bluuebunny/crossref_metadata_2025_split huggingface dataset:
Validation of EMAT Technology for Gas Pipeline Crack Inspection
Authors: Kania Richard , Klein Stefan , Marr Jim , Rosca Gabriela , Riverol Elvis SanJuan , Ruda Rahim , Jansing Nikola , Beuker Thomas , Ronsky N. Daryl , Weber Ralf 
Published: July 2013

The use of the Electro-Magnetic Acoustical Transducer (EMAT) technology for crack detection by In-Line Inspection (ILI) tools has increased over the last few years. Rigorous validation of the technology leading from the initial application of EMAT inline inspection tools through to determining Probability of Detection (POD) and Identification (POI) has contributed to improved confidence and reliability. EMAT results are being utilized to determine SCC valve section severity, to review and modify hydrostatic test schedules and intervals and could potentially be implemented as a viable alternative to hydrostatic testing.
This paper describes the development of an EMAT ILI based program and the related validation process applied by the vendor, pipeline operator and in-ditch personnel. This process is illustrated by demonstrating the performance of the EMAT tool in two 20″ diameter natural gas pipelines which have a documented history of SCC. The tool identified hundreds of features in the two pipelines which were validated both in the ditch and via detailed anomaly sizing.
An Update to the UKOPA Pipeline Damage Distributions
Authors: Goodfellow Graham , Turner Susannah , Haswell Jane , Espiner Richard 
Published: July 2013

The United Kingdom Onshore Pipeline Operators Association (UKOPA) was formed by UK pipeline operators to provide a common forum for representing operators interests in the safe management of pipelines. This includes providing historical failure statistics for use in pipeline quantitative risk assessment and UKOPA maintain a database to record this data.
The UKOPA database holds data on product loss failures of UK major accident hazard pipelines from 1962 onwards and currently has a total length of 22,370 km of pipelines reporting. Overall exposure from 1952 to 2010 is of over 785,000 km years of operating experience with a total of 184 product loss incidents during this period. The low number of failures means that the historical failure rate for pipelines of some specific diameters, wall thicknesses and material grades is zero or statistically insignificant. It is unreasonable to assume that the failure rate for these pipelines is actually zero.
However, unlike the European Gas Incident data Group (EGIG) database, which also includes the UK gas transmission pipeline data, the UKOPA database contains extensive data on measured part wall damage that did not cause product loss. The data on damage to pipelines caused by external interference can be assessed to derive statistical distribution parameters describing the expected gouge length, gouge depth and dent depth resulting from an incident. Overall 3rd party interference incident rates for different class locations can also be determined. These distributions and incident rates can be used in structural reliability based techniques to predict the failure frequency due to 3rd party damage for a given set of pipeline parameters.
The UKOPA recommended methodology for the assessment of pipeline failure frequency due to 3rd party damage is implemented in the FFREQ software. The distributions of 3rd party damage currently used in FFREQ date from the mid-1990s. This paper describes the work involved in updating the analysis of the damage database and presents the updated distribution parameters. A comparison of predictions using the old and new distributions is also presented.
Enbridge Cost and Schedule Contingency Assessments
Authors: Schoenhardt Matthew , Pardais Vachel , Fortin Cheryl , Kitson Brent , Hanzel Jay 
Published: July 2013

All capital projects have an element of risk and uncertainty. In today’s business environment this requires more than just simply adding 10 percent contingency to the cost estimate to cover off project unknowns. Before sanctioning a project for hundreds of millions of dollars, Board of Directors need to know what possible cost and schedule outcomes exist in order to safe-guard shareholders’ investments. Contingency assessments must be:
• Risk-based
• Project Specific
• Repeatable
• Defendable
• Cost effective
Six years ago, Enbridge grappled with these issues and realized it needed to adopt a new method of assessing both cost and schedule contingencies. After evaluating options, Enbridge set upon developing an in-house parametric modeling solution for its contingency assessment needs.
This paper will:
• Identify various options for assessing contingency
• Review the Enbridge process
• Demonstrate the value of a simplified risk register
• Identify required data inputs
• Illustrate calibration and accuracy of assessments
• Discuss business advantages of parametric modelling
Continued Microstructure and Mechanical Property Performance Evaluation of Commercial Grade API Pipeline Steels in High Pressure Gaseous Hydrogen
Authors: Stalheim Douglas , Boggess Todd , Bromley Darren , Jansto Steve , Ningileri Shridas 
Published: July 2013

In spite of current world economic climates, recognition that alternative energy sources to the traditional fossil fuels has to be explored and understood. One potential energy source being researched and developed is hydrogen gas. Currently the most economical method of transporting large quantities of hydrogen gas is through steel pipelines. It is well known that hydrogen embrittlement has the potential to degrade steel’s mechanical properties when hydrogen migrates into the steel matrix. Consequently, the current pipeline infrastructure used in hydrogen transport is typically operated in a conservative fashion. This operational practice is not conducive to economical movement of significant volumes of hydrogen gas as an alternative to fossil fuels.
The degradation of the mechanical properties of steels in hydrogen service is known to depend on the microstructure of the steel. Understanding the levels of mechanical property degradation of a given microstructure when exposed to hydrogen gas under pressure can be used to evaluate the suitability of the existing pipeline infrastructure for hydrogen service and guide alloy and microstructure design for new hydrogen pipeline infrastructure. To this end, the microstructures of relevant steels and their mechanical properties in relevant gaseous hydrogen environments must be fully characterized to establish suitability for transporting hydrogen.
Previously data from a US Department of Energy/private sector funded project to evaluate four commercially available pipeline steels alloy/microstructure performance in the presences of gaseous hydrogen was presented in 2010. Interest in this previous work from industry and the ASME B31.12 Hydrogen Piping and Pipeline Systems codes and standards committee resulted in additional funding for continued evaluation of additional pipeline steel alloys/microstructures in the presences of gaseous hydrogen. Samples from API grades X52 (1960’s and current vintage designs), X70 (1980’s and current vintage) and X80 along with various samples from an X52 induction bend pipe and one pressure vessel steel A516 Gr 70 are being evaluated. Microstructural characterization, fracture toughness and fatigue testing in the presence of gaseous hydrogen at 800 psig and 3,000 psig are being conducted.
This paper will describe the fracture toughness results achieved to date on various commercially available pipeline steels used in the existing North American pipeline infrastructure in the presence of gaseous hydrogen at pressures relevant for transport in pipelines. Microstructures and fracture toughness performances will be compared between these in this study along with those published previously. In addition, recommendations for future work related to gaining a better understanding of steel pipeline performance in hydrogen service will be discussed.
Simulation of Liquid-Gas Replacement in Commissioning Process for Large-Slope Crude Oil Pipeline
Authors: Chen Yuanyuan , Gong Jing , Li Xiaoping , Zhang Nan , He Shaojun , Liu Jianfeng , Liu Yuwei , Wu Jiawen 
Published: July 2013

Pipeline commissioning, which is a key link from engineering construction to production operation, is aim to fill an empty pipe by injecting water or oil to push air out of it. For a large-slope crude oil pipeline with great elevation differences, air is fairly easy to entrap at downward inclined parts. The entrapped air, which is also called air pocket, will cause considerable damage on pumps and pipes. The presence of it may also bring difficulties in tracking the location of the liquid head or the interface between oil and water. It is the accumulated air that needed to be exhausted in time during commissioning.
This paper focuses on the simulation of liquid-gas replacement in commissioning process that only liquid flow rate exists while gas stays stagnant in the pipe and is demanded to be replaced by liquid. Few previous researches have been found yet in this area. Consequently, the flow in a V-section pipeline consisted of a downhill segment and a subsequent uphill one is used here for studying both the formation and exhaustion behaviors of the intake air. The existing two-fluid model and simplified non-pressure wave model for gas-liquid stratified flow are applied to performance the gas formation and accumulation. The exhausting process is deemed to be a period in which the elongated bubble (Taylor bubble) is fragmented into dispersed small bubbles. A mathematical model to account for gas entrainment into liquid slug is proposed, implemented and incorporated in a computational procedure. By taking into account the comprehensive effects of liquid flow rate, fluid properties, surface tension, and inclination angle, the characteristics of the air section such as the length, pressure and mass can be calculated accurately. The model was found to show satisfactory predictions when tested in a pipeline. The simulation studies can provide theoretical support and guidance for field engineering application, which are meanwhile capable of helping detect changes in parameters of gas section. Thus corresponding control measures can be adopted timely and appropriately in commissioning process.
Probabilistic Fitness-for-Service Assessment of Pipeline
Authors: Semiga Vlad , Dinovitzer Aaron 
Published: July 2013

Fitness for service assessments of oil and gas pipelines, conducted either at the design stage or to evaluate an indentified anomaly, are generally carried out in a deterministic manner based on conservative estimates of the required input parameters.
The following paper presents a probabilistic Fitness-for-Service (FFS) assessment approach which can be used in a risk based pipeline integrity management program. The probabilistic assessment utilizes an Advanced Monte Carlo simulation based approach and the fracture mechanics techniques described in BS 7910. The paper presents an overview of the basic approach and provides a demonstration of its capabilities in terms of estimating the risk of failure (or probability of failure) associated with a pipeline over time, due to the presence of a crack like flaw. The paper also discusses the sources of data and inherent assumptions used to model various input parameters required for a typical FFS analysis carried out according to BS 7910.
Remaining Life Assessment of ERW Flaws: A Case Study
Authors: Cazenave Pablo , Tandon Samarth , Tinacos Katina , Gao Ming , Katz David C. , Limon Sergio , Van Hook Michael 
Published: July 2013

Recent failures in seam weld pipe have raised concerns within the pipeline industry over the integrity of such welded pipe. Low-Frequency (LF) Electric Resistance Welded (ERW) pipe manufactured prior to 1970, in particular, can be susceptible to failures caused by hook cracks, lack of fusion and other planar defects should the weld area exhibit low toughness.
Integrity management regulations and Pipeline operators are evaluating potential methodologies to address and mitigate the LF-ERW seam weld threat. A program has been initiated at Williams Northwest Pipeline GP (NWPGP) to address the integrity management of its pre-70s ERW pipelines.
In this case study, as part of an overall integrity management program, a hydrostatic test and fatigue analysis based methodology for addressing the LF-ERW seam weld threat is presented. The methodology was applied to 15 pre-1970’s natural gas pipelines. The results and findings are summarized in terms of the integrity threat mitigation and maintenance strategies.
Extension of a Material Model for Pipeline Steels
Authors: Hart James D. , Zulfiqar Nasir , Zhou Joe , Adams Keith 
Published: July 2013

Pipeline steel stress-strain curves obtained from tension and compression testing of longitudinally and circumferentially oriented specimens of the pipe wall can be significantly different e.g., the pipe material is anisotropic. The anisotropic behavior can result from the manufacturing process (e.g., due to cold expansion of UOE pipe) and can also be influenced by strain aging effects (e.g., due to heated application of pipe coating materials). As described in previous work, the Mroz multilinear kinematic hardening plasticity theory has the ability to accurately model different types of anisotropic pipe material behavior including relatively “sharp” uniaxial circumferential tension response and relatively well-rounded uniaxial longitudinal tension and compression response. The stress-strain curve fitting is accomplished by essentially selecting the sizes and initial positions of elliptical von Mises yield functions in stress-space.
A previously developed and published 8-parameter model is well-suited for fitting a matched pair of longitudinal tension (LT) and hoop tension (HT) stress-strain curves as might typically be available from a strain-based pipeline design project. Fitting a pair of “target” LT-HT stress-strain curves is accomplished using a “2-root” fitting procedure where the roots correspond to locations where the yield functions intercept the stress axes in two-dimensional (longitudinal-hoop) stress space. In this paper, the previously described 8-parameter/2-root fitting procedure is extended to a 10-parameter/3-root fitting procedure for situations where a matched “triple” of pipe steel stress-strain curves are available (e.g., LT, HT and longitudinal compression or LC). This extension allows for analysis of strain-based design conditions using an analytical pipe steel, which provides an accurate representation of the uniaxial longitudinal and circumferential stress-strain response of the pipeline material. This paper reviews the 8-parameter/2-root fitting procedure and outlines the extension to the 10-parameter/3-root fitting approach including example application.
Types of Uncertainty and Their Impact on Target Risk or Reliability
Authors: Huyse Luc , Kariyawasam Shahani 
Published: July 2013

The main objective in using reliability based methodologies is to provide consistent safety by explicitly accounting for uncertainties in a probabilistically quantified manner. Reliability methods also allow the articulation of the level of safety. This level of consistency in safety cannot be achieved in a deterministic analysis using safety factors. However, reliability based methods can be used to calibrate and improve deterministic methods to improve the consistency of the safety level. Providing consistent safety enables optimization of maintenance activities which enables the safest system to be provided using the available resources. Currently used deterministic and reliability based methods are both examined and discussed. Gaps and areas of improvement are identified with the objective of improving safety and explicitly articulating and communicating the level of safety.
Effective use of quantitative risk and reliability methodologies requires quantitative data that describes the current state of the pipeline, the anticipated future state as well as the failure limit state. In maintaining oil and gas pipelines this level of quantitative data of the pipeline is available when pipelines are in-line inspected. Although reliability-based assessments are by no means restricted to corrosion management, the reliability based maintenance program at Pipeline Research Council International (PRCI) has been foremost applied to corrosion management because in-line inspection (ILI) data is adequately accurate to perform reliability based assessments. Guidelines for a reliability based maintenance program have been developed and projects executed to validate and demonstrate the implementation of these methodologies. The main learning from these guidelines and subsequent validation projects has been useful in identifying the process for improving integrity related decision making, the sensitivities of these methodologies, the impact of physical uncertainty and knowledge uncertainty, and the challenges in defining and applying target criteria. These identified areas are explored and discussed.
Risk Evaluation at Natural Gas Compressor Stations and Above Ground Installations
Authors: Cleaver R. P. , Maycock K. , Halford A. R. , Potts S. J. , McCollum D. J. , Sadd A. W. T. , Acton M. R. 
Published: July 2013

As part of a commitment to understanding and minimising the risks of its operations, National Grid has carried out a programme of theoretical and experimental work, supplemented by site surveys, to develop a methodology to assess the risks from compressor sites and other Above Ground Installations (AGIs) associated with the natural gas transmission pipelines. A computer package has been produced to encode this methodology to make it easer to use. The package contains a number of models that assess the consequences of releases at fixed installations. These are linked with frequency data to enable a risk assessment to be performed.
This paper gives an overview of the package. By means of worked examples, typical input information required by the model is explained and the output information available is presented. The paper includes a discussion on how the output from the model can be used in various practical applications; from ranking the risks at a number of sites, assessing the fire fighting provision at a site or examining the impact of changes on the layout at a site. A worked example is provided to show how the results can be used to extend the guidance for the separation distances required from processing plant to the site boundary at a wider range of sites.
Research and Development of X70 Large Diameter UOE Linepipe With High Deformability for Strain-Based Design Pipeline
Authors: Zheng Lei , Bai Mingzhuo , Zhang Bei , Cui Tiancheng , Xu Haishen 
Published: July 2013

In recent years, high strength linepipe needs high longitudinal deformability to meet the requirements of strain-based design pipeline employed when passing through geologic hazard-prone regions, such as seismic areas, landslide zones, permafrost zones, etc. The geologic hazard section of the natural gas pipeline from Myanmar to China is going to utilize a strain-based design. Linepipes with high deformability are required in these areas.
The microstructures with different phases and the effect of the microstructure on deformability of pipeline steel were studied. Based on a dual phase of ferrite and banite microstructure design, the X70 grade UOE linepipe with low yield-tensile strength ratio, good uniform elongation and high stress ratio were developed. Two dimensions of UOE linepipe for the strain-based design area of Myanmar-China pipeline project, which were 1016mm O.D. and 17.5mm W.T., 1016 mm O.D. and 21.0mm W.T., were industrially trial-produced.
The transverse properties of the trial produced linepipes meet the requirements of X70 steel grade of API Specification 5L. And also the linepipe has good toughness, the Charpy impact energy at −5°C is more than 200J, and the shear fracture area of DWTT test is more than 85% at 0°C. The longitudinal tensile properties of the trial produced linepipe exhibit good deformability. The stress-strain curve shows a typical round-house shape, the uniform elongation u-EL% is more than 7%, the yield-tensile strength ratio is lower than 0.80, the stress ratios of Rt1.5/Rt0.5, Rt2.0/Rt1.0 and Rt5.0/Rt1.0 are more than 1.100, 1.040 and 1.088 respectively. The properties of the linepipe after aging at 200°C for 5min to simulate the coating process of the pipe were also investigated. The results show that the linepipe trial-produced has good strain-aging resistance.
Development of a Reliable Model for Evaluating the Ductile Fracture Propagation Resistance for High Grade Steel Pipelines
Authors: Di Biagio M. , Demofonti G. , Mannucci G. , Iob F. , Spinelli C. M. , Schmidt T. 
Published: July 2013

The recent experience on ductile fracture propagation control on gas pipelines has shown that the applicability of the Battelle Two Curve Method (based on Charpy-V energy) to high grade steel pipes from API5L-X80 to X120 (ISO3183-L555M to L830M) operated at very high hoop stress values (≥500 MPa) is highly questionable.
The reduced geometry of the specimen, the intrinsic low value of ductility of very high strength steels, as low work-hardening and low value of the strain at maximum load are pointed out as the main causes of the mismatch.
Starting from these assumptions a new EPRG (European Pipeline Research Group) project has been launched with the aim to develop, with reference to the ductile fracture propagation resistance, a suitable fracture parameter(s) with an associated laboratory methodology based on a simple sample which would be able to take into account the role of the ductility of the material on this specific fracture event.
The present paper shows the approach adopted in this EPRG Project: an innovative approach based on “plastic damage model” which allows to describe the stable ductile crack propagation by means of stress-state parameters (named triaxiality and deviatoric parameters).
Moreover the proposed “damage model” has been implemented inside a commercial finite element code and used to predict the fracture crack propagation behaviour of Single Edge Notch Bend (SENB) tests in terms of load-displacement diagram and residual plastic deformation.
One of the main topics of this project was the application of this method to six selected grade steels (with grades in the range of API X65 – X100) many of them coming from experimental full scale burst tests. The comparisons between experimental results and numerical simulations are substantially good; besides the results confirm that Charpy-V specimens, during the fracture propagation, work in different “constraint” conditions with respect to pipe and that DWTT specimen is in the middle between the two. Finally the “damage model approach” seems also able to discriminate between low and high grade steels in terms of failure deformation at rupture. So it resulted very promising to quantify the role of both ductile of the steel and geometrical constraint of the specimen in the ductile fracture propagation event.