•Bayesian network model for buried gas pipeline failure analysis is presented.•The pipeline failure caused by corrosion and external interference is analyzed.•Failure frequency and leakage size are ...analyzed based on pipeline characteristics.•The pipeline in the city of Hefei is used to state the practicability of the model.•Critical pipeline parameters can be identified using this model.
The unintentional release of urban buried gas pipeline may cause crucial consequences to the economy, society and environment. Corrosion and external interference are primary causes of pipeline failure incidents. Due to the complexity and unpredictability of outside influence on the buried gas pipeline, this paper presents an approach to analyze pipeline failure frequency and leakage size caused by corrosion and external interference based on pipeline characteristics. Bayesian network method is used to construct a knowledge model. Pipeline characteristics statistics and failure data are collected to build the relationships among variables in the model and verify the applicability of the model. Results show that the proposed model can estimate buried gas pipeline failure frequency and leakage size caused by corrosion and external interference. It is also capable of highlighting the critical parameters to pipeline failure. Practical application of the model is demonstrated on the underground gas pipeline in the City of H, China. Results indicate that proposed model can explicitly quantify uncertainties and then put forward practical measures for buried gas pipeline parameter design, laying plan and operating maintenance.
Pipelines are widely used in transporting large quantities of oil and gas products over long distances due to their safety, efficiency and low cost. Integrity is essential for reliable pipeline ...operations, for preventing expensive downtime and failures resulting in leaking or spilling oil or gas content to the environment. Pipeline integrity management is a program that manages methods, tools and activities for assessing the health conditions of pipelines and scheduling inspection and maintenance activities to reduce the risks and costs. A pipeline integrity management program mainly consists of three major steps: defect detection and identification, defect growth prediction, and risk-based management. In-line inspections (ILI) are performed periodically using smart pigging tools to detect pipeline defects such as corrosion and cracks. Significant advances are needed to accurately evaluate defects based on ILI data, predict defect growth and optimize integrity activities to prevent pipeline failures, and pipeline integrity management has drawn extensive and growing research interests. This paper provides a comprehensive review on pipeline integrity management based on ILI data. Signal processing methods for defect evaluation for different types of ILI tools are presented. Physics-based models and data-driven methods for predicting defect growth for pipelines with different categories of defects are discussed. And models and methods for risk-based integrity management are reviewed in this paper. Current research challenges and possible future research trends in pipeline integrity management are also discussed.
•Integrity is essential for reliable pipeline operations•In-line inspections (ILI) are performed periodically using smart pigging tools to detect pipeline defects•Three major steps: defect detection and identification, defect growth prediction, and risk-based management•This paper provides a comprehensive review on pipeline integrity management based on ILI data•Current research challenges and possible future research trends are also discussed
•Oil-in-water emulsions were prepared from an Indian heavy crude oil.•High frequency ultrasonic waves were utilized to prepare oil-in-water emulsions.•Several emulsion parameters were studied to ...obtain optimum values of oil, surfactant and salt concentration of the emulsion.•A relation between interfacial tension, droplet size distribution, viscosity, stability and surface tension of emulsion was investigated.
The emulsification of heavy crude oil is the most economical way to transport it through offshore pipelines. In this research article, distinct oil-in-water (o/w) emulsions were developed from an Indian heavy crude oil using 4-(1,1,3,3-tetramethylbutyl)phenyl-polyethylene glycol. Ultrasonic waves of 26kHz frequency, produced from Hielscher UP200Ht ultrasonic homogenizer, were used to disperse crude oil in water phase. The physicochemical characteristics of heavy crude oil were determined using standard methods adopted by the petroleum industries. The functional groups of the crude oil were analyzed using FTIR. Rheological behavior of crude oil and o/w emulsions were studied using Physica rheometer MC-1 model. Interfacial tension between crude oil and aqueous phase in developed emulsions were studied using a Texas-500 spinning drop tensiometer (Data-Physics, Model No: SVT 15 N). Droplet size distribution and surface tension of emulsions were analyzed using Zetasizer Nano S90 particle size analyzer and Kruss Easy Dyne tensiometer respectively. It was experimentally observed that the viscosity of developed emulsion were lower than the viscosity of neat crude, and at 60% of oil content and 2wt% of surfactant, viscosity reduction is around 83%. A tremendous decrease in pour point was also observed after emulsification, making most of the emulsions to flow even at 1°C. Moreover, most of the prepared emulsions were found to be highly stable even after 56days of storage in ambient conditions. Hence, the prepared emulsions may be transported through the offshore pipelines efficiently.
During the service life of the offshore pipelines, different failure mechanisms like external/internal sheath damage, fatigue damage, or corrosion may arise. Therefore, high operating costs need to ...be consumed to confirm the fitness of the pipeline system. This research deals with an enhanced Risk-Based Inspection (RBI) methodology to certify the integrity management of the pipeline system, a radical new way of RBI practice is introduced for analysing steel pipeline and flexible pipeline. Case studies are executed to designate and give knowledge of how the technique works in exercise with what outcomes can be discovered. The discoveries present features of uncertainties which may not have been measured when implementing the traditional RBI scheme. The scope of this research is to display that with an efficient technique of execution the RBI practice, the failures of pipeline systems can be monitored and control system to ensures the integrity of the pipeline's system.
Pipelines play an important role in the national/international transportation of natural gas, petroleum products, and other energy resources. Pipelines are set up in different environments and ...consequently suffer various damage challenges, such as environmental electrochemical reaction, welding defects, and external force damage, etc. Defects like metal loss, pitting, and cracks destroy the pipeline’s integrity and cause serious safety issues. This should be prevented before it occurs to ensure the safe operation of the pipeline. In recent years, different non-destructive testing (NDT) methods have been developed for in-line pipeline inspection. These are magnetic flux leakage (MFL) testing, ultrasonic testing (UT), electromagnetic acoustic technology (EMAT), eddy current testing (EC). Single modality or different kinds of integrated NDT system named Pipeline Inspection Gauge (PIG) or un-piggable robotic inspection systems have been developed. Moreover, data management in conjunction with historic data for condition-based pipeline maintenance becomes important as well. In this study, various inspection methods in association with non-destructive testing are investigated. The state of the art of PIGs, un-piggable robots, as well as instrumental applications, are systematically compared. Furthermore, data models and management are utilized for defect quantification, classification, failure prediction and maintenance. Finally, the challenges, problems, and development trends of pipeline inspection as well as data management are derived and discussed.
•A deep neural network (DNN) is developed for predicting failure pressure of defective pipelines.•The sample data are obtained from FEM simulations and burst experiments.•Prediction accuracy of DNN ...is far better than that of empirical formulae.•Computational efficiency of DNN is at least two orders of magnitude faster than FEM simulations.
Determining the failure pressure of defective pipelines is an important part in pipeline reliability engineering, which affects the assessment of pipelines residual service life. In this work, a fast and accurate method for predicting the failure pressure of defective pipelines using the deep learning model is developed. The calculation results of ASME-B31GM, DNV, PCORRC codes and finite element method (FEM) are compared and analyzed in detail to obtain high-quality sample data. 150 groups of validated FEM simulation data and 142 groups of burst pressure test data are selected for the training and validation of deep learning model. In the training process, influences of key model parameters of deep neural network (DNN) on the prediction accuracy are investigated. Prediction results indicate that the used deep learning model can offer high prediction accuracy. In addition, the calculation of deep learning model is accelerated by at least two orders of magnitude compared with that of FEM simulations under same calculation conditions. Finally, the influence of defect sizes on pipeline failure pressure is analyzed by the DNN. This work is expected to shed a light on efficient and accurate predictions of failure pressure of oil and gas defective pipelines.
It is common for subsea pipelines to operate at high pressures and high temperatures (HPHT) conditions. The build-up of axial force along the pipeline due to temperature and pressure differences from ...as-laid conditions coupled with the influence of the seabed soil that restricts free movement of the pipeline can result in the phenomenon called ‘lateral buckling’. The excessive lateral deformation from lateral buckling may risk safe operation of the pipeline due to local axial strains that potentially could be severe enough to cause fracture failure of welds or collapse of the pipeline. Engineered buckles may be initiated reliably during operation by using special subsea structures or lay methods which are expensive. This paper introduces and exemplifies a novel method that involves continuously deforming the pipeline prior to or during installation with prescribed radius and wavelength to control lateral buckling that could be a valuable modification of the practical design of offshore pipelines. Previous published work has shown that installation of a pipeline with such continuous deformations is feasible. The results from an example pipeline case described here show that the pipeline can be installed and operated safely at elevated temperatures without the need for other expensive buckle initiation methods.
•A novel method of using prescribed pre-deformation along subsea pipeline is proposed to control lateral buckling.•Results show that pre-deformed pipeline enables it to accommodate very high temperatures before lateral buckling initiates.•Cyclic analysis of the pre-deformed pipeline induces a form of shake-down that progressively reduced the strain levels.•Pre-deforming a pipeline for lateral buckling enables safe operation without the need of expensive buckle initiation methods.
Water pipeline leakage detection is still an important issue, particularly for the development of smart cities. Thus, this paper reviews water pipeline leakage detection techniques, which can be ...classified into three different categories, namely, software-based, hardware-based, and conventional methods. We compare the advantages and disadvantages for all the methods in the groups and thoroughly discuss the hardware-based method, which is our focus. Specifications on water pipeline testbeds used in the previous works are also highlighted. Since many recent techniques are based on accelerometer or vibration sensors, a comparative study that includes the cost and accuracy in identifying the pipeline leaks is presented. The theoretical computation of the vibration induced from our water pipeline testbed is also demonstrated and compared with the actual vibration data collected from the experimental works using three different sensors, namely, MPU6050, MMA7361, and ADXL335.
•The PIAUV and pipeline tracking system is introduced.•An optimized Rosenfeld algorithm is proposed.•The acquisition method of target point to be tracked is proposed.•The reliability of the proposed ...algorithm in real-time positioning and tracking of pipelines.•The proposed submarine pipeline tracking algorithm is feasible.
Submarine pipelines have provided an important approach to transport marine oil and gas resources because of their simplicity and efficiency. However, natural or man-made causes can easily lead to pipeline damage and thus result in waste of resources and environmental pollution. At present, the manual routine inspection of submarine pipelines is mainly completed by the survey vessels, which requires a large workload and high cost. The use of autonomous underwater vehicles with multibeam sonar system for real-time surveys is a good solution to this problem. Yet, the accumulation of errors in the integrated navigation system of the vehicle over a long period of operation can cause relatively large position deviations, since the signals of global positioning system cannot be received in the deep sea. To deal with it, the forward looking sonar is adopted in this study to obtain the precise position of the submarine pipeline and a tracking algorithm is proposed to track it. Firstly, the software development kit of the forward looking sonar is used to continuously obtain the pseudo-color images of the submarine pipeline, which are converted into 8-channel gray-scale images for image segmentation and binarization. Secondly, the optimized Rosenfeld algorithm is applied to thin the binary images, after which the submarine pipeline is identified and the corresponding function is fitted to determine the location of the target point to be tracked. Finally, the geodetic coordinates of the target point are determined through coordinate conversion to position the submarine pipeline. A sea trial is carried out and the results prove that accurate and stable pipeline tracking can be achieved by combining the integrated navigation system and the proposed algorithm.
•This paper proposes a novel approach to crack detection and localization in a pipeline.•The proposed method scans peaks in the individual signal channels in the time-frequency domain.•Aadjacent ...events are picked and paired together on two sensor channels to localize emission sources.•Rayleigh wave velocity is calibrated by a pencil lead breaking procedure.•Finally, the approach observes their distribution according to the position and time of occurrence.
This paper introduces a novel approach to crack detection and localization in a pipeline transporting fluid under high pressure. From acoustic emission signals acquired by two R15i-AST sensors at two ends of a fluid pipeline, the proposed method scans peaks in the individual signal channels in the time-frequency domain and filters out noise to obtain acoustic emission events. Subsequently, adjacent events are combined into grouped events, and these are picked and paired together on two sensor channels to localize emission sources using the time difference of arrival technique. To improve the location accuracy, the mechanism only determines the arrival time of Rayleigh waves with a similar frequency in event pairs. Furthermore, the Rayleigh wave velocity is calibrated by a pencil lead breaking procedure. Additionally, false emission sources are eliminated by considering the wave energy attenuation characteristics in their propagation path. After locating the emission sources, the approach observes their distribution according to the position and time of occurrence. The variation in acoustic emission activity against applied load, which is established by counting the returned sources, can indicate irregular structural changes in a material. The location of the structural change can be surmised by the emission source distribution and density according to the position along the pipeline. Experimental results show that the proposed method correctly diagnoses faults in the considered pipeline from acoustic emission signals, whereas a conventional approach (performed by detecting hits with a threshold) inaccurately localizes acoustic emission sources and imprecisely exposes signs of abnormal structural transformations.
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