bluuebunny/crossref_metadata_2025 huggingface dataset:
The Effect of Weld Metal Manganese Content on the Microstructure, Mechanical Properties and Hot Crack Susceptibility of Helically Welded Linepipes
Authors: Pourkia Navid , Marashi Pirooz , Leylabi Rouzbeh , Tabatabaei Seyed Alireza , Torshizi Hadi
Published: July 2009

The effect of manganese addition on decreasing hot crack susceptibility of submerged arc welding in microalloyed steels is well understood, but its increment should not cause unsuitable changes in metallurgical and mechanical properties of weld metal. Therefore, since weld metal Mn content in SAW process is mainly controlled by welding wire composition, the aim of this investigation is to study the effect of wire Mn content on the microstructure, mechanical properties and hot crack susceptibility of helical linepipes weld metal. In this regard, three different wires with 0.88, 1.05 and 1.54 wt% of Mn content were selected and welding was performed in both experimental and production process condition of X70 helical linepipes. As a result, 1.26, 1.44 and 1.67 wt% of Mn in weld metal was obtained respectively. Metallographical examinations using optical and scanning electron microscopy showed that, increasing the amount of Mn in weld metal, decrease the grain size of all phases (acicular ferrite, primary ferrite and ferrite with aligned second phase). Moreover, in the expense of increasing acicular ferrite, the volume fraction of primary ferrite (mostly grain boundary ferrite) and ferrite with aligned second phase decreased. Also, the results of mechanical properties indicated that the higher the amount of Mn, the higher the strength and hardness of weld metal, but in the case of impact toughness and tensile elongation, an optimum level was observed and lower toughness in the highest Mn content weld metal is attributed to the increasing hardenability and thus formation of martensite/retained austenite islands and grain boundary carbides in coincident sites of acicular ferrite grains. Moreover, analyzes in more than 1000m helical linepipes weld metal length showed that increasing weld metal Mn content up to 1.4wt%, reduced the possibility of hot crack formation from total percentage of 0.005 to around 0.001.
Burst Tests for High-Pressure Hydrogen Gas Line Pipes
Authors: Aihara Shuji , O̸stby Erling , Lange Hans I. , Misawa Kei , Imai Yasuhito , Thaulow Christian
Published: July 2009

Burst tests of line pipes containing high-pressure hydrogen and methane gas were conducted. The pipes tested were X65 ERW pipes with 267mm outer diameter and 6mm wall thickness. Applied pressures were 12 and 15MPa. A 300mm long crack was initiated by a shaped charge. Unstable shear fracture propagated at velocity of approximately 200m/s and then arrested. It was demonstrated that the arrested crack lengths were shorter in the hydrogen gas burst tests than methane gas burst tests. Pressure measurement indicated that decompression wave in hydrogen gas propagated faster than that in methane gas. This is the primary reason to the shorter arrested crack lengths for the hydrogen gas burst tests. The test results are discussed based on numerical analyses of gas decompression behaviors.
Study of Feature Extraction Method in Ultrasonic Phased Array Testing for Long-Distance Pipeline
Authors: Li Jian , Zhan Xianglin , Chen Shili , Zeng Zhoumo , Jin Shijiu , Wang Likun , Chen Pengchao
Published: July 2009

Though ultrasonic phased array technology is more efficient than traditional manual ultrasonic testing method, automatic flaw classification is a challenge and still hasn’t been well solved. Whether the representative features can be extracted from each type of ultrasonic flaw signal is a key to influencing the accuracy rate of automatic flaw classification. In this paper, second generation wavelet transform (SGWT) is proposed as a flaw feature extraction method, having the advantages of high computation speed, simple structure and occupying less memory. After introducing the principle of SGWT, the SGWT-based feature extraction algorithm is analyzed. Separability measure based on Euclidean distance is introduced as the evaluation criterion to assess flaw feature extraction performance. For comparison, first generation wavelet packet transform (WPT), a common feature extraction method, is also adopted to extract flaw feature. The experiment result is indicated that the classification performance of SGWT-based feature extraction algorithm is improved than WPT-based feature extraction algorithm, and the classification speed of the former is almost two times of the latter, which is valuable for automatic flaw detection and classification of pipeline girth weld.
Study on Dissimilar Metal Welding Between SAF2205 and X65 Pipes
Authors: Wang Xiaoyan , Zhang Lei , Wang Yalong , Lu Minxu
Published: July 2009

Kela-2 Gas Field is the main supply for the West-East Gas Pipeline which runs across China with length of 4000 kilometers. Natural gas from Kela-2 contains CO2/H2S sour components and 10% condensation water, which makes the medium present very strong corrosivity. In avoidance of corrosion failure, DSS SAF2205 line pipes were introduced to transmit the gas from the Gas Field to gathering center and processing factory. The DSS pipeline is totally about 13km and it is the first time DSS pipes were used largely amount in oil and gas pipeline around the world. As it is known, DSS SAF2205 pipes and traditional linepipes X65 were welded together between the gathering lines and mainline. Properties of welding joints, especially corrosion resistance, are very important for the safety of the pipeline. In this paper, the dissimilar metal joints were welded by Metal Inertia Gas Welding (MIG) with ER2209 electrodes to study and optimize welding procedure. Optical microscope, scanning electronic microscope and energy dispersive spectrometer (EDS) were employed to observe microstructure and analysis alloy elements distribution in the jointing zone between the dissimilar steels. Along the dissimilar joint, the microstructure changes from duplex characteristic combination of Ferrite and Austenite to that with Ferrite and a few Pearlite or MA. Smooth and notch tensile test and low temperature impact tests were also used to investigate mechanical properties of the dissimilar joints. Corrosion resistance of dissimilar metal joints were tested and analyzed. Weld metal produced with ER2209 presents excellent resistance to general corrosion in 1M NaCl solution. It is found that the ER2209 electrode is more suitable for producing the dissimilar weld joint according to this job.
Development of a Self-Propelled Surface Corrosion Inspection System for Medium Pressure Welded Steel Pipe
Authors: Adachi Toshiaki , Unishi Hiroyuki
Published: July 2009

It is important to perform corrosion inspections on pipelines. The magnetic flux leakage (MFL) pig inspection system is applied to high pressure pipelines, but this system cannot be applied to medium pressure (under 1MPa) gas pipelines. To resolve the above problem, we have developed the Self-propelled Corrosion Inspection System for Unpiggable Gas Pipeline. The self-propelled inspection system can measure the pipe wall thickness with dry coupling ultrasonic sensors. The system consists of front/rear tractor, sensor unit, ultrasonic thickness measurement device, water supply unit, control unit, cable and monitor. In this system, the sensors (ultrasonic type) have particularly unique characteristics. (1) Adopting the ultrasonic pulse method achieves measurement precision superior to the MFL method. (2) The sensor unit is equipped with six tire type (dry coupling type) ultrasonic sensors that can perform wall thickness measurement at a rate of 3m/minute and at 5mm mesh. The following benefits are obtained by adopting the system. (1) Expanding the inspection range: The system can directly inspect corrosion of pipelines at locations where excavation is difficult or where a pipeline passes through a bridge, though the pipelines could not be inspected formerly. (2) Improving measurement performance: The self-propelled system with ultrasonic thickness sensors runs in the pipe and the wall thickness is measured automatically at all the positions of the pipe. This report describes the inspection system development process and the results of trial inspections.
Study on Natural Gas Drag Reduction Agent and Mechanism of Gas Pipelines Drag Reduction
Authors: Li Guoping , Zhang Zhiheng , Liu Bing , Li Chunman , Chang Weichun , Bao Xuchen
Published: July 2009

On the basis of the study on the principle of oil flow and that on mechanism of drag reduction and transportation promotion of oil pipelines, the article makes a further research on the Mechanism of Drag Reduction in the gas pipelines. It points out that the basic cause for gas pipelines drag reduction is to control effectively the radial pulsation of gas adjacent to pipeline wall. It is considered that the most effective drag reduction method is to reduce the pipeline wall’s roughness degree and pipeline wall’s undercoat and to make gas drag reduction agent adjacent to pipeline wall. The research shows that gas drag reduction agent should be a polymer and compound with polarity and nonpolarity long chain.
Preliminary Environmental Assessment for the Site Selection for the UTGCA (Gas Treatment Unit for Caraguatatuba - SP)
Authors: Secron Marcelo Bernardes , Hurtado Shanty Navarro , dos Santos Medeiros Daniella , de Oliveira Wilson Jose´
Published: July 2009

The Preliminary Environmental Assessment (PEA) at Petrobras consists, in general terms, of an internal technical process, prior to environmental permitting, to verify the environmental feasibility of a project and identify the main environmental issues. It will also add to the future Environmental Impact Assessment Study (EIA). The technical guidelines for the PEA are prepared by the multidisciplinary team at the Petrobras Environmental Assessment Engineering Group (EAMB) of ENGENHARIA/IETEG/ETEG and are based on the characteristics of the project. The PEA is one of the elements of the environmental impact assessment, providing an initial assessment of the environmental aspects of the project (Screening). It also supports the assessment and determination of route and location alternatives of pipelines and industrial plants. The UTGCA (Caraguatatuba Gas Treatment Unit) will process gas and condensate from the Mexilha˜o Field, on Santos Basin – SP. This paper presents the procedures and conclusions of the PEA prepared for the UTGCA project by PETROBRAS/ENGENHARIA/IETEG/ETEG/EAMB.
Investigating the Effects of Mining Subsidence on Buried Pipeline Using Finite Element Modeling
Authors: Wang Xiaolin , Shuai Jian , Ye Yuanxi , Zuo Shangzhi
Published: July 2009

To investigate the effects of mining subsidence on buried pipeline, a computer program to predict three-dimensional ground movement is developed based on Probability Function Integration Method and pressurized pipeline subject to ground subsidence is modeled by using finite element method. Pipeline deformation, stress, strain and the influence of pipeline route are analyzed. The results show that bending combined with compression and twisting results in high stress and strain level for pipeline running athwart subsidence area, while for pipeline parallel to strike or oblique direction of mining gob, obvious twisting is not found and main deformation of pipeline is bending combined with tension which results in lower stress and strain than the former. It is recommended for pipeline design or route selection in mining area that pipeline should be laid parallel to the strike or oblique direction of mining gob in order to avoid complicated deformation.
Prediction of Failure Pressure of Corroded Pipelines Based on Finite Element Analysis
Authors: Shuai Jian , Zhang Chun’e , Chen Fulai , He Renyang
Published: July 2009

A numerical model for predicting the burst failure of corroded pipeline is constructed using the non-linear finite element method, in which the technical points including element mesh, materials model, non-linear solution and failure criterion are recommended. Using this model, the full-size pipe burst experiments in different material, size and defect was analyzed and computed. The proposed FEM model was validated. Based on the calculation result using the model, a new formula predicting failure pressure is proposed, in which depth, length and width of a defect was involved. Comparison of the formula with the other assessment method and experiments show the formula had a satisfactory precision.
Managing the Risk of Vibration Related Failures on Facility Pipework
Authors: Miles Toby , Andrews Bob
Published: July 2009

Vibration related fatigue accounts for a significant proportion of all pipework failures in process plant and pipeline facilities. Small bore pipework is particularly at risk and example failures are presented which highlight these concerns. Operators of large diverse assets, such as a gas processing plant, or a large asset base, such as a series of compressor stations, may have some difficulty in identifying plant, pipework and fittings at risk. An approach to address pipework vibration issues is therefore proposed to address this issue on facility pipework and assess the relative risk for prioritization purposes. A case-study is presented of a recent project that employed a multi-stage review process of a large number of different installations. This allowed resources to be concentrated on detailed investigation and development of solutions for the highest risk locations.
Modern High Strength Steels for Oil and Gas Transmission Pipelines
Authors: Siciliano Fulvio , Stalheim Douglas G. , Gray J. Malcolm
Published: July 2009

Increasing world demand for energy has resulted in plans to expand the oil and gas transmission pipeline infrastructure in many countries utilizing higher strength steels of API grade X70 and X80. Traditional transmission pipeline steels, up to grade X70, relied on a ferrite/pearlite microstructural design generated through traditional TMCP rolling of a niobium microalloyed C-Mn steel design. Increasing strengths up to X70 and X80 for transmission pipelines has resulted in a shift toward a ferrite/acicular ferrite microstructure designs. Traditionally, to generate the ferrite/acicular ferrite microstructure design for X70 or X80, TMCP rolling is applied to a C-Mn-Si-Mo-Nb alloy system. The Nb content is typically less than 0.070% in this alloy system. With the rising cost of alloys over the past three years, steel and pipe producers have been working with different alloy designs to reduce total costs to produce the ferrite/acicular ferrite microstructure. In recent developments it has been determined that an optimized low-C-Mn-Si-Cr-Nb alloy design (usually referred as NbCr steel), utilizing an Nb content between 0.080 – 0.11% can produce the same ferrite/acicular ferrite microstructure with either no, or minimal, use of molybdenum. This approach has been successfully used in several transmission pipeline projects such as the Cantarell, Cheyenne Plains and Rockies Express. Recognizing the success of previous projects around the world, the large ∼ 4500 Km 2nd West-East Pipeline Project specification in China has been modified to allow for the use of this NbCr design for both plate and coil for conversion to long seam or spiral pipe. The NbCr design allows the steel producer to utilize niobium’s unique ability to retard recrystallization at higher than normal TMCP rolling temperatures, hence the term for the alloy design High Temperature Processing (HTP), producing the desired ferrite/acicular ferrite microstructure with excellent strength, toughness and weldability. This paper will discuss the technical background, rolling strategy, mechanical properties, welding, specific projects, and specification modifications with practical examples.
Remote Monitoring of Pitting Corrosion Using a Next Generation Electric Field Mapping (EFM) System
Authors: Kubian Eric , Vorozcovs Andrew , Cauchi Sam
Published: July 2009

Pitting corrosion is one of the most serious problems in sour gas / oil pipelines and in crude oil refineries. Unlike generalized wall loss, pitting corrosion can grow at non-uniform rates and can rapidly proceed to full depth penetration. Such a loss of integrity can lead to leaks that cause production shutdowns, environmental damage, or in the worst case, loss of life. In practice, pitting corrosion is generally detected during pipeline inline inspection or during routine ultrasound scans undertaken as part of a maintenance program. Locations identified to exhibit pitting corrosion are then often risk ranked, and then either repaired or monitored depending on a variety of factors. Unfortunately, the sites where this type of corrosion frequently occurs are often inaccessible for frequent follow-up wall thickness inspections due to geographical remoteness or the need to the use of scaffolding to reach the site. This difficulty creates a need for an advanced internal corrosion monitoring system capable of remotely monitoring the progression of pitting corrosion. This paper describes a new pitting corrosion monitoring system based on the principal of Electric Field Mapping (EFM) and proceeds to describe recent results from an operational field installation of this technology. Using this technique, remaining wall thickness is carefully mapped out within a pre-defined area of interest. The system indicates the presence of any generalized corrosion in addition to the location, width, and depth of individual pitting corrosion defects. Innovations of this new EFM system include the use of a robust pre-fabricated fiberglass shell that significantly reduces the installation time compared to earlier technologies; non-welded contacts that have minimal metallurgical impact; permanent, self-powered on-site data acquisition system equipped with cellular or satellite data communication. Design principles of this technique are discussed, and installation procedures are outlined. Results are presented from a field site where pitting corrosion is being monitored on an ongoing basis. Background information on the installation, in addition to project goals and observations are reported. Daily wall thickness data obtained remotely from the site is used to report individual corrosion rates for pitting defects within the pipeline. These corrosion rates are then plotted over time and correlated to events such as process upsets, chemical inhibitor application, cleaning pig runs, and other actions intended to mitigate for internal corrosion. This correlation provides data which is then subsequently used to improve the corrosion mitigation program in place, and better schedule maintenance activities.
Towards a New Limit State Function for Determining the Failure Pressure of a Pipeline Containing Mechanical Damage
Authors: Jandu Chas , Francini Bob , Taylor Mike , Francis Andrew
Published: July 2009

Mechanical damage is generally considered to be damage that occurs to a pipeline when mechanical excavation, drilling, or boring equipment impinges on a buried pipeline creating scrapes, abrasions, gouges, punctures, and/or dents in the pipeline. Above ground pipelines may also be damaged in a similar manner from impacts by vehicles or projectiles or by willful acts of vandalism. In some cases, immediate failure will occur resulting in potentially catastrophic consequences. It is thus important to understand the conditions that would lead to such a failure in order to ensure that design parameters are selected such that immediate failures occur very rarely. In cases where the damage does not create an immediate failure or the release of gas, the concern generally is that a delayed failure will occur because the integrity of the pipeline has been significantly compromised. In such cases, the possibility is that repeated pressure fluctuations, small increases in pressure, or time-dependent creep will erode whatever margin of safety remains and a failure will ensue. Particularly unsettling are the cases in which damage of this nature is encountered through some form of inspection where the source of the damage and its time of creation are unknown. In such cases, the operator of the pipeline will generally not know what margin of safety remains. There are a number of models in existence that may be used to predict both instantaneous and delayed failures due to mechanical damage and indeed these have been used quite extensively as the basis of repair criteria and for determining safe pipeline operating conditions. Nonetheless, there are significant elements of uncertainty associated with these models and for this reason an adequate reserve factor needs to be incorporated or recourse must be made to probabilistic approaches that address such uncertainty. However, since pipelines are getting older and in some cases are being operated at higher pressures than they were previously, there is a requirement to obtain a better understanding of the significance of mechanical damage. In view of this Pipelines Research Council International (PRCI) and other research bodies, such as European Pipelines Research Group (EPRG), are taking a keen interest in this topic. To this end, PRCI have commissioned an extensive research program to investigate all key aspects of both instantaneous and delayed failures. Kiefner and Associates Incorporated (KAI) and Andrew Francis and Associated Ltd (AFAA) were commissioned to investigate the conditions that cause instantaneous failures. The purpose of this paper is to describe the approach that was adopted and the formulation of the new model that emerged from study. This model is being validated through testing which is currently ongoing.
Best Practices in Damage Prevention for Parallel Construction Projects
Authors: Byrd W. R.
Published: July 2009

New pipelines are increasingly being encouraged (or forced...) to share common or adjacent rights of way with existing utilities. Installation parallel to existing underground facilities for long distances greatly complicates construction and damage prevention, and creates a multitude of opportunities for damage to occur. This paper describes current regulatory and industry association efforts to address these issues, and gives a case study of a real accident that was caused during parallel construction of a water main adjacent to an HVL pipeline.
A Pipeline Integrity Assessment Software for Transmission Pipelines: Gadline®
Authors: Poignant Magali , Lesueur Virginie , Pognonec Gae¨l
Published: July 2009

Despite all attention given to natural gas transmission pipelines, defects due to corrosion and third party activities can still be detected. These defects should be assessed and pipeline repair or replacement may be required. Gaz de France R&D Division has developed a methodology and an associated software to assess the integrity of ageing operating pipelines and to build inspection and re-inspection program: “GADline®”. The “GADline®” methodology and associated software allows: - to assess defects with deterministic and probabilistic methods. Six defect types are taken into account in the software: corrosions, gouges, grinding metal losses, dents, gouges in dents, and dents associated with grinding metal losses. For each of these defects, burst and fatigue behaviors are assessed, based on well-known criteria (BS7910, B31G and EPRG) and criteria developed by Gaz De France. All these criteria have been validated throughout tests campaigns to suit the actual behavior of the defects detected on the Gaz de France pipeline network. - to classify the defects in three categories: acceptable, temporarily acceptable or unacceptable. Thanks to the software, the acceptability results can be easily read on a defect assessment diagram and result sheets can be printed. - to analyze defects detected by in-line inspection or above ground surveys. Defect dimensions measured by pigs or after manual measurements can be used as input data, allowing more or less accurate analysis. - to prepare intervention programs. These intervention programs allow to identify the locations, where a drop in pressure is necessary to preserve the integrity of pipeline and the safety of people and environment. They also allow to identify locations, where future interventions will be necessary. Finally they facilitate the decision making process regarding re-inspection program frequency by calculating failure probability per km for each corrosion defect. (This module software is detailed in another IPC article. [1])
Blasting and Construction Vibrations Near Existing Pipelines: What Are Appropriate Levels?
Authors: Francini Robert B. , Baltz William Nik
Published: July 2009

Construction and industrial processes such as mining and quarry blasting or pile driving near a pipeline create vibrations that will result in stress on the pipeline. This stress is added to the normal operating stress on the line. The obvious way to determine these stresses is by exposing the pipeline, installing strain gauges, reburying the line and measures its response to the event. This is very costly and not a practical approach in most cases. A common method that is used for monitoring these activities is to measure the vibration of the ground above the pipeline. The question then becomes, how do these vibrations relate to the stress on the pipe? The answer to this question is very important both to the pipeline and the construction/process operators as it will determine what the allowable vibration levels are. We will present the results of a recent project where 4 pipelines located within a coal field production area were instrumented with strain gauges and the stress on the lines measured along with the particle velocity in the soil above the lines during a large blast. This data will be compared with blasting data generated by the Bureau of Mines and Esparza. We will then look at methods for estimating the stress to see how they compare with the data. Finally we will present guidelines for determining acceptable vibration levels over a pipeline based on these results and an integrity analysis of the pipeline.
Reduction Factors for Estimating the Probability of Failure of Mechanical Damage Due to External Interference
Authors: Cosham Andrew , Haswell Jane , Jackson Neil
Published: July 2009

Quantified risk assessments (QRAs) are widely used in the UK to assess the significance of the risk posed by major accident hazard pipelines on the population and infrastructure in the vicinity of the pipeline. A QRA requires the calculation of the frequency of failures and the consequences of failures. One of the main causes of failures in onshore pipelines is mechanical damage due to external interference, such as a dent, a gouge, or a dent and gouge. In the published literature, two methods have been used to calculate the probability of failure due to external interference: • historical failure data and • limit state functions combined with historical data (i.e. structural reliability-based methods). Structural reliability-based methods are mathematically complicated, compared to using historical failure data, but have several advantages, e.g. extrapolation beyond the limited historical data, and the identification of trends that may not be apparent in the historical data. In view of this complexity, proposed supplements to the UK pipeline design codes IGE/TD/1 (natural gas) and PD 8010 (all substances) — on the application of QRAs to proposed developments in the vicinity of major accident hazard pipelines — include simple ‘reduction factors’ for use in ‘screening’ risk assessments. These ‘reduction factors’ are based on a comprehensive parametric study using a structural reliability-based model to calculate the probability of failure due to mechanical damage, defined as: gouges, and dents and gouges. The two ‘reduction factors’ are expressed in terms of the design factor and wall thickness of the pipeline. It is shown that, through appropriate normalisation, the effects of diameter, grade and toughness are secondary. Reasonably accurate, but conservative, estimates of the probability of failure can be obtained using these ‘reduction factors’. The proposed methodology is considerably simpler than a structural reliability-based analysis. The development and verification of these ‘reduction factors’ is described in this paper.
Dynamic Apparatus for CTOA Measurement in Pipeline Steels
Authors: Shtechman Avigdor , McCowan Christopher , Reuven Rony , Drexler Elizabeth , Darcis Philippe , Treinen J. Matthew , Smith Robert , Merritt James , Siewert Thomas , McColskey J. David
Published: July 2009

When a crack initiates and propagates in a pressurized pipe, the only thing that might stop this high-velocity event is the release of internal pressure (decompression), resulting in a deceleration in the crack-propagation rate. This deceleration can be achieved through the use of crack arrestors, or the ability of the pipeline material to resist ductile fracture. To evaluate the resistance to crack growth, the crack tip opening angle (CTOA) is used. Recent articles on the CTOA of pipeline steels at quasi-static rates with modified double cantilever beam specimens (MDCB), and at dynamic displacements rates by use of drop weight tear testing have provided data to support this need. These laboratory results from the literature, compared with results of full-scale tests, indicate that details of the fracture mode depend on the rate of fracture. To further study the dependence among the rate, fracture mode, and CTOA, a dynamic test apparatus was designed to perform CTOA testing of MDCB specimens, so that comparisons to quasi-static and full-scale results could be made. This new apparatus consists of a 500 kN uniaxial hydraulic test machine capable of stand-alone displacement rates of 300 mm/s, and a disc spring apparatus that is used to further accelerate the testing displacement rate. Initial results of the testing show that full slant fracture mode is observed at the highest rates tested for X65 and X100 steels. Maximum crack velocities approaching 10 m/s were recorded with highspeed photography. CTOA measurements were typically made at a position about 30 mm ahead of the pre-fatigue crack, over a distance of about 15 mm in the steady-state crack propagation regime. In this paper, we describe the high-speed apparatus, discuss the relationship among specimen configuration, crack speed, and CTOA, and present initial results on X65 and X100 pipeline steels.
Increasing the Application Realm of Solid Expandable Technology
Authors: Noel Greg , Waddell Kevin
Published: July 2009

Technology that boasts versatility is indicative of true innovation. Take for example solid expandable tubulars. Since 1999, upstream operators have successfully used solid expandable tubulars with over 900 installations worldwide. The success of these tubular systems to mitigate wellbore challenges and casing problems has prompted pipeline operators to consider the transfer of solid expandable technology to pipeline repairs and restorations. A key value proposition that initiated the pipeline industry’s attraction consists of the technology’s permanent, steel, pipe-in-pipe ability to improve structurally at-risk or derated pipelines with only minimal ID loss. Although local distribution companies have used liner technology extensively in settings where lines operate at much lower pressure than most transmission lines, the use of steel lining is new. The concept is simple: insert a smaller pipe inside a larger pipe and, using pressure, drive a specially designed mandrel through the smaller pipe to accomplish a controlled expansion to fill the annular space between the two. This less-intrusive process is a “trenchless” solution to replace and repair sections thinned by corrosion to maintain maximum throughput and reinforce pipelines against external loads to prevent buckling or collapse from soil movement and shifting formations. Such an approach enables pipeline restoration with minimum disruptions due to repairs—a significant benefit in heavily congested areas and geologically sensitive environments. Research indicates that prime candidate applications of solid expandable technology exist in situations where traditional excavate-and-repair techniques are difficult to use, cost prohibitive, or would disrupt public movement. In such settings, the two broad categories solid expandable technology would address most effectively are capacity restoration and anomaly repair. This paper will discuss conventional solid expandable tubular technology and the legacy it provided to transition to pipeline applications. Expansion value and application will be discussed in addition to lab and surface testing and development-to-date. In addition, this paper will propose the next steps needed to transition the technology to a viable pipeline rehabilitation method.
Improving the Integrity of Lap Joint Flange Connections
Authors: Grmek Damir
Published: July 2009

Bolted connections where proper alignment is critical usually require the use of lap joint flanges. The ability of lap joint flanges to swivel around the pipe enables the connection to be installed with no rotational stress applied to the attached piping and equipment. The majority of lap joint flanges on the Enbridge Pipelines system are ANSI 600 and are located at pump nozzles. In these applications, Enbridge Pipelines’ standard specifies the use of spiral wound gaskets with inner rings. Problems with lap joint flanges typically occur at the time of assembly. There are a number of factors that contribute to the challenges of properly seating a gasket in these joints: • Since the raised face is separate from the flange, there is some flex in the face that could unevenly load the gasket; • The flange may not be concentric with the raised face that is welded to the pipe because of clearance between the pipe OD and the flange ID. Using the bolt holes to align the flange does not necessarily ensure that the raised faces are aligned; • Line up pins are not recommended on pump nozzles in order to ensure that no stress is placed on the pump. Consequently, the bottom studs are used to center the gasket and it is possible for the gasket to sit in the stud threads, increasing the misalignment between the gasket windings and the flange raised faces; • Specified torque values for a given flange size may be too high for use in a lap joint application. The perfect bolt alignment in these joints may result in a lower nut factor and subsequently a higher bolt stress for a given torque value. All of these factors can cause damage to the windings on a spiral wound gasket, eventually resulting in a leak. This paper will discuss ways to mitigate these issues.
Automation Improvements in Batch Cutting Process: The Last Profit Center for Pipelines
Authors: Harbert Timothy R.
Published: July 2009

Two major developments have recently emerged driving pipeline companies to re-evaluate transmix and regrade generation within their systems, along with the process which is the primary driver of transmix production — batch cutting. Dramatic increases in product cost and the advent of ultra low sulfur (ULS) regulation and ULS products have brought renewed focus on transmix generation and control. Given that pipeline tariffs are generally controlled by government agencies, and power cost can only marginally be controlled, transmix/regrade reduction and the corresponding savings is probably the last great revenue generator for pipelines and shippers. Batch cutting techniques and technology have remained largely unchanged for several decades. However, new technologies and greater automation have created renewed opportunities to significantly reduce transmix/regrade on a system-wide basis. Analysis has shown that projects related to transmix reduction are highly profitable and improve the overall precision and accuracy of batch cutting. This paper reviews the sources of variability in the manual batch cut process and how this variability can be eliminated through automation and new technologies.
The Effects of Squarewave Polarity Parameters on Microalloyed Steel Charpy V-Notch Results
Authors: Pepin J. , Penniston C. , Henein H. , Ivey D. G. , Wiskel J. B. , Boyd J. D.
Published: July 2009

The welding processes used to produce microalloyed steel pipe can result in mechanical property changes in the heat affected zone (HAZ) regions of seam and double joint (circumferential) welds. HAZ properties are controlled primarily by the microstructures resulting from the thermal history during welding. While multi-pass welds have successfully achieved CVN values greater than 66.4 ft-lbs (90 J) at the fusion line, this work explores the use of single-OD welds to achieve similar toughness values. Thus, single OD-pass submerged arc welding (SAW) test specimens were produced to examine the effect of electrode polarity on the HAZ Charpy V-notch (CVN) toughness. CVN results indicate that a DC+ lead, AC 50% trail tandem arc setting produces moderately improved CVN test HAZ results at −20°C compared with an AC 75% lead, AC 25% trail tandem arc setting. The difference is believed to be related to differences in effective heat input, though further investigation is required. The CVN specimens notched furthest from the fusion line gave the largest toughness result scatter. The elevated values are believed to be the result of greater lengths of the notch passing through unaffected base metal. Lower values (average CVN from 37 to 59 ft lbs (51 to 80 J)) were produced by notches located at the fusion line, which would pass through significant amounts of coarse grain heat affected zone (CGHAZ). The weld and base metal CVN results for both sets of welding conditions were comparable. Further optimization of welding parameters is required for a single pass weld procedure to achieve HAZ CVN values exceeding 66.4 ft-lbs (90 J) at the fusion line.
Strain Aging Effects in High Strength Line Pipe Materials
Authors: Duan Da-Ming , Zhou Joe , Rothwell Brian , Horsley David , Pussegoda Nick
Published: July 2009

Strain aging behavior can occur in almost all steels, including micro-alloyed steels used in high-strength pipelines. The direct effects of strain aging on mechanical properties can include increased hardness, yield strength and tensile strength, and reduced ductility and toughness. Strain aging may take place in processes where the pipe material experiences thermal cycles, such as coating, welding and in-service heating, and may occur with or without additional plastic strain. The changes of material mechanical properties could seriously challenge the design principles and methodologies, so that these aging effects need to be taken into account. This is especially important for pipelines expected to see deformation-controlled loading conditions. This is not only because the difference in strain aging effects between a weld and the parent material can easily change the strength overmatch condition of the weld, leading to unpredictable girth weld flaw tolerance, but also because the return of Lu¨ders behavior on the stress-strain curves of these materials significantly reduces the pipe buckling load resistance. In addition, any change in fracture resistance due to strain aging may impact the fracture control design practice, particularly if the pipe material may be expected to experience plastic deformation during service. In this paper, a brief review of strain aging behavior in steels is presented, with an emphasis on the effects on the mechanical properties and toughness of three high-strength line pipe steels. Material strain aging mechanical test procedures of three high grade pipes will be described and the test results will be discussed.
Improving and Expanding Guided Wave Ultrasonics as an Assessment Option
Authors: Smith Robert W. , Barrett Zach
Published: July 2009

The Pipeline and Hazardous Materials Safety Administration (PHMSA), the pipeline industry and standards developing organizations (SDOs) are collaborating to improve the effectiveness and expand the application of Guided Wave Ultrasonics (GWUT). This paper will illustrate how these initiatives through integrity management (IM) regulation, collaborative research and development, technology demonstrations and consultation with subject matter experts (SME) are driving these improvements. These efforts are integrating GWUT technology with External Corrosion Direct Assessment (ECDA) and Pipeline Safety IM protocols and supporting higher confidence inspection of cased crossings. Previous to these initiatives only In-Line Inspection, Pressure Testing and Direct Assessment provided assessment options for the pipeline industry.
Mapping Stress Corrosion Cracks Using Eddy Current Array Sensors
Authors: Tomar Munendra S. , Fingerhut Martin , Hansen Ben
Published: July 2009

Rapid and reliable in-the-ditch characterizing and assessment of SCC on natural gas and hazardous liquids pipelines, identified through Integrity Assessment methods or through integrity rehabilitation and maintenance work, continues to be a challenge. Determining SCC severity and making reliable remaining pipe strength predictions requires as a minimum, crack length and crack depth be known. Detailed assessment of crack colonies also requires knowledge of the spacing and relationship of one crack to another. This paper describes the results of a Joint Industry Project (JIP) that comprised of a comparative study of the performance of the Eddy Current Array Sensors relative to the current industry standard of Magnetic Particle Inspection (MPI) for the detection of Stress Corrosion Cracks (SCC) in pipeline steel. The purpose of this study was to qualify the eddy current sensor as an applicable alternative to current practices, given the increasing need for quantifiable results and for analytical capabilities to assess SCC indications.
Crack Propagation and Arrest in X70 1420x21,6mm Pipes for New Generation of Gas Transportation System
Authors: Pumpyanskyi Dmitry A. , Lobanova Tatiana P. , Pyshmintsev Igor Y. , Arabey Andrey B. , Stolyarov Vladimir I. , Kharionovsky Vladimir V. , Struin Alexey O.
Published: July 2009

The ductile fracture arrest capability of gas pipelines is seen as one of the most important factors in the future acceptance of new high strength pipeline steels for high pressure applications. New North-European pipeline project is based on application of X70 pipes designed for high gas pressure of 9,8MPa. To study fracture propagation behavior in cold climate the full scale tests were carried out using longitudinally and spiral welded pipes with different microstructure of base metal. Results of the tests with crack propagation studies in predominately ferrite-pearlite (FP) and acicular ferrite (AF) steels possessing similar Charpy energy are presented. Crack propagation mechanisms in base metal and along spiral weld were studied and are presented with strain distribution along crack.
Stress Corrosion Crack Initiation in X-65 Pipeline Steel Under Disbonded Coating With Cathodic Protection
Authors: Fang Bingyan , Eslami Abdoulmajid , Kania Richard , Worthingham Robert , Been Jenny , Chen Weixing
Published: July 2009

A novel testing setup has been used in this study to simulate crack initiation in X65 pipeline steel exposed to near-neutral pH soil environment. This test setup was designed to simulate synergistic interactions of cathodic current with soil environments underneath the disbonded coating on the pipe surface. It was found from the simulations that the local environment underneath the disbonded coating can be very acidic or alkaline, instead of near-neutral pH as commonly believed, depending on seasonal fluctuation in CO2 level and cathodic current. There exists a wide range of corrosion conditions on the steel surface up the gradient of cathodic current underneath the disbonded coating. General corrosion was found to increase as CP current diminishes. Pitting corrosion in terms of number of pits and size of pits was found to be the most severe at locations where cathodic protection was nearly diminished. These locations had also developed some crack like-defects, which were usually elongated in a direction perpendicular to the loading axis and appeared to be formed from a linkage of neighboring pits and by enhanced corrosion at stress raisers.
Shell Corrosion Allowance for Aboveground Storage Tanks
Authors: Tetteh-Wayoe Debra
Published: July 2009

Enbridge Pipelines Inc. utilizes aboveground crude oil storage tanks for operational flexibility and merchant storage purposes. Most of these tanks are built in accordance with the requirements of API 650. This standard requires that an appropriate corrosion allowance be included in the minimum shell thickness calculations. A variety of sources were researched in an effort to develop a process that ensures the selected corrosion allowance allows for the safe operation of a tank for its entire service life. Some of these sources include other API standards, historical API 653 tank inspection reports, published atmospheric corrosion rates, and corrosion allowance specifications of industrial counterparts. Defining an appropriate corrosion allowance requires consideration of a number of factors: • Whether or not the product contains significant sediments and water; • Whether or not an internal lining will be applied in accordance with API 652; • The length of time to the first out-of-service inspection; • Whether or not the tank will be externally coated; • The temperature of the product stored; • The annual precipitation at the specified location; • The average chloride concentration in rainwater at the specified location. During the course of the corrosion allowance study, the issue of maximum allowable design stress was also considered. The allowable stress values specified in the standard for construction of new tanks (API 650) differs from the allowable stress values specified in the inspection standard for existing tanks (API 653). It has been suggested that the incremental difference between the minimum shell thicknesses calculated using API 650 instead of API 653 could be designated as corrosion allowance. This paper will describe the corrosion allowance calculations in detail as well as address the issue of maximum allowable design stress.
The Development and Challenges of Pipeline Failure Analysis in China
Authors: Chen Xinhua , Feng Qingshan , Shui Biyuan , Li Baoji , Hao Jianbin , Teng Yanping
Published: July 2009

According to the failure history and the results of failure analysis, the failure of oil & gas pipeline in China was mainly caused by incorrect operations, manufacturing defects, corrosion and third-party damage. Based on a case of failure analysis, such problems as how to develop a standard template of pipeline failure incident / accident report, how to set a guideline of pipeline failure analysis and further improve the failure database of pipeline were discussed. In addition, the relationship between the prediction/prevention technology and risk assessment was also analyzed. Finally, a brief description about how to carry out the research of pipeline failure prediction/prevention technology and promote its application in China, especially for large-diameter, high-pressure gas pipeline was presented.
Pipeline Batch Cut Optimization by Taking Into Account the Quality of the Products at the Tanks
Authors: Tepedino Alexandre Figueira , Baptista Renan Martins , Freitas Rachid Felipe Bastos , Carneiro de Araujo Jose´ Henrique
Published: July 2009

This paper presents a methodology for determining the optimal cut point in pipeline batch transfers. The methodology aims to ensure the quality of products and, when possible, to maximize the product with higher economic value. The quality of the products is specified based on their purities as well as on the trace of chemical elements in their composition. The proposed methodology requires the use of interface sensors capable to monitor physical properties which can be converted into concentration of the products in the mixture. Simulations carried out with ultra-sonic interface detectors in a diesel-gasoline batch are presented to illustrate the technique.