bluuebunny/crossref_metadata_2025 huggingface dataset:
Practical Methodology of Predictive Maintenance for Pipelines
Authors: Timashev S. A. , Bushinskaya A. V.
Published: April 2011

Predictive maintenance (PdM) is the leading edge type of maintenance. Its principles are currently broadly used to maintain industrial assets [16]. Yet PdM is as yet not embraced by the pipeline industry. The paper describes a comprehensive practical risk based methodology of predictive maintenance of pipelines for different criteria of failure. For pipeline systems the main criterion is integrity. One of the main causes of loss of containment is pipe wall defects which grow in time. Any type of analysis of pipeline state (residual life time, probability of failure (POF), etc.,) is based on the sizes of discovered defects, which are assessed during the ILI or DA. In the developed methodology pipeline strength is assessed using one of the five internationally recognized design codes (the B31G, B31mod, DNV, Battelle, Shell 92). The pipeline POF is calculated by the comprehensive Gram-Charlier-Edgeworth method [14]. Having in mind that the repair actions are executed on particular cross-sections of the pipeline, the POF are calculated for each defect present in the pipeline. When calculating POFs, the defect sizes (depth, length and width), wall thickness and pipe diameter, SMYS of the pipe material, the radial and longitudinal corrosion rates, and operating pressure (OP) are considered random variables each distributed according to its PDF. In the proposed method of PdM of pipelines the remaining life time can be assessed using following criteria: POF = Qth; dd = 80%wt; SMOP = MAOP; ERF = MAOP/SMOP, if ERF ≥ 1, the pipeline needs immediate repair; dd = 100%wt. Here Qth is the ultimate permissible POF, dd is the depth of the most dangerous defect, wt is pipe wall thickness, SMOP is the maximal safe operating pressure SMOP = DF·Pf, MAOP is the Maximum Allowable Operating Pressure, Pf is the failure pressure, DF is the design factor (for B31Gmod DF = 1.39), ERF is the Estimated Repair Factor. The above criteria are arranged in descending order according to the growing level of their severity in time. The prediction of future sizes of growing defects and the pipeline remaining life time are obtained by using consistent assessments of their corrosion rates CRs. In the PdM methodology these CRs may be considered as deterministic, semi-probabilistic or fully stochastic values. Formulas are given for assessing the CRs using results of one ILI, two consecutive ILI, with or without verification measurements, and for the case when several independent types of measurements are used to assess the defect sizes. The paper describes results of implementation of the developed methodology on a real life pipeline. The time to reach each of the limit states given above was calculated, using results of two consecutive ILI divided by a three year interval. Knowledge of these arrival times permits minimizing the maintenance expenditures without creating any threats to its integrity and safety.
Bayesian Update of the Number of Defects Present in the Pipeline
Authors: Kuznetsov V. V. , Malyukova M. G. , Timashev S. A.
Published: April 2011

Analysis of reliability methods which are currently used in design and operation of pipelines as systems shows that the classical approach, imported from the structural reliability theory—considering the pipeline as a system of sequentially connected elements—does not work. The main reason for this is that not all defects present in the pipeline actually provide an input into the total probability of failure (POF) of the pipeline system, given the depth of failure prediction, and the actual deterioration model. The second reason is that the results of any in-line or DA inspection don’t give the actual number of true defects. The set of defects detected by the ILI tool always contains some sub-set of false (phantom) defects, and doesn’t contain a sub-set of missed out defects. Both these sub-sets may seriously influence the quantitative assessment of the POF. This paper is dedicated to creating a practical method of updating the true number of defects in a pipeline after conducting an ILI and consequent verification of ILI results. A straightforward method of doing this was initially proposed by one of the authors in an IPC paper [7]. A more accurate comprehensive method based on the Bayesian procedure is presented is this paper. It is assumed that the prior experimental data and the probability distribution function (PDF) for this data are known. The goal is to find the best fit parameter of this PDF, having results of the verification measurements. Algorithm for solving this problem is presented in the paper. This approach was used detected during an ILI, followed by verification measurements [7]. Having the numbers of discovered and true defects, a prediction is made of the most probable number of true defects in each of the intervals of defects’ parameter of interest. This result can be used when assessing the quality of the ILI tool, the results of a specific pig run, used as an input when solving corresponding problems of pipeline POF, and for planning the risk based inspections.
Evaluation Model for Enterprise Standardization Programs: The Case of Petrobras Transporte’s Marine Terminals Unit
Authors: Maldonado Luciano , de Almeida Maria Fatima Ludovico , Penchina´ Pereira Paulo , Santos Ubirajara , Ferreira Manoel Henrique , Mu¨ller Gabriela
Published: April 2011

This paper describes an innovative evaluation model applied to Petrobras Transporte’s “Marine Terminals Standardization Program” based on updating approaches of programs evaluation and organizational learning. Since the program was launched in 2004, the need for having an evaluation model able to evaluate its implementation progress, to measure the degree of standards compliance and its potential economic, social and environmental impacts has become evident. Within a vision of safe and environmentally responsible operations of marine terminals, this evaluation model was jointly designed by Petrobras Transporte and PUC-Rio to promote continuous improvement and learning in operational practices and in the standardization process itself. Petrobras Transporte believes that standardization supports its services and management innovation capability by creating objective and internationally recognized parameters, targets and metrology for its business activities. The conceptual model and application guidelines for this important tool are presented in this paper, as well as the next steps towards its implementation.
Visual Operations Management Tools in Oil Pipelines and Terminals Standardization Processes
Authors: de Almeida Maria Fatima Ludovico , Santiago Adilson , Ribeiro Kassandra Senra , Arruda Daniela Mendonc¸a
Published: April 2011

This paper describes the process by which visual operations management (VOM) tools were implemented, concerning standards and operational procedures in Petrobras Transporte’s Oil Pipelines and Terminals Unit. It provides: (i) a brief literature review of visual operations management tools applied to total quality management and the standardization processes; (ii) a discussion of the assumptions from the second level of VOM (visual standards) upon which Petrobras Transporte’s oil pipelines and terminals business processes and operational procedures are based; and (iii) a description of the VOM implementation process involving more than 100 employees and one illustrative example of “Quick Guides” for right-of-way management activities. Finally, it discusses the potential impacts and benefits of using VOM tools in the current practices in Petrobras Transporte’s Oil Pipelines and Terminals Unit, reinforcing the importance of such visual guides as vital to implement regional and corporate procedures, focusing on the main operational processes.
Plastic Collapse of API 5L X65 Pipe Having Dent Defects Under Internal Pressure and Bending Load
Authors: Baek Jong-hyun , Kim Young-pyo , Kim Cheol-man , Kim Woo-sik , Koo Jae-mean , Seok Chang-sung
Published: April 2011

The objective of this study was to investigate the effect of the dent magnitude on the collapse behavior of dented pipe subjected to a combined internal pressure and in-plane bending. The plastic collapse behavior and bending moment of the dented pipe with several of dent dimensions were evaluated by using elastic–plastic finite element (FE) analyses. The indenters used to manufacture the dents on the API 5L X65 pipe were hemispherical rod type with diameter of 40, 80, 160 and 320 mm. Dent depths of 19, 38, 76, 114 and 152 mm were introduced on the pipe having a diameter of 762 mm and a wall thickness of 17.5 mm in analyses. A closing or opening inplane bending moment was applied on the dented pipes pressurized under internal pressure of the atmospheric pressure, 4, 8 and 16 MPa. The FE analyses results showed that the plastic collapse behavior of dented pipes was considerably governed by the bending mode and the dent geometry. Moment-bending angle curves for dented pipe were obtained from computer simulation and evaluated with a variety of factors in FE analyses. Load carrying capacity of dented pipes under combined load was evaluated by TES (Twice Elastic Slope) moments. Load carrying capacity of pipe having up to 5% dent depth of outer diameter was not reduced compared with that of plain pipe. Opening bending mode had a higher load carrying capacity than closing bending mode under combined load regardless of dent depth. TES moment was decreased with increasing the dent depth and internal pressure regardless of bending modes.
A Model to Estimate the Failure Rates of Offshore Pipelines
Authors: De Stefani Vania , Carr Peter
Published: April 2011

Pipelines are subjected to several threats which can cause failure of the line, such as external impact, mechanical defects, corrosion and natural hazards. In particular, offshore operations present a unique set of environmental conditions and adverse exposure not observed in a land environment. For example, offshore pipelines located near harbor areas and in major shipping lanes are likely to be exposed to the risk of damage from anchor and dropped object impact. Such damage may result in potential risk to people and the environment, and significant repair costs. Quantitative Risk Assessment (QRA) is a method which is often used in the oil and gas industry to predict the level of risk. In QRA calculations the frequency of an incident is often assessed by a generic failure frequency approach. Generic failure frequencies derived from local incident databases are largely used in pipeline risk assessments. As a result, risk assessments for offshore pipelines may not reflect accurately operational experience for a specific pipeline or region of operation. In addition, a better understanding of the causes and characteristics of pipeline failure should provide important information to improve inspection and maintenance activity for existing pipelines and to aid in selection of design criteria for new pipelines. This paper presents an analysis of the failure data from various pipelines databases to see if there is a common trend regarding failure rates, and failure-rate dependence on pipeline parameters. A breakdown of the causes of failure has been carried out. The effect on failure frequency of factors such as pipeline age, location, diameter, wall thickness, steel grade, burial depth, and fluid transported have been investigated and are discussed. The objective of this paper is to provide a guideline for the determination of failure frequency for offshore pipelines and to describe a new model developed for use within BP for this purpose. This model uses historical databases and predictive methods to develop failure frequencies as a function of a range of influencing parameters.
Influence of the Forming Operations on the Yield Stress Measured on Pipe
Authors: Thibaux Philippe , Van den Abeele Filip
Published: April 2011

The yield stress of pipes is measured among purposes to assess the resistance of the pipe to the internal pressure of the fluid. Unfortunately, it is not possible to sample a straight specimen in the hoop direction, and therefore the pipe has to be flattened prior to testing. In the present investigation, different materials were tested in tensile–compression mode in order to provide data for a kinematic hardening model. Based on this experimental data set, a model was built to take into account several features of the material behaviour (presence of yield point elongation, strain hardening, etc…) and the processing route (longitudinal or spiral seam weld, expander, hydrotest…). Pipe production was also sampled at different moments (base material, after leveling, after pipe forming, after hydrotest). The testing program included tensile testing and ring expansion tests. The results show that the model gives a prediction in good correspondence with the experimental results. The model also reproduces several experimental facts, like for example the presence of a yield point elongation on the base material and its absence on the flattened pipe sample. Finally, the model is compared with an industrial database containing different steel grades (from grade B to X80) and different ratios of wall thickness over diameter (t/OD) ratios. The difference of yield stress between coil and pipe is predicted on this database with an accuracy of 20MPa.
HFI-Welded Pipes: Where Are the Limits?
Authors: Brauer Holger , Lo¨bbe Hendrik , Bick Michael
Published: April 2011

The high frequency induction (HFI) method for production of longitudinally welded pipes was introduced in the early sixties. Initially HFI-welded pipes served more or less only as a low-cost product for standard applications without increased requirements. The growing demand for energy in North America, Europe and the Far East over the last decades has resulted in an increase in the exploration and exploitation of natural gas and oil resources in remote environments under aggravated conditions. This led to more demanding requirements on the mechanical-technological properties of the pipes. Additionally, an accelerated increase of safety awareness can be observed for operation of pipelines, in order to prevent environmental or population damage. Salzgitter Mannesmann Line Pipe GmbH (MLP) coped with the growing responsibilities by having optimized the HFI-welding process over the last decades, in order to produce top quality pipes suitable for practically all requirements. The modifications to this manufacturing process have resulted in a smaller scatter in geometrical pipe parameters and in optimisation of the relevant mechanical-technological properties. This led to HFI-welded pipes which, besides the aspect of lower cost, now offer several further advantages, compared to seamless pipes or SAW-pipes, and enables the use for economical and safe applications. The present paper deals with the compliance of the progressive application requirements, using HFI-welded pipes from Salzgitter Mannesmann Line Pipe works. It will be focussed on the increased production capabilities and mechanical-technological properties of diameters up to 24″ (610.0 mm) and 1″ (25.4 mm) wall thickness, as well as higher API 5L and 5CT grades up to X70M for sour-service and weldable P110, respectively. As there is also an increasing tendency to use steel pipes for structural applications which require an enhanced spectrum of dimensions in recent years, the paper will provide details of the upgraded product portfolio for structural hollow sections (circular, square and rectangular) at MLP.
Full-Scale Burst Test of Hydrogen Gas X65 Pipeline
Authors: Aihara Shuji , Lange Hans I. , Misawa Kei , Imai Yasuhito , Sedei Yu , O̸stby Erling , Thaulow Christian
Published: April 2011

Full-scale burst test of X65 UOE linepipe, with 559mm outer diameter and 13.5mm wall thickness, pressurized at 16MPa by hydrogen gas was conducted. A 735mm long crack was introduced by explosive shaped charge over circumferential weld. The cracks were initiated and propagated in the both directions. The propagated crack lengths were 600mm and 270mm. J integral resistance curves were obtained from drop-weight as well as quasi static tests for the tested pipe material which was subjected to hydrogen charging. The tested steel showed little change in the resistance curves under realistic charging condition. Numerical simulation model of dynamic crack propagation, coupled with gas decompression behavior considering gas escape from opened crack, showed that an initiated crack was arrested at shorter distance in hydrogen gas pipelines than in methane gas pipelines, primarily due to earlier gas decompression in the former. The present results, together with the earlier full-scale burst tests conducted by the authors, demonstrated that hydrogen gas pipelines can be operated safely by using modern high-strength and high-toughness steel linepipes.
Deterministic QRA Model and Implementation Experience via an Integrity Management Software Tool
Authors: Dawson Jane , Colquhoun Iain , Yablonskikh Inessa , Wenz Russell , Nguyen Tuan
Published: April 2011

Current risk assessment practice in pipeline integrity management tends to use semi-quantitative index-based or model-based methodologies. This approach has been found to be very flexible and provide useful results for identifying high-risk areas and for prioritizing physical integrity assessments. However, as pipeline operators progressively adopt an operating strategy of continual risk reduction with a view to minimizing total expenditures within safety, environmental, and reliability constraints, the need for quantitative assessments of risk levels is becoming evident. Whereas reliability-based quantitative risk assessments can be and are routinely carried out on a site-specific basis, they require significant amounts of quantitative data for the results to be meaningful. This need for detailed and reliable data tends to make these methods unwieldy for system-wide risk assessment applications. This paper describes methods for estimating risk quantitatively through the calibration of semi-quantitative estimates to failure rates for peer pipeline systems. By applying point value probabilities to the failure rates, deterministic quantitative risk assessment (QRA) provide greater rigor and objectivity than can usually be achieved through the implementation of semi-quantitative risk assessment results. The method permits a fully quantitative approach to suit the operator’s data availability and quality, and analysis needs. The paper also discusses experiences of implementing this type of risk model in Pipeline Integrity Management System (PIMS) software and the use of and integration of data via existing pipeline geographical information systems (GIS).
Study of the Susceptibility of API 5L X80 Girth Welds to Sulfide Stress Corrosion Cracking and Hydrogen Embrittlement
Authors: Forero Ballesteros Adriana , da Cunha Ponciano Jose´ A. , Bott Ivani de S.
Published: April 2011

The growing demand for natural gas and oil, as energy sources, has driven industry’s need for ever-increasing strength levels in oil and gas transmission pipeline materials in order to achieve safe and economic transportation. The current world trend points to the use of pipes with larger diameters and thinner wall thicknesses, operating under high pressure. In addition, pipeline steels for sour service must exhibit good Hydrogen Induced Cracking (HIC) and Sulphide Stress Corrosion Cracking (SSCC) resistance. This study evaluates the susceptibility of API 5L-X80 girth welds to SSCC and Hydrogen Embrittlement (HE). Slow strain rate tensile (SSRT) tests and Hydrogen Permeation tests were performed at room temperature, in different acidic environment containing sodium thiosulfate solutions. Most of the SSRT tests undertaken in solution, showed a loss of ductility and a decrease in the reduction of area, as compared with tests conducted in air. The susceptibility to HE and potentially SSCC was evidenced by a reduction in ductility in the SSRT tests and an increase in the hydrogen permeation current values, for almost all welded joints. This was observed with greater intensity for the more acidic test solutions (pH = 3.4), while for the less acidic test solutions (pH = 4.4) little loss of ductility was observed and the hydrogen permeation current remained at values close to zero, indicating little or no permeation of hydrogen through the metal for the testing times applied. The behaviour exhibited by the samples tested in the more acidic solutions was attributed to the dissolution of material from the sample together with hydrogen embrittlement. These results confirmed that the use of sodium thiosulfate solutions to generate H2S, permits the study of phenomena related to SCC in environments containing sulphides.
Guide for Selecting Pressure Control Valves With Actuators Used in Pipeline Applications
Authors: Broyles Jack , Shirt Roger
Published: April 2011

This paper will discuss guidelines for the selection of pressure control valves (PCV) with electro-hydraulic actuators for use in liquid petroleum pipelines. The performance criteria for PCVs functioning in pipeline pressure control applications are distinct from those used in other industrial applications. Also, PCVs required for large diameter petroleum pipeline represent a relatively small number of total control valve applications. For these reasons, general practitioners of control valve selections, typically engineers at EPCs, commonly apply selection strategies that are effective in other industrial applications, but tend to be less so in pipeline applications. This paper will discuss control valve selection criteria including Critical Threshold Capacity, Effective Control Region and Valve Gain Band. Actuator selection criteria discussed in this paper includes Torque Requirements, Speed of Response, and Positioning Resolution.
Code Compliance of a New Metallic Composite Pipeline
Authors: McKinnon Colin , Miles David J. , Burke Raymond N.
Published: April 2011

The composite pipe system, known as XPipe™, is a steel strip laminate technology which uses high-performance adhesives to manufacture a metallic composite pipe. It offers a new method of low cost pipeline construction suitable for onshore gas and oil pipelines in a variety of configurations. The pipe is based on a thin wall liner that provides the fluid containment, the material of which will vary according to service requirements. Fusion bonded epoxy (FBE) coated martensitic ultra-high strength steel strips are then pre-formed and helically wound around the liner to form a laminated high strength reinforcing layer providing the pipe’s hoop strength. These are bonded using an adhesive. Unlike conventional linepipe that is manufactured in a pipe mill away from the construction site, this lightweight composite pipe can be produced at the construction facility using a portable manufacturing line. All components of the manufacturing process fit within standard ISO containers, each weighing between 5 and 15 tonnes. This allows for easy transportation via truck, and handling or shipping. Existing regulations and codes make no specific reference to metal composite pipes. They are mainly written for steel pipe lines with some mention of plastic pipe. The paper presents a comprehensive review of the following US onshore design codes (ASME B31.4/B31.8) and relevant regulations (CFR (DOT) 49 P192 / P195) in order to establish the applicability of these codes for use on XPipe. The paper describes how XPipe meets the code and regulation requirements with regard to safety, design, material, construction, inspection, testing, operation and maintenance. The paper will identify any areas where XPipe does not meet code and regulation requirements and describe the testing and /or design changes that have been made in order to meet the code requirements. The paper will focus on the how the XPipe can meet the practical requirements of these codes. The paper will describe how the qualification testing is being performed in accordance with DNV-RP-A203 Qualification Procedures for New Technology. The qualification testing focuses on how the XPipe meets or exceeds pipeline safety margins with regard to typical failure modes such as yield, burst, facture, fatigue, collapse, etc. This is a continuous process and is being updated after each step using the available knowledge on the status of the qualification.
Comparison of Multiple Crack Detection In-Line Inspection Data to Assess Crack Growth
Authors: Slaughter Mark , Spencer Kevin , Dawson Jane , Senf Petra
Published: April 2011

Ultrasonic inline inspection (ILI) tools have been used in the oil and gas pipeline industry for the last 14 years to detect and measure cracks. The detection capabilities of these tools have been verified through many field investigations. ILI ultrasonic crack detection has good correlation with the crack layout on the pipe and estimating the maximum crack depth for the crack or colony. Recent analytical developments have improved the ability to locate individual cracks within a colony and to define the crack depth profile. As with the management of corroding pipelines, the ability to accurately discriminate active from non-active cracks and to determine the rate of crack growth is an essential input into a number of key integrity management decisions. For example, in order to identify the need for and timing of field investigations and/or repairs and to optimize re-inspection intervals crack growth rates are a key input. With increasing numbers of cracks and crack colonies being found in pipelines there is a real need for reliable crack growth information to use in prioritizing remediation activities and planning re-inspection intervals. So as more and more pipelines containing cracks are now being inspected for a second time (or even third time in some cases), the industry is starting to look for quantitative crack growth information from the comparison of repeat ultrasonic crack detection ILI runs. This paper describes the processes used to analyze repeat ultrasonic crack detection ILI data and crack growth information that can be obtained. Discussions on how technical improvements made to crack sizing accuracy and how field verification information can benefit integrity plans are also included.
Improved Pipeline AUT Inspections Using Laterally-Focused Arrays
Authors: Rigault Sebastien , Carte Mark , Moles Michael
Published: April 2011

Automated ultrasonic inspection of pipeline girth welds during construction relies on well-focused probes. With the arrival of industrial phased arrays, focusing in the vertical direction became straightforward. However, arrays are generally unfocused in the horizontal (circumferential) direction. This can lead to oversizing of small defects, and unnecessary repairs. Modeling was performed to determine the optimum and most cost-effective method of focusing laterally. These results showed that mechanically curving the array in the passive axis provided excellent results. Suitable arrays were manufactured and tested on calibration notches and weld defects. Comparative results will be shown between unfocused and focused arrays. These focused arrays are now a common product on PipeWIZARD.
The Effect of Sample Flattening on Yield Strength Measurement in Line Pipe
Authors: Crone Dave G. , Collins Laurie E. , Bian Yankui , Weber Paul
Published: April 2011

Tensile testing is a key part of the qualification process of Line Pipe. When qualifying pipe products various items are considered when tensile testing; Yield Strength (YS), Ultimate Tensile Strength (UTS), Percent Elongation (%EL), and the Yield Strength to Tensile Strength Ratio (Y/T) are all important. Of these, the YS is the most critical and yet the most sensitive to both preparation and measurement techniques. During the pipe forming process, the base material is plastically formed into a curved shape, and then welded into the final product. The Transverse to Pipe Axis (TPA) tensile specimen removed for testing is curved and must be flattened prior to testing. The flattening process is varied in many facilities and the standards to which testing is conducted are not specific enough to ensure uniformity of procedures. ASTM acknowledges flattening processes and the degree of flatness “may affect test results”, though no guidance is given. This paper will provide an overview of ongoing research efforts, concerning the measurement of the Yield Strength of TPA tensile specimens and its relationship to curvature and flattening methods, prior to testing. By comparing flattened strap tests, to round bar and ring expansion tests, it is shown that the flattened strap test provides a conservative estimate of the actual YS of the pipe.
Sizing Stress Corrosion Cracks Using Laser Ultrasonics
Authors: Rehman Hamood , Klein Marvin , Kania Richard , Rapp Steve , McNealy Rick , Fingerhut Martin , Ansari Homayoon
Published: April 2011

Integrity management decisions related to operating energy transmission pipelines affected by Stress Corrosion Cracking (SCC) represent a formidable challenge to the pipeline industry. Effective management of SCC damage requires the development of tools and technology to identify the occurrence of SCC and to assess the impact of the SCC on pipeline integrity. Development of practical non-destructive evaluation (NDE) solutions for the measurement and evaluation of SCC, including crack depths, is difficult due to the complexity of crack shapes and their inter-relationship and distribution within crack colonies. Laser ultrasonics is an inspection technology using laser beams to generate and detect ultrasonic waves in the pipeline wall to be inspected. Unlike conventional ultrasound, it has a large bandwidth and the beams have a very small (∼0.5mm) footprint. These characteristics make it ideally suited for application as a depth sizing tool for SCC in pipelines. Through a collaborative research project jointly funded by the US Department of Transportation, Pipeline and Hazardous Materials Safety Administration (PHMSA) and PRCI, Applus RTD and its research partners have conclusively shown that laser ultrasonic inspection technology using the Time of Flight Diffraction (TOFD) technique reliably and accurately measures the depth of SCC. In addition, this technique may also be applicable to measuring the depth of other cracks such as seam weld anomalies. The project included the development of a prototype NDE inspection tool for measurement of SCC, and recently culminated with a series of full-scale demonstrations of the tool. This paper describes the detailed technical work conducted to support the development of the tool and validation of the TOFD technique for sizing the depth of SCC. In addition, this paper presents the preliminary results of work on a closely related project that builds on the technology described above to produce an integrated approach and tool for mapping, sizing, and evaluating SCC that filters significant (i.e., deep) cracks from more benign cracks within an SCC colony.
Ultrasonic Crack-Detection in Demanding Pipeline Environments and Low Diameter Pipes
Authors: Baumeister Marc , Bouaoua Nourreddine , Woltermann Frank , Hennig Thomas , Berlekamp Maria , Beuker Thomas
Published: April 2011

Ultrasonic crack detection represents a reliable and accepted inline inspection technology for the application in liquid media. The technology is long standing and considered as industry standard [1–3]. As a result of various demands, e.g. increased temperature levels above 70°C, high pressures exceeding 100 bars and medium types (e.g. heavy crude oil) with inherently high damping and temperature dependency of the damping characteristic the complexity can be primarily found within the bounding conditions. The reduction of inner pipeline diameter, e.g. below 120 mm, represents a further increase of degree of complexity. This paper gives access to the design and development approach chosen by ROSEN for ultrasonic crack detection tools and the case of pipelines with an outer diameter ranging from 6″ to 8″. All previously mentioned issues and requirements are considered. The mechanical design of the ultrasonic crack detection tools is described.
Tensile Strain Capacity of X80 Pipeline Under Tensile Loading With Internal Pressure
Authors: Igi Satoshi , Sakimoto Takahiro , Suzuki Nobuhisa , Muraoka Ryuji , Arakawa Takekazu
Published: April 2011

This paper presents the results of experimental and finite element analysis (FEA) studies focused on the tensile strain capacity of X80 pipelines under large axial loading with high internal pressure. Full-pipe tensile test of girth welded joint was performed using high-strain X80 linepipes. Curved wide plate (CWP) tests were also conducted to verify the strain capacity under a condition of no internal pressure. The influence of internal pressure was clearly observed in the strain capacity. Critical tensile strain is reduced drastically due to the increased crack driving force under high internal pressure. In addition, SENT tests with shallow notch specimens were conducted in order to obtain a tearing resistance curve for the simulated HAZ of X80 material. Crack driving force curves were obtained by a series of FEA, and the critical global strain of pressurized pipes was predicted to verify the strain capacity of X80 welded linepipes with surface defects. Predicted strain showed good agreement with the experimental results.
Holistic Data Approach and Results: How the Latest Enhancements in ILI Technology Benefit Engineering Criticality Assessments
Authors: Dawson Jane , Bluck Martin , Fisher Ian , Sutherland Jeff
Published: April 2011

Recent enhancements in the Magnetic Flux Leakage (MFL) in-line inspection (ILI) technology has enabled more reliable detection and more accurate reporting of a greater range of anomaly types than ever before, though the true value rests with what the integrity engineering specialists are able to do with the enhanced information to translate it into an actionable Integrity Management Plan. This paper describes how the enhanced information can be used in engineering criticality assessments and the benefits this brings to the operator in the form of integrity management decision-making with higher confidence, reduced investigation and repair costs and less operational disruption from ILI activity. This paper demonstrates how the new holistic data approach brings a seamless transition from raw inspection data to an actionable integrity report, with more advanced assessment of metal loss and mechanical damage data. Engineering criticality assessments are used to illustrate how the enhanced ILI information is used and how the results benefit integrity management decision-making. For example: • Fitness for Service corrosion assessment determines the immediate and future integrity needs by evaluating the criticality of corrosion anomalies identified during an ILI. Taking account of the reduced ILI uncertainty associated with the new MFL technology, the immediate and short-term response schedules can be developed with higher confidence than before and long term remediation activities and re-inspection intervals can be truly optimized. • For re-inspections, the focus is on the determination of accurate corrosion growth rates. Using signal-matching techniques, active corrosion sites can be identified and the corrosion growth rates estimated with high confidence. This provides the basis for optimizing the long-term remediation activities and re-inspection intervals. • The ability to account for coincidental anomalies and loading conditions, e.g., the occurrence of bending strains resulting from loss of ground support coincident with girth weld anomalies, circumferential corrosion or denting/buckling are important integrity considerations that influence how the anomalies are assessed. • Improved Caliper sensor resolution enables the dent profile to be visualized more accurately leading to improvements in the way dents are assessed, i.e. using strain-based methods. Reliable detection of gouging within dents is an essential component for establishing the cause and assessing the severity of dents and has always been challenging for conventional MFL ILI tools. This enhanced MFL technology enables metal loss within dents to be detected and viewed via a Triaxial magnetic sensor system, providing more information of the nature of the metal loss within the dent.
Development of Guidelines for Parallel Pipelines
Authors: Acton Michael R. , Jackson Neil W. , Jager Eric E. R.
Published: April 2011

Due to the increasing demand for natural gas in many locations, there is often a need to increase the capacity of existing and future gas transmission pipeline networks. In some situations, there may be a possibility of increasing the operating pressure (e.g. uprating), but in others there may be no alternative but to lay new pipelines, often along the same route as an existing pipeline. If one pipeline fails in this situation, it is possible that a second parallel pipeline may also fail as a result. However, there is also increasing pressure on the use of land and therefore the minimum separations with which pipelines may be laid and operated safely when in parallel to other pipelines need to be considered. This paper describes work carried out as a collaborative project supported by gas transmission pipeline operators to provide guidance on the likelihood of failure of a pipeline, for a range of different conditions, following failure of an adjacent pipeline. A framework has been developed that identifies the sequence of events that could lead to failure of a parallel pipeline, including the possibility of escalation from a leak (or puncture) to a full bore rupture. Work has been carried out including large scale experiments and CFD (Computational Fluid Dynamics) modelling to enable the critical processes in the framework to be quantified. This methodology has been used to produce general guidelines for parallel pipeline assessments, in order to support the design of new parallel pipeline installations. The methodology has been developed specifically for parallel natural gas transmission pipelines. However, the principles are relevant to parallel pipelines transporting other substances, and consideration is given to how the methodology may be adapted for such circumstances. The methodology provides input to any risk assessments of parallel pipeline installations, to quantify the possible contribution to the failure frequency from escalation. General guidance developed using the methodology presented in this paper, has recently been included in the recommendations for steel transmission pipelines, IGEM/TD/1 (Edition 5), published by the Institution of Gas Engineers and Managers. However, where general recommendations are not achievable, the methodology may be applied to take site and pipeline-specific factors into account.
Limit Load and Reference Stress for Curved Wide Plates
Authors: Hertele´ Stijn , De Waele Wim , Denys Rudi , Van Wittenberghe Jeroen , Verstraete Matthias
Published: April 2011

Curved wide plates are a valuable tool in the assessment of defective pipeline girth welds under tension. Throughout the years, Laboratory Soete collected an extensive database of curved wide plate test results. In an effort to investigate these results through FAD analysis, the authors recently developed a reference stress equation for curved plates. The approach followed is similar to the development of the Goodall and Webster equation for flat plates. This paper elaborates finite element analyses of the equation’s capability to predict plastic collapse. It is found that, although overestimated, the influence of plate curvature is correctly predicted in a qualitative way. For all simulations, the curved plate reference stress equation produced conservative estimations. This indicates that the proposed equation is suited to safely predict the plastic collapse of defective pipeline girth welds. An experimental validation is underway.
Early Generation Pipeline Girth Welding Practices and Their Implications for Integrity Management of North American Pipelines
Authors: Amend Bill
Published: April 2011

The characteristics of early generation pipelines (i.e., “vintage pipelines”) reflect the rapid evolution of pipeline materials, welding, and inspection practices that occurred during the first half of the twentieth century. The diverse range of welding and inspection practices and the unique characteristics of early generation pipeline welds can influence pipeline segment risk ranking and integrity assessment. This paper summarizes some of the key findings regarding girth weld fabrication, performance and integrity assessment determined during the course of a literature review performed as part of a recently completed PRCI project. Some of the key findings include: 1. The failure rate of early generation girth welds is low, particularly for welds made by arc welding and for welds made after 1930. This is especially true when considering the rate of catastrophic failures (ruptures or nearly full circumference breaks). Welds are typically reported to be responsible for no more than about 6% of significant pipeline failures. 2. Pipeline girth welds are unlikely to fail unless subjected to axial strains that far exceed the strains related to internal pressure alone. Girth welds containing significant workmanship flaws are likely to be resistant to failure at stresses less than the pipe yield strength unless the welds are undermatched and/or are susceptible to brittle fracture initiation. Common mechanical tests, such as Charpy impact testing or CTOD tests may result in grossly conservative indications of the likelihood of brittle fracture occurring in vintage girth welds. 3. A diverse range of early generation girth weld joint designs exist, some of which hamper effective inspection using ILI or represent challenges to effective assessment using conventional fitness-for-service or engineering critical assessment methods (ECA). Effective probabilistic ECA is further hampered by wide variations in workmanship and difficulty in determining mechanical property distributions. 4. Pipeline vintage is a poor indicator of girth weld integrity. Pipeline girth weld integrity is more likely related to project-specific inspection and testing practices than to pipeline age. Welding and inspection practices evolved very quickly in the 1920s through the 1940s and a wide range of practices were used on different pipelines that were constructed in the same time period. Girth weld integrity is typically highest for post 1930s pipelines that were subjected to radiographic inspection.
Guidelines for Production of API Pipelines Steels Suitable for Hydrogen Induced Cracking (HIC) Service Applications
Authors: Stalheim Douglas G. , Hoh Bernhard
Published: April 2011

Worldwide oil and natural gas reserves can be classified as either sweet or sour service. The sour service classified oil and natural gas reserves contain some level of H2S making the product flowing through a steel pipeline corrosive. Due to this, the majority of the oil and natural gas reserves that have been drilled are of the sweet service nature. However as demand continues and supplies change, many of the remaining oil and natural gas reserves contain the H2S component and are of a sour service nature. These oil and natural gas reserves containing the H2S component through a corrosion mechanism will allow for diatomic hydrogen — in the presence of moisture — to disseminate to monatomic hydrogen and diffuse into the pipeline steel microstructure. Depending on the microstructure and level of cleanliness the monatomic hydrogen can become trapped at areas of high residual stress, recollect to diatomic hydrogen and creating partial pressures that exceed the tensile strength of the steel resulting in cracking. Therefore transmission pipelines are being built to transport sour service oil or natural gas requires steels with hydrogen induced cracking (HIC) resistance. Alloy designs, steel making processing, continuous casting, plate or strip rolling, pipe forming, and last not least corrosion testing are all key components in producing pipeline steels that are resistant to HIC applications and meeting the NACE TM0284 specifications. However, producing steels that have good HIC performance do not necessarily meet other mechanical property requirements such as strength and YT ratios. Balance has to be achieved to meet not only the HIC requirements but the other required mechanical properties. Mastering this complex HIC process poses a serious challenge to pipe producers and their primary material suppliers. The capability of producing HIC steel grades according to critical specifications and/or standards clearly distinguishes excellent steel producers from good steel makers. This paper will discuss the basics of the hydrogen induced cracking phenomenon, the requirements of the NACE TM0284 specification and give guidelines for steel production of API pipeline steels that not only can meet the specification requirements the NACE testing but also fulfill the other mechanical property requirements.
Microstructure and Mechanical Property Performance of Commercial Grade API Pipeline Steels in High Pressure Gaseous Hydrogen
Authors: Stalheim Douglas , Boggess Todd , San Marchi Chris , Jansto Steve , Somerday Brian , Muralidharan Govindarajan , Sofronis Petros
Published: April 2011

The continued growth of the world’s developing countries has placed an ever increasing demand on traditional fossil fuels. This increased demand for fossil fuels has lead to increasing research and development of alternative energy sources. Hydrogen gas is one of the potential alternatives under development. It is anticipated that the least expensive 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. Consequently, the current pipeline infrastructure used in hydrogen transport is typically operated in a conservative fashion, in particular lower operating pressures, lower strength steels, and heavier pipe wall thicknesses. 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 depends on the microstructure of the steel. An understanding of the relationship of mechanical property degradation of a given microstructure on exposure 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 suitablity for transporting hydrogen. A project to evaluate four commercially available pipeline steels alloy/microstructure performance in the presences of gaseous hydrogen has been funded by the US Department of Energy along with the private sector. The microstructures of four pipeline steels were characterized and tensile testing was conducted in gaseous hydrogen and helium at pressures of 5.5 MPa (800 psi), 11 MPa (1600 psi) and 20.7 MPa (3000 psi). Based on reduction of area, two of the four steels that performed the best across the pressure range were selected for evaluation of fracture and fatigue performance in gaseous hydrogen at 5.5 MPa (800 psi) and 20.7 MPa (3000 psi). This paper describes the work performed on four commercially available pipeline steels in the presence of gaseous hydrogen at pressures relevant for transport of hydrogen in pipelines. Microstructures and mechanical property performances are compared. In addition, recommendations for future work related to gaining a better understanding of steel pipeline performance in hydrogen service are discussed.