A Case Study on the Application of Structural Reliability Analysis to Assess Integrity for Internal Corrosion of Unpiggable Pipelines

2016 ◽  
Author(s):  
Katherine Taylor ◽  
Susannah Turner ◽  
Graham Goodfellow
Keyword(s):  
Corrosion Rate ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Probability Distributions ◽  
Sources Of Information ◽  
Feature Size ◽  
Internal Corrosion ◽  
Pipeline Failure ◽  
Alternative Sources

Operators wish to understand the condition of their pipelines to manage ongoing integrity. Information on the condition of the pipeline along its entire length can be obtained using in-line inspection (ILI). However, some pipelines cannot be internally inspected due, for example, to tee connections, tight bends, low flow or to a lack of launcher and receiver facilities. The condition of these ‘unpiggable’ lines can sometimes be largely unknown. To aid the understating of the pipeline condition without ILI data, operators will often rely on alternative sources of information, such as localised external inspections, model predictions and company and individual experience. However, there may be significant uncertainty associated with these alternative data sources when using them to assess the condition of the entire pipeline. This uncertainty may be understood by applying a probabilistic approach to the assessment of pipeline integrity using structural reliability analysis (SRA) methods. An SRA approach applies probabilistic input parameters to a failure prediction model for a defined limit state function. Previous IPC papers[1,2,3] have presented guidance on probabilistic assessments to model pipeline failure. Recommended probability distributions are presented which account for uncertainties associated with line pipe properties, defect sizing and the error associated with the predicted failure model. However, there is little published guidance readily available on recommended defect characteristic distributions specific to internal corrosion features. Parameter distributions are recommended for defect sizing based on empirical data, which are mainly used for external corrosion features. In this paper, a case study is used to present a practical application of an SRA methodology for assessment of pipeline integrity with respect to internal corrosion. Discussion is presented on alternative sources of information for the assessment when ILI data is unavailable, including targeted external inspections of unpiggable lines and data sets from comparable piggable lines. Probability distributions are derived from the available inspection data for the internal corrosion feature size and corrosion rate input parameters to the SRA. Probabilistic analysis is used to account for the expected population of unknown features in the uninspected parts of the pipelines. The expected feature size, corrosion rate and feature density calculated are used in the SRA to estimate the total probability of failure due to internal corrosion over time for the entire length of the pipeline. Recommendations are provided on the application of an SRA methodology to assess pipeline failure due to internal corrosion.

scholarly journals Framework for evaluating risk of limited sight distance for permitted left-turn movements: case study

2016 ◽  
Vol 43 (4) ◽  
pp. 369-377 ◽  
Author(s):  
Ahmed Osama ◽  
Tarek Sayed ◽  
Said Easa
Keyword(s):  
Reliability Analysis ◽  
Probability Distributions ◽  
Video Data ◽  
Analysis Framework ◽  
Left Turn ◽  
Sight Distance ◽  
Time Gap ◽  
Input Variables ◽  
The City

A reliability analysis framework is used to evaluate the risk of limited sight distance for permitted left-turn movements due to the presence of opposing left-turn vehicles. Two signalized intersection approaches in the city of Surrey were used as case studies for the framework. Geometric and traffic video data was collected and analyzed using a computer vision tool to extract the input variables probability distributions. The data was used in the reliability analysis where first-order and Importance Sampling methods were performed. The analysis showed that the probability of non-compliance was considerable at one approach due to its large left-turn lane offset. The analysis also showed that the probability of non-compliance increased substantially when the obstacle vehicle was a bus rather than a passenger car. Moreover, the time gap had a higher impact on the probability of non-compliance compared to speed. Strategies were suggested to overcome the high probability of non-compliance.

scholarly journals Life Prediction of Crude Oil Pipeline to Mitigate Leakages: A Case Study of an NPDC Major Pipeline in OML30, Nigeria

2021 ◽  
Author(s):  
Henry Freedom Ifowodo ◽  
Chinedum Ogonna Mgbemena ◽  
Christopher Okechukwu Izelu
Keyword(s):  
Crude Oil ◽  
Oil And Gas ◽  
Gas Field ◽  
Internal Corrosion ◽  
Oil Pipeline ◽  
Oil And Gas Field ◽  
Pipeline Failure ◽  
Pipeline Failures ◽  
Major Pipeline

Abstract Pipeline leak or failure is a dreaded event in the oil and gas industries. Top events such as catastrophes and multiple fatalities have occurred in the past due to pipeline leak or failure especially when loss of contents was met with fire incidents. It is therefore imperative that the causes of pipeline failure are tackled to prevent or mitigate leak incidents. This is expedient to curb the menace that goes with leak incidents, such as destruction of the environment and ecosystem; loss of assets, finance, lives and property; dangers to workers and personnel, production downtime, litigation and dent to company’s reputation. This work focuses on the investigation of the actual cause of sudden pipeline failures and frequent pipeline leaks that often result to sectional pipeline replacement before the expiration of their anticipated life cycle in OML30 oil and gas field. The pipeline material selected, the standard of the minimum wall thickness of the material, the corrosive nature of the pipeline content and the observed internal corrosion rate were probed. An analysis of the rate of thinning and diminution of the internal wall of the pipeline by monitoring the interior rate of corrosion was used to forecast the remaining life of a crude oil pipeline and predict the life expectancy of a newly replaced or installed pipeline or installed pipeline.

Comparisons of Two Non-probabilistic Structural Reliability Analysis Methods for Aero-engine Turbine Disk

2017 ◽  
Vol 34 (3) ◽  
Author(s):  
Zheng Liu ◽  
Le Yu ◽  
Yan-Feng Li ◽  
Jinhua Mi ◽  
Hong-Zhong Huang
Keyword(s):  
Probability Theory ◽  
Reliability Analysis ◽  
Structural Reliability ◽  
Turbine Disk ◽  
Imprecise Probability ◽  
Structural Reliability Analysis ◽  
Theoretical System ◽  
Analysis Methods ◽  
Aero Engine

AbstractTurbine disk is a key component of aero-engine and the failure of turbine disk will lead to disastrous consequences, making the structural reliability analysis for the turbine disk as an urgent issue. Taking the turbine disk as the case study, this paper will compare two non-probabilistic structural reliability analysis methods of imprecise structural reliability analysis and interval structural reliability analysis aiming at providing a more profound understanding about the theoretical system of imprecise probability theory. Moreover, according to the comparisons, this paper will predict the prospects or the works should to be done for the widely application of imprecise probability theory.

A Robust Approach to Pipeline Integrity Management Using Direct Assessment Based on Structural Reliability Analysis

2004 ◽  
Author(s):  
Marcus McCallum ◽  
Andrew Francis ◽  
Tim Illson ◽  
Mark McQueen ◽  
Mike Scott ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Voltage Gradient ◽  
Pipeline System ◽  
Pipe Failure ◽  
Internal Corrosion ◽  
Direct Assessment ◽  
Structural Reliability Analysis ◽  
Integrity Management ◽  
External Corrosion

Approximately 1450 km (900 miles) of a 4020-km (2500 mile) natural gas pipeline system operated by Crosstex Energy Service L.P in Texas are subject to the Texas Railroad Commission’s (TRRC) integrity management rules. Consequently, in preparation for the construction of an extensive and robust integrity management program, Crosstex commissioned Advantica to assist in the development and application of a pilot study on a 13.4 km (8.3 mile) section of a 14” pipeline. The purpose of the study, which is based on Structural Reliability Analysis (SRA), was to compare the level of integrity that could be inferred from the use of Direct Assessment (DA) techniques with the level that could be inferred from ILI results. Based on a preliminary assessment of available data, the study identified both external and internal corrosion as potential threats to integrity. SRA was used in conjunction with ‘Bayesian Updating’ to determine the probability of pipe failure due to external corrosion, taking account of results from above-ground measurements and a number of bell-hole excavations. The above-ground survey techniques utilized included Close Interval Survey (CIS) and Direct Current Voltage Gradient (DCVG). A similar approach was adopted to address the threat due to internal corrosion, but hydraulic modelling was substituted for the above-ground measurements. A third study based on SRA was used to determine the combined probability of failure due to both internal and external corrosion taking account of ILI results. The outcome of the analyses demonstrated that the level of integrity that could be inferred from the use of Crosstex’ DA methodology was similar to that which could be inferred from the use of ILI. The results were presented to the TRRC for review and approval. This paper gives a detailed description of the SRA based methodology that was employed by Crosstex and presents the results that clearly demonstrate the comparability of ILI and DA for the purpose of integrity management.

Reliability analysis for complex systems subject to competing failure processes in an uncertain environment

2020 ◽  
Vol 39 (3) ◽  
pp. 4331-4339
Author(s):  
Baoliang Liu ◽  
Zhiqiang Zhang ◽  
Yanqing Wen ◽  
Shugui Kang ◽  
Yanxin Guo ◽  
...  
Keyword(s):  
Complex Systems ◽  
Reliability Analysis ◽  
Uncertainty Theory ◽  
Probability Distributions ◽  
External Shocks ◽  
Process Reliability ◽  
Degradation Models ◽  
Renewal Reward Process ◽  
Internal Degradation

Reliability analysis of complex systems subject to competing failure processes based on probability theory has received increasing attention. However, in many situations, the observed data is too limited to estimate the parameters and probability distributions of the system by statistic methods. To address this problem, an uncertain degradation models is proposed in this paper under the framework of uncertainty theory. Based on this model, a complex system which is subject to both continuous internal degradation and external shocks is introduced. The continuous internal degradation of the system is controlled by some uncertain factors, and the external shocks are deemed to an uncertain renewal reward process. Reliability for the complex systems is obtained by employing the uncertainty theory. Finally, a case study is presented to demonstrate the effectiveness of the results obtained in the paper.

scholarly journals The Mainstream Media and United States' Policy in El Salvador

2016 ◽  
Vol 4 (2) ◽  
pp. 453-461
Author(s):  
Wassim Daghrir
Keyword(s):  
United States ◽  
El Salvador ◽  
Political System ◽  
Typical Case ◽  
Sources Of Information ◽  
Mainstream Media ◽  
The Press ◽  
The Us ◽  
Alternative Sources

As far as the press of such a democratic political system is concerned, one would expect the American mainstream media to act independently of the government's will by putting the official pretexts and objectives for interference abroad under serious questioning -before accepting or rebutting them- looking for alternative sources of information, and instituting the conditions for a fair debate -by offering the opportunity to several conflicting opinions to argue and debate and then come out with the most convincing conclusions. In order to check if the US mainstream media acted as an independent organ during U.S. interference in El Salvador, I will examine their treatment of the official objectives for intervention as well as the most prominent themes and methods they applied during their coverage of a typical case study of American Global Realism.

Insights in the Application of Structural Reliability Analysis (SRA) for Challenging Pipeline Lateral Buckling Design

2014 ◽  
Author(s):  
Elena Gerginov ◽  
Andrew Rathbone ◽  
Chris Sullivan ◽  
Terry Griffiths
Keyword(s):  
Reliability Analysis ◽  
Structural Reliability ◽  
Complex Analysis ◽  
Real Life ◽  
Pipeline System ◽  
Lateral Buckling ◽  
Considerable Uncertainty ◽  
Structural Reliability Analysis ◽  
Levels Of Detail ◽  
Pipeline Failure

Lateral buckling of pipelines is influenced by, and sensitive to, a complex combination of factors associated with considerable uncertainty. Key elements such as pipe to soil friction, vertical and horizontal imperfections can vary significantly not only along sections of the same pipeline, but at the same location over time. These factors carry a probabilistic likelihood of occurrence that results in a probabilistic distribution of buckle formation forces and locations, as well as post buckle loads, as described by Rathbone et. al. (2008). To effectively capture all possible combinations of inputs and results, and thus gain a full understanding of potential buckle behaviour and interaction, would require many individual finite element analyses to be undertaken, which is not viable. The paper describes new insights into challenging pipeline lateral buckling design gained through use of a highly adaptable Structural Reliability Analysis (SRA) method. It discusses the difficulties in defining pipeline and seabed complexities while still retaining adequate detail to fully describe the pipeline system. A range of realistic lateral buckling design scenarios will be discussed, illustrating how to reduce existing limitations in probabilistic design through the use of the SRA method. The method is flexible enough to enable varying levels of detail to be modelled, from simple idealised checks of buckling susceptibility, which are commonly performed during the early phases of design, to the more complex analysis of pipeline failure, performed during detailed design. The paper will demonstrate the ability for the method to capture complex real life scenarios such as the effect of a bi-modal distribution in observed pipeline embedment, as well as the influence of covariance between frictions, on the probability of buckling and resulting strains.

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