bluuebunny/crossref_metadata_2025 huggingface dataset:
Development of Line Pipes With Improved Behavior in Severe Sour Environment
Authors: Veselov I. N. , Pyshmintsev I. Yu. , Zhukova S. U. , Pumpyanskyi D. A. , Antonov V. G.
Published: October 2008

A low-carbon low-alloy steel corresponding to Grade X42 according to API SPEC 5L and resistant to hydrogen sulfide environments has been developed. Heat treatment conditions have been optimized. The heat treatment recommended provides for the corrosion resistance and desired level of finished product mechanical properties. Welded joints of pipes made of the developed steel have successfully passed benchmark tests carried out at Astrakhan gas-condensate field.
PETROBRAS Criteria for Acoustic Emission and Fracture Mechanics Relationship
Authors: Soares Sergio Damasceno , Rebello Joa˜o Marcos A.
Published: October 2008

During the last years, PETROBRAS has used acoustic emission technique as an inspection tool. In this period, the acoustic emission concept has changed from a revolutionary technique to a global inspection technique with the aim of indicating areas to complementary inspection. In the last years more than 600 acoustic emission tests were done in equipments like pressure vessels, reactors, tanks, spheres, and etc. In 2002, the results of acoustic emission tests and nondestructive tests done on these equipment were collected to build a database in the PETROBRAS environment. Analysis made in this database has shown that exists a clear relationship between acoustic emission and the severity of flaws.
Pipeline Geohazards Unique to Northern Climates
Authors: Tart Rupert G.
Published: October 2008

Pipelines in northern climates can be impacted by geohazards that are unique to cold regions. Some of these include frost heave, thaw settlement, solifluction, icings, glaciers, ice-rich slopes, and others. This paper will discuss most of these geohazards as they have been monitored, mitigated, and managed along the Trans Alaska Pipeline (TAPS) and other pipelines in Alaska and Russia. Early analyses of frost heave and thaw settlement of piles concluded that frost heave and thaw settlement would be controlled by installing passive heat removal devices (heat pipes). In permafrost areas heat pipes have generally worked well. In unfrozen terrain or discontinuous permafrost the heat pipes have not been able to maintain stability. Examples of each of these situations will be discussed. Steep rolling terrain makes up a significant part of the TAPS route. Some of the slopes are in permafrost and others are in thawed ground. For the past 15 years, surveillance and monitoring of some of the slopes along the pipeline route has documented the response of slopes in frozen ground. Warmer (that is near 0 degrees C) ice-rich slopes can creep. An example of this is documented on a slope instrumented with inclinometers and thermistors. Other slope movements related to pore pressure increases caused by active layer containment of unfrozen groundwater flows will be discussed. The impact of solifluction zones on pipeline construction and routing will be addressed as it has been managed along the TAPS. Other near surface slope movements that appear to be similar to solifluction have been observed along the pipeline right-of-way on the workpad. This paper will address an interrelationship of these observed slope behaviors. In doing this the interaction of slope seeps and the freeze front as it forms in fall and then recedes in spring and summer is compared to observations of engineered projects. Icings can be observed in several locations along TAPS. In some cases these can be related to slope movements. In other cases the icings have reached the aboveground and caused maintenance issues. TAPS was designed to avoid future surges of several large glaciers. In most years these glaciers have retreated and have not been a significant issue. A recent large earthquake caused a landslide on the largest glacier near TAPS and resulted in some review of the activity on that glacier. In 2002 a large earthquake centered near TAPS caused liquefaction in some areas, breakage of ice in lakes in some locations, and sand boils very close to the pipe. These observations will be related to the thinly frozen active layer over a deep talik during the earthquake.
Induction Hot Bending and Heat Treatment of 20” API 5L X80 Pipe
Authors: Batista Gilmar Zacca , Naschpitz Leonardo , Hippert Eduardo , de Souza Bott Ivani
Published: October 2008

The present work discusses the effect of the induction hot bending process on the microstructure and the mechanical properties of an API 5L X80, 20” pipe produced by the UOE process. The key characteristic of the pipe was the manufacturing process of the steel plate, involving thermomechanical controlled rolling without accelerated cooling. The pipe bending was carried out applying local induction heating followed by water quenching and a further temper heat treatment which was applied to the curved section. The methodology of analysis compared the curved section with the original body pipe (tangent end), taking into account dimensional analysis, microstructural evaluation and mechanical tests which included Charpy-V impact, tensile and microhardness. A significant microstructural change and decrease, not only in the transition temperature, but also in the yield strength, occurred after induction bending. This reduction resulted in a tensile strength below the standard requirements. The subsequent tempering heat treatment applied to the curved section produced an increase in the yield strength to achieve the API 5L requirements for this class of steel.
A New Probabilistic Methodology for Undertaking External Corrosion Direct Assessment
Authors: Francis Andrew , McCallum Marcus , Van Os Menno T. , van Mastrigt Piet
Published: October 2008

External Corrosion Direct Assessment (ECDA) has now become acknowledged, by the Office of Pipeline Safety (OPS) in North America, as a viable alternative to both in-line inspection (ILI) and the hydrostatic pressure test for the purpose of managing the integrity of high pressure pipelines. Accordingly an ECDA standard is now in existence. The essence of ECDA is to use indirect above ground survey techniques to locate the presence of coating and corrosion defects and then to investigate some of the indications directly by making excavations. However, one of the problems of above ground survey techniques is that they do not locate all defects and are susceptible to false indication. This means that the defects will not be present at all indications and that some defects will be missed. In view of the limitations of above ground survey techniques the ECDA standard requires that at least two complimentary survey techniques should be used. The selected survey techniques will depend on the nature of a particular ‘ECDA segment’, taking account of the surface characteristics. However, in many situations the surveys will include a coating survey and a corrosion survey. In general the outcome from these two surveys will be NH locations at which just the coating survey gives an indication, NC locations at which just the corrosion survey gives an indication and NHC locations at which both surveys give an indication. This paper presents a new probabilistic methodology for estimating the distributions of the actual numbers of coating and corrosion defects, taking account of the outcomes of the surveys and the probabilities of detection and false indication of both techniques. The method also shows how the probabilities of detection and false indication are updated depending on what is found during the excavations and the distributions of the numbers of remaining corrosion and coating defects are subsequently modified. Based on a prescribed repair criterion the analysis is used to determine the probability that at least one remaining corrosion defect will exceed the repair criteria. As excavations are sequentially performed the probability naturally reduces. The attainment of an acceptably low probability is used as a trigger to terminate the excavation programme. A detailed description of the development of the method is given in this paper and the application is illustrated through a simple numerical example. A description of how the method is used to build a Direct Assessment module for a pipeline integrity management system is described in an accompanying paper.
Ductile Fracture Resistance Modeling Approach in Two High Grade Steels
Authors: Pussegoda L. N. , Fredj A. , Dinovitzer A. , Horsley D. , Carlson D.
Published: October 2008

Recent developments in ductile fracture resistance measures in high grade steels in the pipeline industry include the crack tip opening angle (CTOA) and “steady state” fracture propagation energy, using 3-point bend specimens. The CTOA has been found to be a function of specimen ligament size. Alternatives would be “steady state” fracture propagation energy, critical fracture strain and adoption of damage mechanisms. This paper focuses on modeling approaches for crack propagation using damage mechanisms. The tension test is used to “calibrate” the damage model parameters and applied to the crack propagation in a 3-point bend specimen in candidate high grade steels. The effects of using parameters developed from tension test and extending to a 3-point bend crack propagation scenario is discussed.
Improvement in Compliance Reporting for Project Management at TransCanada
Authors: Corsino Grace
Published: October 2008

TransCanada PipeLines Limited operates under several provincial and federal regulatory authorities. As such, the company is required to submit to a range of compliance reporting. This paper will discuss the key commitment requirements that TransCanada faces and how the company is streamlining its business processes to facilitate timely and effective response. Furthermore, the paper will include a discussion on TransCanada’s proactive approach on adopting a unique “single method” on internal audits and 30 day compliance reporting that has saved time in the production of regulatory communication.
Residual Strength of Corroded Pipelines Under External Pressure: A Simple Assessment
Authors: Netto T. A. , Ferraz U. S. , Botto A.
Published: October 2008

The loss of metal in a pipeline due to corrosion usually results in localized pits with various depths and irregular shapes on its external and internal surfaces. The effect of corrosion defects on the collapse pressure of offshore pipelines was studied through combined small-scale experiments and nonlinear numerical analyses based on the finite element method. An extensive parametric study using 2-D and 3-D numerical models was carried out encompassing different defect geometries and their interaction with pipe ovalization. This paper briefly summarizes these results, which are subsequently used to develop a simple procedure for estimating the collapse pressure of pipes with narrow defects.
Evaluation of the Effect of Yield to Tensile (Y/T) Ratio on the Structural Integrity of Offshore Pipeline by Limit State Design Approach
Authors: Mannucci Gianluca , Malatesta Giuliano , Demofonti Giuseppe , Tivelli Marco , Quintanilla Hector , Izquierdo Alfonso , Cumino Giuseppe
Published: October 2008

Nowadays specifications require strict Yield to Tensile ratio limitation, nevertheless a fully accepted engineering assessment of its influence on pipeline integrity is still lacking. Probabilistic analysis based on structural reliability approach (Limit State Design, LSD) aimed at quantifying the yield to tensile strength ratio (Y/T) influence on failure probabilities of offshore pipelines was made. In particular, Tenaris seamless pipe data were used as input for the probabilistic failure analysis. The LSD approach has been applied to two actual deepwater design cases that have been on purpose selected, and the most relevant failure modes have been considered. Main result of the work is that the quantitative effect of the Y/T ratio on failure probabilities of a deepwater pipeline resulted not so big as expected; it has a minor effect, especially when Y only governs failure modes.
Ultrasonic Inline Inspection of the Moomba to Sydney Pipeline
Authors: Ohl Stephen P. , Allison Robert E.
Published: October 2008

For the majority of Australian gas pipelines it is not practical to remove them from service for extended periods of time. This rules out hydrostatic testing as a means of confirming the integrity of older pipelines including those that may contain Stress Corrosion Cracking (SCC). The Moomba to Sydney pipeline (MSP) at 864 mm (34 inch) nominal bore and 1299 km (807 miles) in length is the largest diameter onshore gas transmission pipeline in Australia. Commissioned in 1976, it has a history of susceptibility to SCC and, in 1982, six years after commissioning, suffered a SCC initiated rupture. Since this time the pipeline owners have operated and maintained the pipeline to ensure no further SCC initiated failures. Maintenance for SCC has included a targeted excavation program which, between 2000 and 2004, found significant SCC colonies. This created the need to develop a more comprehensive approach to locate and identify every significant SCC colony in the pipeline. Several options were considered but the one that was selected as best meeting the performance criteria was the use of an ultrasonic intelligent pig running in a liquid medium. This pigging operation had to be carried out while the pipeline continued in operation with minimal disruption to gas transmission operation. This had never been done before in Australia. The initial intelligent pigging program of the first 162 km (101 miles) of the pipeline was conducted in early 2005 with an additional 292 km (181 miles) pigged in early 2006. This paper provides information on the approach taken to overcome the many technical, operational and commercial challenges of this operation. Water was chosen as the liquid medium and a major issue was the introduction and removal of water from the pipeline while it remained in operation. This could not have been achieved without the co-operation of producers, shippers, network owners, network operators, technical regulators and contractors. The paper also looks at the how the results obtained from the pigging will be used to enable the SCC to be managed in a safe and efficient manner and confirming the safety and fitness for purpose of the MSP now and into the future.
Design of Fast Portable Detection Instrument for Buried Pipeline Coating Defects
Authors: Zhang Yu , Jin Shijiu , Chen Shili , Tan Dongjie , Wang Likun
Published: October 2008

Due to large repair workload and cost, the detection of coating has a great guidance to a major overhaul of buried pipelines. Direct current voltage gradient (DCVG) and close interval potential survey (CIPS) techniques have already been widely used in this area and the theories are introduced in this paper. Based on the above two detection principles, a set of detection instrument for coating defects of buried pipelines is developed, and the detailed hardware and software designs of the instrument is also provided. In this instrument, pipe/soil potential is used to detect coating defects and IR drop (the product of soil current and resistance) is eliminated during potential measurement using instantaneous CP (cathode protection) current cut method. The detection results saved in Flash can be displayed on LCD of the instrument or transferred to the computer for graph plotting. Through the field application examples, it is indicated that the device designed in this article has a very high precision in defects positioning and a broad prospect of application.
Assessment of Corrosion Defects in Old, Low Toughness Pipelines
Authors: Martin Michael , Andrews Robert (Bob) , Chauhan Vinod
Published: October 2008

Corrosion metal loss in one of the major damage mechanisms to transmission pipelines worldwide. The remaining strength of corroded pipe subjected to internal pressure loading has been extensively researched and guidelines for assessing corrosion are well defined. Methods including ASME B31G, RSTRENG and LPC have been developed, validated and matured to the extent that they are now incorporated in standards and regulatory requirements. However, these methods are based on the assumption that the pipe fails via a ductile mechanism, i.e., the line pipe material has sufficient toughness to prevent a toughness dependent failure. This limits the application of the existing methods to materials that have sufficient toughness. It is possible that some older pipelines operate with the material in the ductile / brittle transition region of the Charpy transition curve, or even on the lower shelf. It is also possible that under fault conditions, a pipeline normally operating on the upper shelf could be temporarily in the transition region. In these circumstances, existing assessment criteria may be non-conservative. At present there are no rigorous criteria available for assessing corrosion defects in low toughness pipe. This paper presents an approach for removing the uncertainty in the use of existing methods for assessing corrosion defects in older, low toughness pipelines based on the Beremin approach to brittle cleavage fracture. Comparison of the Beremin results with existing assessment methods allows an ‘effective transition temperature’ to be defined as the temperature at which the existing method is no longer conservative. The results suggest that, for the corrosion defects investigated, the effective transition temperature is sufficiently low that existing assessment methods will remain conservative.
Low Application Temperature Graded Structure Polyolefin Coating System Based on a Next Generation FBE for Strain-Based Design Pipelines Using High Strength Steel
Authors: Edmondson Stephen J. , Wong Dennis T. , Steele Robert E.
Published: October 2008

Pipelines combining strain-based design with the use of thin walled, high strength steel (X80 or higher) present a significant challenge in terms of the availability of suitable coating systems. FBE-based coatings typically require the pipe to be heated to temperatures in the range of 230°C to 250°C for a period of up to 10 minutes in order to achieve optimum properties. The problem is that some of the key properties of such steels can change when they are subjected to such a heat cycle, resulting in a reduction in the tensile elongation at yield, a key requirement with strain-based design pipelines. When such pipelines are being constructed in remote areas, such as Northern Canada, there is the additional requirement that the coating must be robust enough to withstand transportation, handling and construction damage, and be bendable to temperatures as low as −50°C. Graded Structure Polyolefin Systems (GSPO) such as Bredero Shaw’s High Performance Composite Coating (HPCC) have established an excellent track record on pipelines constructed in very cold conditions through very rough terrain. However, such coatings are historically based on conventional fusion-bonded epoxy coatings designed for optimum performance when applied to pipes heated to 230 to 250°C. This paper describes a new version GSPO coating which can be produced without having the pipe temperature exceed 200°C at any point in the process, and which provides performance virtually identical to that of the standard GSPO product. It is the result of a cooperative development between Bredero Shaw and DuPont Powder Coatings, and is based on a new generation of FBE which can be processed at temperatures as low as 175°C with very little sacrifice in resistance to adhesion, as characterized by hot cathodic disbondment. Because the FBE has primary responsibility for providing corrosion resistance, the performance of the new generation FBE applied at low application temperatures was first compared to that of well-established FBE applied at their recommended application temperatures. Cathodic Disbondment (CD) was selected as the key performance test for adhesion because it simulates field conditions for disbonding of a coating from a pipeline with impressed current cathodic protection. Because the measurement of disbondment is on a continuous numerical scale, statistical analysis is possible. The new generation FBE coating performs significantly better in CD testing than conventional FBE when applied at lower application temperatures. Its performance is comparable to the best conventional FBE when applied at 240°C. This performance is maintained in the Low Application Temperature GSPO coating.
Pipeline Inspection With the High Resolution EMAT ILI-Tool: Report on Full-Scale Testing and Field Trials
Authors: Klann Martin , Beuker Thomas
Published: October 2008

In succession of a research project to develop an EMAT in-line inspection technology for the detection of stress corrosion cracking (SCC) and disbonded coating, a 16” EMAT inspection tool was manufactured and tested. This 16” EMAT Crack Detection (ECD) Tool establishes a new high-resolution approach to effective and accurate crack inspection technology especially for gas lines. The performance of this tool was tested on several pipe samples containing natural SCC as well as artifical anomalies and laminations. Furthermore, a field test is currently being conducted, which will detail the tools performance under operational conditions. The new technology will be compared to the results from the established Magnetic Flux Leakage inspection (MFL) technology. EMAT inspection technology, originally designed for detection of SCC, is also sensitive to areas of disbonded coating, other crack-like features, and anomalies like gouging and channeling. To distinguish the different types of pipeline threats, a qualitative defect sizing process is under development incorporating the EMAT data and the information from the other in-line inspection technologies. Following an introduction into EMAT guided wave theory, data from a series of full-scale tests obtained with 34” prototype sensors and the complete 16” ILI-EMAT tool, will be presented. The inspection tool itself, as well as the process for evaluating the recorded data, are undergoing continuous improvements. This paper will discuss the development status of these technologies.
The Evolution and Determination of Mechanical Properties During the Manufacturing Process of High Strength Spirally Welded Pipe
Authors: Chen Xiande , Collins Laurie , Hamad Fathi , Bai Dengqi
Published: October 2008

During the development of high strength and high toughness spirally welded pipe with improved weld heat affected zone toughness, the evolution of the mechanical properties were studied by testing at different stages of the manufacturing process. The mechanical properties were measured in the as-welded condition after the spiral seam welding, after the hydrostatic test and after the aging cycle simulating the external pipe coating process. The tensile properties of the pipe body in the transverse-to-pipe-axis (TPA) orientation, as required by the CSA Z245.1 and API 5L standards, were determined using different test methods and different specimen geometries, such as flattened strip specimen, non-flattened round-bar specimen and ring-expansion specimen. The investigation results provided some insights into the development of the mechanical properties of the final pipe products and the methods for more realistically and reliably determining the tensile properties of the pipe along the circumferential direction.
Effect of Transitions in the Water Table and Soil Moisture Content on the Cathodic Protection of Buried Pipelines
Authors: King Fraser , Given Russell , Worthingham Robert G. , Van Boven Greg
Published: October 2008

Buried pipelines can be subject to transitional environments due to changes in soil type or moisture content. Changes in the height of the water table, for example, will affect not only the availability of water but also the access of oxygen to the pipe surface. Transitions between different soil types will also result in different exposure conditions for different parts of the pipe. These variations can affect the distribution of potential on the pipe surface and the ability of the CP system to provide adequate protection. A combination of laboratory-scale soil box tests and field measurements on operating pipelines has been used to study the effect of varying moisture content and water level on the level of cathodic protection and on pipe-depth environmental conditions. In both laboratory tests and field trials, the degree of protection depends on the availability of cathodic reactants (O2 and/or H2O). Ingress of O2 results in a positive shift in potential as more current is required to electrochemically reduce the oxidant and the pipe is less easily polarized. Under some circumstances the ingress of water has the same effect. Although more aerobic conditions lead to more-positive potentials the pipe is not necessarily less well protected. In many dry and/or high resistivity soils the pipe surface may well be passive because of the high interfacial pH and/or high O2 concentration.
Crack Tip Opening Angle: Measurement and Modeling of Fracture Resistance in Low and High Strength Pipeline Steels
Authors: Darcis Ph. P. , Kohn G. , Bussiba A. , McColskey J. D. , McCowan C. N. , Fields R. , Smith R. , Merritt J.
Published: October 2008

Crack tip opening angle (CTOA) is becoming one of the more widely accepted properties for characterizing fully plastic fracture. In fact, it has been recognized as a measure of the resistance of a material to fracture, in cases where there is a large degree of stable-tearing crack extension during the fracture process. This type of steady-state fracture resistance takes place when the CTOA in a material reaches a critical value, as typically occurs in low-constraint configurations. Our current research has applied the CTOA concept as an alternative or an addition to the Charpy V-notch and the drop weight tear test (DWTT) fracture energy in pipeline characterization. A test technique for direct measurement of CTOA was developed, using a modified double cantilever beam (MDCB) specimen. A digital camera and image analysis software are used to record the progression of the crack tip and to estimate CTOA using the crack edges adjacent to the crack tip. A steady-state CTOA has been successfully measured on five different strength grades of gas pipeline steel (four low strength grades and one high strength grade: X100). In addition, two-dimensional finite element models (2D FEMs) are used to demonstrate the sequence of the fracture process and the deformation mechanisms involved. The CTOA measurements and models are correlated and agree well.
SCC Management and Integrity Planning in a Gas Pipeline
Authors: Katz David , Limon Sergio , Gao Ming , McNealy Rick , Krishnamurthy Ravi , McCann Roger
Published: October 2008

Stress Corrosion Cracking (SCC) is a major integrity management concern for many gas and oil pipeline operators. Predictive models for Stress Corrosion Crack growth were developed using laboratory test data from the mid 1970’s, and limited inspection data and excavation measurements from the early 1990’s. Extensive efforts continue to be made to develop strategies for a better management of the SCC problem. In this paper, a study of crack growth rates was conducted on the Williams 16-inch gas pipeline using data from two consecutive in-line crack detection tool runs and direct field measurements. Findings from this study provide a direct measurement of crack growth rates for ILI crack features with depths ranging from 12.5%wt to 40%wt. Future integrity of the pipeline was assessed. The integrity management strategies could be further refined using the calculated crack growth rate, field excavation data and fracture mechanics based API 579 FAD approach.
Regulation of a Natural Gas Distribution Network in a Developing Country: From Conception to Implementation
Authors: Fernandez Victor M.
Published: October 2008

The paper will discuss the challenges and key success factors needed to development and operate a natural gas distribution network. This discussion will include the development of the regulatory model — performance-based vs. prescriptive. It will examine the development of the actual regulations, compliance and oversight strategies. In addition the paper will discuss the various existing regulatory and standards models throughout the world and how the best fit components were incorporated into the model. The paper will examine the incorporation of a Quality Management System integrated by an Integrity Management Program and a Quality Services Program. In addition it will highlight the social economic and environmental challenges encounter implementing a “culture of gas” in a developing country.
Effect of Pre-Deformation on Fatigue Crack Propagation Life of X60 Pipeline Steel
Authors: Zhao Xinwei , Luo Jinheng , Wang Rong , Zheng Maosheng , Dong Baosheng
Published: October 2008

It is impossible to keep oil and gas pipeline free from defects in fabrication, installation and serving processes. Mechanical damage is one of import causes of pipeline failure accidents. Mechanical damage might endanger the safety of pipelines and even shorten their service life. Pre-tensile deformation of X60 steel is employed to experimentally simulate the influence of dents on the fatigue crack initiation life. The investigation indicates that the fatigue crack propagation life of pre-deformed X60 pipeline steel can be predicted using a previously proposed equation, i.e., da/dN = B(ΔK − ΔKth)2. The threshold ΔKth for fatigue crack propagation decreases with the pre-deformation. The fatigue crack propagation coefficient B increases with the pre-deformation. So pre-deformation accelerates fatigue crack propagation and shortens fatigue life. The result is expected to be beneficial to the understanding of the effect of dents on the safety of pipelines and fatigue life prediction.
A New Method for Evaluating the Performance of Coatings on Pipelines
Authors: Liu Bing , He Renyang , Zhang Hong , Wang Xiao-Lin
Published: October 2008

In general, Rg Value, Y value and holiday density can be used to evaluate the performance of the coating deposited on the buried steel pipelines. However, the evaluation may be misleading when a single parameter is used. A new combination method for assessing the performance of the coating on the steel pipelines is developed in this paper. Using this approach, Rg Value, Y value and holiday density play appropriate role on the assessment. Some new modules are presented in this approach, including current distributary module, holiday module, intelligent critical curve of AC attenuation. Additionally, a computer program is compiled that can finish data processing of AC attenuation automatic, and the result report can be synchronously printed.
Success and Failure in Pipeline GIS: Lessons Learned
Authors: Hlady Joseph T. , Buchanan Ken
Published: October 2008

In the geomatics community, the literature thoroughly covers the topic of success and failure in geomatics projects. Papers and research covering this topic as it relates to specific industries or applications such as municipal and environmental Geographic Information System (GIS) projects can also be found. However, few papers have been presented on this topic in relation to pipeline engineering projects, and in particular, Engineering, Procurement and Construction Management (EPCM). This paper will introduce this topic to the EPCM project manager through an overview of the measures of failure, their causes, the key enablers of success of a GIS project in EPCM world, and conclude with a synopsis of how the EPCM project manager can ensure the success of geomatics or GIS activities on their project.
Ductile Fracture Resistance Measurements in High Grade Steels
Authors: Pussegoda L. N. , Fredj A. , Fonzo A. , Demofonti G. , Mannucci G. , Rothwell B.
Published: October 2008

Recent developments in ductile fracture resistance measures in high grade steels in the pipeline industry include the crack tip opening angle (CTOA) and “steady state” fracture propagation energy, using 3-point bend specimens. The CTOA has been found to be a function of specimen ligament size. With the availability of instrumented hammers, it became possible to resolve propagation energy using the load-displacement curve using a single specimen. This paper focuses on refining the steady state fracture propagation energy, using back-slotted Drop Weight Tear Test (DWTT) specimens. The study included numerical simulation of the dynamic response of back-slotted specimens. The significance of the back-slot in altering the stress/strain field ahead of the propagation crack is discussed. The numerical simulation was also used to determine the strain rate in the “process zone” of the crack tip during steady state fracture propagation.
A New Adaptive Penalty Method for Constrained Genetic Algorithm and Its Application to Water Distribution Systems
Authors: Djebedjian Berge , Yaseen Ashraf , Rayan Magdy Abou
Published: October 2008

This paper presents a new adaptive penalty method for genetic algorithms (GA). External penalty functions have been used to convert a constrained optimization problem into an unconstrained problem for GA-based optimization. The success of the genetic algorithm application to the design of water distribution systems depends on the choice of the penalty function. The optimal design of water distribution systems is a constrained non-linear optimization problem. Constraints (for example, the minimum pressure requirements at the nodes) are generally handled within genetic algorithm optimization by introducing a penalty cost function. The optimal solution is found when the pressures at some nodes are close to the minimum required pressure. The goal of an adaptive penalty function is to change the value of the penalty draw-down coefficient during the search allowing exploration of infeasible regions to find optimal building blocks, while preserving the feasibility of the final solution. In this study, a new penalty coefficient strategy is assumed to increase with the total cost at each generation and inversely with the total number of nodes. The application of the computer program to case studies shows that it finds the least cost in a favorable number of function evaluations if not less than that in previous studies and it is computationally much faster when compared with other studies.
Design Concept and Production of High Deformability Linepipe
Authors: Ishikawa Nobuyuki , Okatsu Mitsuhiro , Endo Shigeru , Kondo Joe
Published: October 2008

Extensive studies to develop high deformability linepipe have been conducted. In the case of linepipes laid in seismic region or permafrost field, higher resistance to buckling against large strain induced by ground movement is required. In order to improve the deformability of pipes, two different types of microstructural control technologies were proposed, based on theoretical and analytical studies on the effect of microstructural characteristics on stress-strain behavior. Grade X65 to X100 linepipes with ferrite-bainite microstructure were manufactured by optimizing the microstructural characteristics. Grade X80 linepipe with bainitic microstructure containing dispersed fine MA constituents was also developed by applying new conceptual TMCP process. Deformability of developed linepipes with two different types of microstructure was evaluated by axial compression and bending tests, and all the developed linepipes showed superior resistance to buckling comparing with conventional pipes. Plate manufacturing technologies for producing recent high strength linepipe steel and the concept for microstructure control for improving deformability were also introduced in this paper.
Probabilistic-Based Assessment of Corroded Pipelines: A Comparison Between Closed Form and Surrogate Limit States
Authors: Hassanien Sherif S. Abdelatif , Adeeb Samer
Published: October 2008

Protecting steel pipeline systems from failure due to corrosions defects is a crucial issue in pipeline industry. Reliability models that use the rate of corrosion growth combined with closed form solutions for the failure pressure are often used to estimate the time periods before excavation and repair. A methodology is presented for the assessment of predicted failure pressure based on finite element analysis (FEA) and reliability analysis. Deterministic failure equations are transformed to probabilistic limit state models. The failure mode is considered to be controlled by the stresses due to internal pressure and the presence of corrosion. A response surface method (RSM) is utilized to build a surrogate model of the limit state function. A comparison between closed-form and the surrogate model approach is discussed. A stochastic model is assumed to match the uncertainty inherent in both loads and strength. Simulation-based approaches and asymptotic methods for probability of failure evaluation are used, namely, Monte Carlo simulation, importance sampling, First Order Reliability Method (FORM) and Second Order Reliability Method (SORM). An adaptive building of the numerical experimental design for the surrogate limit state is proposed. A new artificial neural network (ANN) is developed in order to reduce the computational cost of experimental design scheme’s evaluation. The outcomes obtained from such an approach are useful as a decision-making tool for the maintenance, repair or optimization of pipelines systems.
The Role of Continuous Cooling Transformation Diagrams in Material Design for High Strength Oil and Gas Transmission Pipeline Steels
Authors: Stalheim Douglas G. , Muralidharan Govindarajan
Published: October 2008

The economical, environmental, and safe movement of gas and oil to the marketplace requires transmission pipelines to be designed to operate at higher pressures and/or with improved toughness over a variety of temperature ranges. To meet the higher strength and toughness specification requirements of these transmission pipelines, appropriate materials and processes must be used in their design and construction. This includes selection of appropriate alloy composition, processing routes, microstructure control, and cost. A continuous cooling transformation (CCT) diagram is a tool that can be used to select alloy composition and processing route in order to obtain a specific, desirable microstructure for transmission linepipe steels in a cost-effective manner. In the past, CCT diagrams were developed experimentally under laboratory conditions, thus requiring extensive time and effort. However, with the vast data available and improved computational tools, reasonably accurate computer generated CCT diagrams can be produced quickly. These computer generated diagrams can give the materials design engineer a reasonable understanding of the effect of subjecting a given alloy to various processing routes and hence the resultant microstructures. Since final microstructure is a key variable in determining the linepipe steel material properties, the chosen alloy/processing route and its effect on the final microstructure needs to be understood. This paper will discuss the role of CCT diagrams in the design of steels (cost, alloy, processing, and microstructure) for oil and gas transmission pipelines. Examples of computer generated CCT digrams for various API alloy designs are included.
Oil-Gas-Water Three-Phase Slug Flow Liquid Holdup Model in Horizontal Pipeline
Authors: Zhao Jing Mei , Gong Jing , Yu Da
Published: October 2008

According to experiments and relational documents, slug regime, appeared in this experiment, can be divided into the following flow regimes: oil-based separated slug, oil-based dispersed slug, water-based separated and water-based dispersed slug. Experiments for oil-gas-water three-phase flow in a stainless steel pipe loop (25.7mm inner diameter, 52m long) are conducted. Compressed air, mineral oil and water are used as experiment medium. Mineral oil Viscosity is 64.5mPa.s at 20°C. Gas superficial velocity, liquid superficial velocity and water cut ranges are 0.5∼15 m/s, 0.05∼0.5 m/s and 0∼100% respectively. There are some strange observed in this experiment. At the very low gas superficial velocity less than 1m/s, the average liquid holdup of low liquid superficial velocity was larger than that of higher liquid superficial velocity especially in higher inlet water cut experiments. This is because at very low gas superficial velocity, the regime is separated slug flow which has water film below their liquid film zone, velocity difference between oil film and water film will affect the average liquid holdup greatly. With the increase of gas and liquid superficial velocity, the regime becomes dispersed slug flow which oil and water are homogeneous. It will be more obvious with the increasing of water cut for the thicker water film. A new liquid holdup model of oil-based and water-based separated slug has been developed. Based on statistical analysis, it is observed that the new model gives excellent results against the experimental data.
Assessment of Pipeline Safety Increase When Using Special Means
Authors: Timashev Sviatoslav A. , Yurchuk Zhanna V.
Published: October 2008

The paper describes an algorithm for assessing pipeline systems (PLS) safety increase due to implementation of special means. The algorithm is based on structural reliability and Boolean variables theory and is a step-by-step calculation of safety increase for a potentially dangerous object (PDO) due to implementation of the i-th safety means. An example is given of assessing pipeline operational safety change as related to third party intervention (TPI) when using different safety measures.
Long-Range Pipeline Monitoring by Distributed Fiber Optic Sensing
Authors: Inaudi Daniele , Glisic Branko
Published: October 2008

Distributed fiber optic sensing presents unique features that have no match in conventional sensing techniques. The ability to measure temperatures and strain at thousands of points along a single fiber is particularly interesting for the monitoring of elongated structures such as pipelines, flow lines, oil wells and coiled tubing. Sensing systems based on Brillouin and Raman scattering are used for example to detect pipeline leakages, verify pipeline operational parameters, prevent failure of pipelines installed in landslide areas, optimize oil production from wells and detect hot-spots in high-power cables. Recent developments in distributed fiber sensing technology allow the monitoring of 60 km of pipeline from a single instrument and of up to 300 km with the use of optical amplifiers. New application opportunities have demonstrated that the design and production of sensing cables is a critical element for the success of any distributed sensing instrumentation project. Although some telecommunication cables can be effectively used for sensing ordinary temperatures, monitoring high and low temperatures or distributed strain present unique challenges that require specific cable designs. This contribution presents advances in long-range distributed sensing and in novel sensing cable designs for distributed temperature and strain sensing. The paper also reports a number of significant field application examples of this technology, including leakage detection on brine and gas pipelines, strain monitoring on gas pipelines and combined strain and temperature monitoring on composite flow lines and composite coiled-tubing pipes.
Burst Strength of Gouges in Low Toughness High Pressure Transmission Pipes
Authors: Leveque Emeline , Zarea Mure`s , Batisse Remi , Roovers Paul
Published: October 2008

The “State-of-the-art review of the existing fitness-for-purpose assessment methods for damaged pipelines” [1] performed recently by Advantica identified, among others, the need to set a limit for the use of failure criteria for gouges and corrosion defects in the toughness-independent regime. This issue has very practical implications, as the length of older pipelines currently operated and having toughness values potentially leading to toughness-dependent failure behavior is not negligible. EPRG launched a project aimed at establishing a limit on the toughness value that separates toughness-dependent from toughness-independent burst failure behavior of gouges. The mainly experimental work checks the toughness related behavior of gouges on varying diameters of gas transmission pipes; small diameter (150 mm), medium diameter (350 mm), and large diameter (900 mm). Pipe material is carefully characterized in terms of tensile properties, Charpy energy, and shear area. Then, based on the toughness independent criterion, a set of gouges is defined, of different depths / lengths, so as to span the different regions of the criterion, covering both short and long defects. These defects are manufactured by spark erosion, resulting in thin slits. Each such slit is incorporated into a vessel that is submitted to a burst test, with a number of additional measurements, like strain gauges on the pipe surface, a clip gauge at the center of the defect, etc. The results are interpreted both in terms of comparison with the available assessment criteria, and also in terms of analysis of the failure surface, to identify failure mechanisms. A new interpretation in terms of constraint is proposed in order to explain some a priori unexpected experimental results.
Crack Propagation Modeling and Crack Arrestor Design for X120
Authors: Fonzo Andrea , Meleddu Andrea , Di Biagio Massimo , Mannucci Gianluca , Demofonti Giuseppe , Petersen Clifford W. , Biery Nicholas E.
Published: October 2008

The new, higher grade pipeline steels provide an opportunity to reduce pipeline costs by enabling a shift to higher pressure at reasonable wall thickness. However, these higher operating stresses place greater demands on the pipeline, particularly when a running fracture is considered. Several studies have shown that intrinsic arrest cannot be counted on for these grades under all operating conditions. In such cases, crack arrestors will be needed. This paper presents results obtained using CSM’s proprietary PICPRO® finite element code to predict the performance of crack arresters on X120 pipes, and shows that the predictions agree well with full-scale experimental results obtained in arrestor trials.
When Old Line Pipes Initiates Fracture in a Ductile Manner
Authors: Wilkowski G. , Rudland D. , Rider D. , Mincer P. , Sloterdijk W.
Published: October 2008

This paper presents a procedure to determine the lowest temperature that a ductile fracture will initiate in old (or new) pipe that behaves in a brittle manner (by Charpy testing). Over the last decade, much work has been done to assess constraint effects on the crack-driving force for specimens and cracks in pipes. The material’s transition temperature where the fracture process changes from ductile tearing to cleavage fracture at crack initiation is affected by the constraint conditions, but is a material property that cannot be determined analytically. This paper presents a methodology to account for constraint effects to predict the lowest temperature where ductile fracture initiation occurs and relates that temperature back to Charpy impact data for X60 and lower grades, particularly for older vintage linepipe materials. The method involves a series of transition temperature shifts to account for thickness effects, strain-rate effects, and constraint effects to give a master curve of transition temperatures from Charpy data to through-wall-cracked or surface-cracked pipes (with various surface-crack depth values) under quasi-static loading. These transition temperature shifts were based on hundreds of pipe tests and thousands of specimen tests over several decades of work by numerous investigators. Conducting tests on 1927 and 1948 vintage line-pipe steels subsequently validated this method. In addition, data were developed on the 1927 vintage pipe material to assess the effect of the bluntness of a corrosion flaw on the lowest temperature where ductile fracture will still occur under quasi-static loading. An addition transition temperature shift occurs as a function of the bluntness of the flaw.