as filling a pipe with an irregular profile rather than a simple straight pipe. CFD simulations have proven to capture the main features of the transient event, which are suitable for tracking the air-water interface, the unsteady water flow, and the evolution of the trapped air pocket. Thus, they provide thorough and reliable information for real-time operational processes in the industry, focusing on the filling pressure and geometry of the air-valve hydraulic system. Additionally, this study provides details regarding the application of an efficient Digital Twin CFD approach, demonstrating its feasibility in optimizing the filling procedure in pipes with irregular profiles.

Exploring NRB Biofilm Adhesion and Biocorrosion in Oil/Water Recovery Operations Within Pipelines.

Microbially influenced corrosion represents a critical challenge to the integrity and durability of carbon steel infrastructure, particularly in environments conducive to biofilm formation by nitrate-reducing bacteria (NRB). This study investigated the impact of NRB biofilms on biocorrosion processes within oil/water recovery operations in Algerian pipelines. A comprehensive suite of experimental and analytical techniques, including microbial analysis, gravimetric methods, and surface characterization, were employed to elucidate the mechanisms of microbially influenced corrosion (MIC). Weight loss measurements revealed that carbon steel samples exposed to injection water exhibited a corrosion rate of 0.0125 mm/year, significantly higher than the 0.0042 mm/year observed in crude oil environments. The microbial analysis demonstrated that injection water harbored an average of (4.4 ± 0.56) × 106 cells/cm2 for sessile cells and (3.1 ± 0.25) × 105 CFU/mL for planktonic cells, in stark contrast to crude oil, which contained only (2.4 ± 0.34) × 103 cells/cm2 for sessile cells and (4.5 ± 0.12) × 102 CFU/mL for planktonic cells, thereby highlighting the predominant role of injection water in facilitating biofilm formation. Contact angle measurements of injection water on carbon showed 45° ± 2°, compared to 85° ± 4° for crude oil, suggesting an increased hydrophilicity associated with enhanced biofilm adhesion. Scanning electron microscopy further confirmed the presence of thick biofilm clusters and corrosion pits on carbon steel exposed to injection water, while minimal biofilm and corrosion were observed in the crude oil samples.

Comparing green hydrogen and green ammonia as energy carriers in utility-scale transport and subsurface storage

Many of the challenges associated with utility-scale hydrogen transport and storage relate to its low density, high diffusivity, and the risk of hydrogen embrittlement, motivating consideration to integrating ammonia as an energy carrier. Compared to hydrogen, ammonia is more compatible with pipeline materials and delivers energy at higher density. Ammonia is also a mature industry with a greater extent of established pipeline networks and regulations that may accelerate hydrogen transitions and penetration in energy grids. However, converting hydrogen produced by renewable-driven electrolysis into ammonia (and back to hydrogen, depending on end use) complicates logistics, and associated energy and resource demands may offset the green hydrogen's carbon neutrality. This work outlines core considerations for the use of hydrogen vs. ammonia during transport and storage operations, with an emphasis on green hydrogen or green ammonia pathways coupled to pipeline transport and underground storage. We compare tradeoffs in pipeline infrastructure and operations; subsurface storage options; and project economics. We also evaluate round-trip efficiencies (RTE) for both pathways, which indicate that hydrogen is more attractive from an energy efficiency perspective for hydrogen end-use applications due to the efficiency penalties of initial ammonia synthesis and subsequent cracking, but RTE's for ammonia transport and storage are comparable to hydrogen for direct use or ammonia-to-power systems. The tradeoffs presented in this work would need to be considered on a case-by-case basis, but indicate that selective use of ammonia as an energy-dense hydrogen carrier could support decarbonization goals in industry and hydrogen economies.

Hydrate formation and its influence on natural gas pipeline: Simulation study

Natural gas transportation is plagued with the twin problem of hydrate and corrosion that occurs when a hydrate prone gas is conveyed in such a manner that the pipeline operating conditions fall within hydrate formation region of the hydrate phase envelop. This study simultaneously studied this twin problem, establishing their interdependent using gas sample from Niger Delta that was meticulously simulated and analysed for hydrate formation possibilities with the aid of Unism software. CO2 corrosion was simulated using NORSOK M-506 standard model in matlab. Major factors considered are the relationship between corrosion rate and temperature, corrosion rate and PH, corrosion-temperature relationship for varying CO2 mole percent, and PH values. The result from this study established that both type I and type II hydrates could form at the operating conditions of 5OC and 60 bar. Rate of corrosion decreases and increases with increase in PH and temperature respectively to a certain temperature of approximately 78 OC, then a dip in rate of corrosion. Corrosion-temperature relationship for varying PH and CO2 mole percent shows a decrease in corrosion rate with an in increase in PH, and an increase with increase in CO2 mole percent, with a rise as high as 5,7 mm/year at a 3 mole percent. This value and trend portray a bad omen for the affected pipeline. This study recommends that natural gas to be transported by pipeline should be sweetened and processed to remove H2S, CO2 and mercaptans if present and also to satisfy maximum dew point specification.

Study on water hammer phase transition characteristics of dense/liquid phase CO2 pipeline

Under water hammer conditions, dense/liquid phase CO2 pipelines are prone to enter the phase equilibrium zone due to significant pressure fluctuations, further disrupting flow stability. At present, the research on the sudden changes in physical properties and pressure wave transmission characteristics caused by CO2 phase transition during water hammer transient process is not clear. This article uses experiments to screen the state equation suitable for CO2 phase characteristic calculation. Based on this, the characteristic line method is used to solve the one-dimensional pipeline water hammer flow process. When the water hammer pressure is lower than the saturation pressure, the corresponding gas phase fraction is solved using the isentropic principle. The results indicate that a phase transition occurs under water hammer conditions when the operating temperature is 280–300 K and the operating pressure is 0.59 %–4.55 % higher than the saturation pressure. When a phase transition occurs, for the valve front, 1.33 % gas generation will increase the pressure wave velocity by 1.67 %, and for the valve rear, 0.86 % gas generation will increase the pressure wave velocity by 0.61 %. This study provides a basis for the safe and stable operation of CO2 pipelines.

Anions exacerbate microbial corrosion of X80 pipeline steel induced by sulfate-reducing bacteria in the sea mud environment

Sulfate-reducing bacteria (SRB) present in sea mud pose a challenge to the safe operation of subsea pipelines. Chlorides and sulfates in sea mud promote the microbial corrosion of subsea pipelines by SRB. This study investigates the effects of sulfate and chloride on the microbial corrosion of X80 pipeline steel in the sea mud environment. The results indicate that sulfate serves as an electron acceptor, promoting the growth of SRB, while chloride regulates the osmotic pressure of SRB cells, affecting their bioactivity. SRB exhibit more aggressive corrosion behavior in sea mud with high concentrations of both chloride and sulfate.

Dynamic fluid flow model for phosphate slurry pipeline: OCP main pipeline as case study

The transportation of phosphate slurry through large-scale pipelines presents significant challenges due to the complex behavior of multiphase flows, particularly with varying solid content, density, and dynamic viscosity. Efficient and accurate prediction of flow behavior is critical for optimizing the operation of such pipelines. This work aims to develop a dynamic computational model to simulate phosphate slurry flow in pipelines. The case study focuses on the OCP Group’s main slurry pipeline, which links the mining sites at Khouribga to the industrial plants at Jorf Lasfar, Morocco. This pipeline system spans a total length of 187.124 km, consisting of 5237 pipes with an inner diameter ranging from 0.8546 m to 0.8578 m, and features several elevation changes along its ground level. Using a section-averaged, dynamic approach and the Finite Volume scheme, the model computes essential flow parameters, including density, dynamic viscosity, and pressure, for the incompressible and non-Newtonian slurry and process water flows. The model’s accuracy is validated against on-site measured data, showing an average deviation of ±0.32% for outlet density, and below 10% for pressure along the pipeline, underscoring the model’s reliability. Additionally, a sensitivity analysis was conducted to illustrate the impact of key parameters on the predicted head losses and pressures along the pipeline. This analysis shows that the slurry viscosity is the most critical parameter, significantly influencing these predictions. This model provides high accuracy and reasonable CPU time for real-time simulation and monitoring, while also offering significant potential for optimizing pipeline operations and ensuring the reliability of phosphate transport.