Investigating the Effectiveness of Techniques Used in Assessing the Integrity of Non-Piggable Pipelines

2004 ◽  
Author(s):  
Giorgio G. J. Achterbosch ◽  
Gerard A. J. Stallenberg
Keyword(s):  
Detection Threshold ◽  
Metal Loss ◽  
Substantial Part ◽  
Valuable Insight ◽  
Specific Situation ◽  
General Corrosion ◽  
Survey Techniques ◽  
Detection Probabilities ◽  
The Sixties ◽  
Coating Defect

A substantial part of the high pressure gastransport network of Gastransport Services as part of N.V. Nederlandse Gasunie in the Netherlands is not piggable. It is therefore foreseen that an ECDA approach including coating survey techniques, CP measurements and bell hole excavations, will be implemented to establish the integrity of these non-piggable lines. In order to get a better understanding of the performance of some techniques for our specific situation, a test program was carried out on a pipeline of 33 kilometres with a diameter of 8” and bitumenous coating, constructed in the sixties. DCVG, Pearson and a combination of CIPS and Pearson (CIPP) were tested in combination with 3 MFL intelligent pigruns, current attenuation measurements by the Stray Current Mapper (SCM) and bell hole excavations. Initial results for the three coating survey techniques showed that the detection probabilities for a coating defect ranged from 18% to 68% under the assumption that no false calls were generated. Using results from repeat measurements and taking into account the possibility of false calls, the detection probabilities increased to potential maximum values of 48% to 94%. Better estimations of the values could be obtained after verification of some indications from CIPP, leading to maximum values in the range of 70% to 84% for the best two techniques. Additional measurements at pre-selected locations by means of pipe-to-soil-potentials and pin-current measurements did not indicate active corrosion. Verification excavations at 14 locations indicated that in all situations a coating defect existed and that mild general corrosion was present in eight situations due to the very aggressive soil (soil resistances of several Ωm’s were measured). Current attenuation measurements by the SCM suggested a uniform distribution of coating quality. The results from the three intelligent pigruns were of relatively little use because of the detection threshold of 15% wall thickness and the fact that the suppliers often did not agree on the interpretation of metal loss. Therefore the results could not be considered to be an absolute true reference for relating the coating defects to. Although the results of the program gave very valuable insight into the characteristics of the different techniques it is recognized that not all results can be translated to other circumstances/pipelines. Therefore additional tests and surveys will be carried out in the coming year(s) to further work out the ECDA procedure for the specific situation of the non-piggable pipelines of Gastransport Services.

Remaining Local Buckling Resistance of Corroded Pipelines

2010 ◽  
Author(s):  
Qishi Chen ◽  
Heng Aik Khoo ◽  
Roger Cheng ◽  
Joe Zhou
Keyword(s):  
Finite Element ◽  
Wall Thickness ◽  
Phase 1 ◽  
Compressive Strain ◽  
Research Work ◽  
Local Buckling ◽  
Model Verification ◽  
Metal Loss ◽  
General Corrosion ◽  
Buckling Resistance

This paper describes a multi-year PRCI research program that investigated the local buckling (or wrinkling) of onshore pipelines with metal-loss corrosion. The dependence of local buckling resistance on wall thickness suggests that metal-loss defects will considerably reduce such resistance. Due to the lack of experimental data, overly conservative assumptions such as a uniform wall thickness reduction over the entire pipe circumference based on the defect depth have been used in practice. The objective of this research work was to develop local buckling criteria for pipelines with corrosion defects. The work related to local buckling was carried out in three phases by C-FER and the University of Alberta. The first phase included a comprehensive finite element analysis to evaluate the influence of various corrosion defect features and to rank key parameters. Based on the outcome of Phase 1 work, a test matrix was developed and ten full-scale tests were carried out in Phase 2 to collect data for model verification. In Phase 3, over 150 parametric cases were analyzed using finite element models to develop assessment criteria for maximum moment and compressive strain limit. Each criterion includes a set of partial safety factors that were calibrated to meet target reliabilities selected based on recent research related to pipeline code development. The proposed criteria were applied to in-service pipeline examples with general corrosion features to estimate the remaining load-carrying capacity and to assess the conservatism of current practice.

Fitness for Service Assessment of Cross Country Oil Pipelines Based on API 579 (Application of API 579 on ASME B 31.4)

2019 ◽  
Author(s):  
Pradeep Purnana ◽  
Shiyas Ibrahim
Keyword(s):  
Oil And Gas ◽  
Internal Surface ◽  
Life Assessment ◽  
Metal Loss ◽  
Complex Method ◽  
General Corrosion ◽  
Loss Assessment ◽  
Oil Pipelines ◽  
Corrosion Defects ◽  
Cross Country

Pipelines are one of the safest forms of transportation for oil and gas. However, Pipelines may experience defects, such as corrosion, cracks during service period. Therefore, evaluation of these defects is very important in terms of assessment and for continued safe operation. Corrosion defects at the external surface of pipelines are often the result of fabrication faults, coating or cathodic protection issues, residual stress, cyclic loading, temperature or local environment (soil chemistry). In general, corrosion may occur in most pipes due to coating failure, and a pipe without any protective coating will experience external corrosion after some years. However, corrosion can occur on the internal surface of the pipeline due to contaminants in the products such as small sand particles. At present, there are different assessment methods for different types of defects in pipelines. The most popular codes for defect assessment in oil and gas pipelines are RSTRENG, Modified B31G, BS 7910 and API 579. Besides these codes and methods, there are numerical programs, such as CorLAS, which have been used successfully for assessing crack flaws in Pipelines. RSTRENG and B 31G methods are very simple when compared with API 579. API 579 is very complex method of assessing defects but very useful for remaining life assessment of Pipelines. In this paper corrosion defects like general metal loss, localized metal loss, pitting corrosion, other defects like dents, gouges, cracks, their remediation methods assessed based on API 579 method and our experience in Oil Pipelines. Since API 579 doesn’t cover cross country pipelines explicitly, we have made a research applying API 579 to ASME B31.4. Even though, we have done research on all types of defects (Level 1 and Level 2 assessment), in this paper we have covered only General metal loss assessment.

Assessing detection probabilities for the endangered growling grass frog (Litoria raniformis) in southern Victoria

2006 ◽  
Vol 33 (7) ◽  
pp. 557 ◽  
Author(s):  
Geoffrey W. Heard ◽  
Peter Robertson ◽  
Michael P. Scroggie
Keyword(s):  
Data Analysis ◽  
Survey Data ◽  
Credible Interval ◽  
Single Site ◽  
Species Occurrence ◽  
Survey Techniques ◽  
Site Survey ◽  
Detection Probabilities

Assessment of the efficacy of survey techniques for determining species occurrence is crucial for the validation of wildlife survey data. We analysed repeated site-survey data for adults and larvae of the growling grass frog (Litoria raniformis) in order to estimate probabilities of detection for the species using alternative survey techniques. The estimated probability of detecting adults of L. raniformis at occupied sites using diurnal searches was much less than 1.0 (0.107; 95% credible interval: 0.045, 0.192). The estimated probability of detecting adults using nocturnal spotlight searches was considerably higher, but still less than 1.0 (0.696; 95% credible interval: 0.585, 0.796). These results indicate that nocturnal searches are a much more efficient and reliable means of detecting the presence of adult L. raniformis than diurnal searches, but detection using either technique is less than certain. The probability of detecting tadpoles of L. raniformis using either funnel-trapping or dip-netting techniques was estimated at 0.350 (95% credible interval: 0.151, 0.567). Together, these results indicate that reliance on single-site visits during surveys for this species is likely to result in severe under-estimation of the proportion of sites that are actually occupied. We urge other workers to use repeated site-survey data and appropriate methods of data analysis to assess and report probabilities of detection when documenting the results of wildlife surveys.

Historical Rates of Soil Side Corrosion for Use in Fitness-for-Service Evaluations of Buried Metallic Pipe

2016 ◽  
Author(s):  
Douglas Munson ◽  
Mahesh Pandey ◽  
Mikko Jyrkama ◽  
Peter Angell
Keyword(s):  
Soil Texture ◽  
Nuclear Power ◽  
Power Plants ◽  
Historical Data ◽  
Localized Corrosion ◽  
Metal Loss ◽  
National Bureau ◽  
General Corrosion ◽  
Corrosion Rates ◽  
Maximum Penetration

Nuclear power plants and many other industries are required to periodically inspect their buried piping to determine its fitness-for-continued service (FFS). The FFS process requires that both the general corrosion rate and the rate of maximum penetration for localized corrosion (e.g., pitting) be estimated so that the remaining lifetime and/or time until the next inspection can be determined. Revision 1 to ASME Code Case N-806, “Evaluation of Metal Loss in Class 2 and 3 Metallic Piping Buried in a Back-Filled Trench” [1] provides 4 options for estimating the corrosion rates: a. Wall thickness measurements from the current examination and from one or more previous examinations of the same metal loss region. b. Repeat measurements at two or more times from another location that has a predicted metal loss rate greater than or equal to the rate of the metal loss region under evaluation. c. Repeat measurements using corrosion coupons, linear polarization probes, or electrical resistance probes d. Generic historical data Each of these methods has its uses and limitations, and it is generally preferable to consider results from 2 or more of the methods. This paper examines historical data gathered by the National Bureau of Standards (NBS, renamed in 1988 as the National Institute of Standards & Technology - NIST) at ∼ 70 locations around the US in the 1930s – 1950s. Maximum penetration and weight loss (general corrosion) data from each site were placed in one of four soil texture groups for both carbon steel and cast iron. A regression analysis was performed to determine the median rates and 80% and 95% probabilistic values. It was found that results within each soil texture group were relatively similar and that the corrosion rates in the first 3 years after burial tended to be much higher than rates in years 5–18. The coefficients of determination were determined to quantify differences within each soil texture group. It is proposed that the steady state rates provided herein are an option to be used as the Historical Rates for FFS evaluations as described in [1].

ILI to ILI Comparisons: Quantifying the Impact of Multiple Inspections

2016 ◽  
Author(s):  
Pamela J. Moreno ◽  
Matthew A. Ellinger ◽  
Thomas A. Bubenik
Keyword(s):  
Wall Thickness ◽  
Magnetic Flux Leakage ◽  
Metal Loss ◽  
Data Sets ◽  
General Corrosion ◽  
Pipeline Segment ◽  
One To One ◽  
Pipe Geometry ◽  
The Impact ◽  
Flux Leakage

Det Norske Veritas (U.S.A.), Inc. (DNV GL) prepared this paper in order to study the repeatability of inspection results between subsequent in-line inspections. DNV GL has access to a significant amount of data that spans many different pipeline operators, ILI vendors, inspection years, and inspection technologies. DNV GL is well suited to complete this study as a result of our access to these various data sets. Over 55,000 one-to-one metal loss defect comparisons were assembled from ILI-to-ILI analyses. Reported metal loss defect depths, lengths, and widths spanning from 2003 through 2015 from 13 pipeline operators and 36 pipeline segments were compiled to meet the objectives of this paper. Inspection technologies include axial magnetic flux leakage (MFL), ultrasonic wall thickness (UTWT), spiral MFL, and circumferential MFL ILI. From analyses of these data, the following conclusions were generated: • Effect of ILI vendor: ILI repeatability is generally improved when the same ILI vendor is used (when compared to using two different ILI vendors in subsequent inspections), but this is not always true. • Reported metal loss depths: ILI repeatability decreases with increasing metal loss depth. • Pipe geometry and type: ILI repeatability is better in larger diameter pipelines and with increasing wall thickness. • POF classification: ILI repeatability is better for pitting, general corrosion, and axial grooving defects as compared to the other POF classifications. Based on these insights, the authors make the following recommendations: • Pipeline operators should consider using the same ILI vendor and tool if the goal is to identify change and/or corrosion growth in the pipeline segment. A raw signal review is encouraged in order to verify the presence, or lack thereof, changes in metal loss morphologies. The raw data review is especially important when comparing inspections from two different ILI vendors. • If the goal is to identify corrosion growth, and a pipeline operator uses different ILI vendors, it is recommended that a statistical review of one-to-one matched metal loss features take place to identify candidate locations that are more likely to be growing. The candidate locations should have a raw signal review in order to verify whether or not growth is taking place.

New Procedures for the Residual Strength Assessment of Corroded Pipe Subjected to Combined Loads

1996 ◽  
Author(s):  
Marina Q. Smith ◽  
Stephen C. Grigory
Keyword(s):  
Finite Element ◽  
Failure Criterion ◽  
Failure Modes ◽  
Model Development ◽  
Metal Loss ◽  
General Corrosion ◽  
Moment Capacity ◽  
Strength Assessment ◽  
Global Buckling ◽  
Buckling Failure

Motivated by the inability to accurately address non-pressure related stresses within the framework of current assessment guidelines, a three phase study aimed at the progressive development of a reliable and readily-useable procedure suitable for the analysis of internally pressurized degraded pipes which sustain large settlement and/or axial loads was performed. To ensure accuracy of the resulting procedure, full-scale experiments and finite element numerical simulations of artificially corroded 48-inch (122-cm) diameter X65 pipes subjected to combined loadings were designed to produce upper and lower bound rupture and global buckling failure envelopes for a given set of representative corrosion dimensions. The evaluation model accommodates combined stresses arising from internal pressure, axial bending, and axially compressive loadings to predict operational margins of safety for a pipe containing discrete or multiple metal loss regions guided by failure criteria which considers two critical failure modes: 1) a von Mises type failure criterion for rupture moment capacity determination, and 2) a global buckling failure criterion for identification of the critical moment capacity approximating collapse of the pipe mid-section due to a reduction in bending stiffness attributed in part to ovalization of the cross-section. The new methodology has been incorporated in the personal computer based program SAFE (Shell Analysis Failure Envelope), developed by Southwest Research Institute (SwRI) for the Alyeska Pipeline Service Company. The user-friendly program allows for definition of combined applied stresses and geometry of the degraded region through implementation of field-obtainable pre-or post-excavation measurements, and employs unique features which provide for the examination of pipe sections exhibiting distinct areas of general corrosion, or “patches,” separated both longitudinally and circumferentially, in a single analysis run. This paper outlines the model development and validation with supporting experiments and numerical analyses, and extension of the new procedure through sophisticated numerical techniques embodied in SAFE to actual corrosion profiles and service loadings. Detailed information included in the review are the finite element and SAFE program failure predictions for pipes analyzed with a given set of corrosion dimensions and load magnitudes, and a thorough discussion of the practical application of the SAFE program.

Lev Kuleshov on Animation: Montaging the Image

Animation ◽  
2017 ◽  
Vol 12 (2) ◽  
pp. 110-122
Author(s):  
Olga Blackledge
Keyword(s):  
Soviet Union ◽  
Substantial Part ◽  
Specific Situation ◽  
State Archive ◽  
Production Characteristic ◽  
Soviet Film ◽  
The Soviet Union ◽  
Russian State ◽  
Primary Focus

The Soviet film director Lev Kuleshov has not been historically associated with animation, and yet his legacy includes: an article on animation published in the Soviet central specialized newspaper Kino Gazeta; a film, a substantial part of which is animated; as well as a text of four lectures preserved in the Russian State Archive of Literature and Art (RGALI). In the lectures that he delivered to animators at the Soviet central animation studio Soiuzmul’tfil’m, he repurposes his theories of montage and acting for the needs of the medium of animation. Analyzing these materials, with the primary focus on the lectures, this article introduces Kuleshov’s contribution to animation theory and production, and suggests that Kuleshov’s legacy not only sheds light on the historically specific situation in animation production characteristic for the Soviet Union in the 1930s, but also facilitates a deeper understanding of the animated image as a phenomenon.

scholarly journals Microstructure Refinement on Crevice Corrosion of High-Speed Rail Steel U75V Visualized by an In Situ Monitoring System

2022 ◽  
Vol 8 ◽  
Author(s):  
Jian Wang ◽  
Binbin Zhang ◽  
Weichen Xu ◽  
Jie Zhang ◽  
Lihui Yang ◽  
...  
Keyword(s):  
Crevice Corrosion ◽  
High Speed ◽  
Rail Steel ◽  
In Situ Monitoring ◽  
Metal Loss ◽  
General Corrosion ◽  
High Speed Rail ◽  
Cooling Rates ◽  
Microstructure Refinement

Rail foot covered by a fastener will suffer from crevice corrosion, leading to thinning and localized attack of crevice interior posing a risk of failure. This work investigated crevice corrosion behavior of a typical pearlitic high-speed rail steel U75V, focusing for the first time on the effect of pearlitic microstructure refinement achieved by heat treatment with different cooling rates 2, 5, and 10°C/s. Under anodic polarization, localized dissolved spots presented on the as-received sample, where crevice corrosion mostly initiated from. For cooling rates 2 and 5°C/s, localized dissolved spots were also observed but crevice corrosion was mostly presented as general corrosion instead of from local spots, ascribed to enhanced tendency of uniform dissolution due to microstructure refinement and homogenization. For cooling rate 10°C/s, crevice corrosion expanded flocculently, ascribed to preferential dissolution of pearlitic nodules with entangled cementite due to over refinement. Crevice corrosion was obviously accelerated by microstructure refinement. Cooling rates 5 and 10°C/s led to the fastest and slowest expansion of the corroded area, respectively, while the corrosion depth was just the opposite based on the same amount of metal loss. This work provides important information regarding the effect of pearlitic microstructure refinement on crevice corrosion and introduces a facile method for in situ monitoring of crevice corrosion.

Modeling Pipeline Metal Loss Defects at Tool Speed

2018 ◽  
Author(s):  
Matthew Romney ◽  
Adrian Belanger
Keyword(s):  
Computer Simulation ◽  
Simulation Modeling ◽  
Pipeline Steel ◽  
Model Development ◽  
Metal Loss ◽  
General Corrosion ◽  
Element Analysis ◽  
Physical Test ◽  
Field Response ◽  
Flux Leakage

Accurate defect sizing is crucial for maintaining effective pipeline safety and operation. Under growing pressure from local, national and world organizations, pipeline operators demand improved magnetic flux leakage (MFL) metal-loss sizing accuracy and classification from in-line inspection (ILI) tools. The axial MFL field response in pipeline steel near a metal-loss defect is a very complex phenomenon. Although critical for proper sizing model development, the effects of tool speed due to product flow is very difficult to model during finite element analysis (FEA) and therefore is often overlooked. However, understanding the dynamic MFL response is crucial for proper ILI tool design and the development of accurate defect sizing algorithms. T.D. Williamson (TDW) utilizes dynamic computer simulation modeling, paired with laboratory testing, to develop the complex parametric relationships between metal loss geometry, pipeline material and ILI tool speed. The blend of simulation and physical test results allow for TDW to iterate more quickly across multiple physics variables with simulation models, while maintaining a firm footing in reality with physical test validation. Accurately simulating magnetic field responses of metal loss under dynamic conditions produces the data necessary to identify optimal magnetizer design, including optimizing sensor spacing and placement for metal-loss defect sizing and characterization. This paper will provide an overview of advances in the use of computer simulation modeling for predicting dynamic flux leakage field response. Besides increasing accuracy, results from this work will extend specifications beyond optimal speed ranges and provide the basis for general corrosion profilometry predictions from decomposition of the full MFL signal.

Metal Loss: Corrosion Defects Qualification and Structural Integrity Assessment

2015 ◽  
Author(s):  
Manuela Gentile ◽  
Ciro Antonio Laudonia ◽  
Lorenzo Marchionni ◽  
Antonio Parrella ◽  
Roberta Vichi ◽  
...  
Keyword(s):  
Structural Integrity ◽  
Operating Conditions ◽  
Design Stage ◽  
Metal Loss ◽  
Fluid Composition ◽  
Fe Model ◽  
General Corrosion ◽  
Line Pipe ◽  
Integrity Assessment ◽  
Strength Capacity

The management of the flow availability in presence of corrosive fluids may considerably impact on CAPEX and OPEX of offshore pipelines. A correct approach starts from the preliminary phases of a project, with the selection of the most appropriate material in relation to the nature of the corrosive fluids and expected degradation mechanisms (i.e. general corrosion, localized or mesa corrosion and pitting). The construction phases include measures that allow meeting welding requirements and safe guarding the integrity of the line-pipe. The operation shall account for the control of process parameters and transported fluid composition. In the upcoming future offshore pipeline and field development projects, challenging operating conditions in deep/ultra-deep waters means that increasingly careful considerations on the effect of metal loss: corrosion leading to local loss of material may cause a potential pipeline failure under the additional effect of functional and environmental loads, in particular the high external pressure and applied bending moment. The assessment of the structural integrity depends on the type and accuracy of available measurements. In presence of corrosion patterns and accordingly to existing standards (DNV RP-F101, ASME B31G, API 579, BS 7910) the assessment might be unduly conservative; further the presence of important combined loads is not fully covered by standard assessment format. The use of FEM numerical lab can help the evaluation of the residual strength and deformation capacity of the pipeline affected by corrosion, leading to a quite-deterministic characterization of pipeline strength capacity at design stage and in operation. Several studies (both theoretical and experimental) available in the open literature faced this issue and their findings support the proposed analysis methodology. Recently full scale tests have been conducted by the relevant Oil & Gas industry companies (such as Statoil and ENI) and the obtained results have been used for the FE Model calibration and validation of corroded pipelines. Herein an application is presented in order to understand and appreciate the proposed methodology performance in corroded pipeline assessment.

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