bluuebunny/crossref_metadata_2025 huggingface dataset:
Fracture Control for the Alliance Pipeline
Authors: Eiber Bob , Carlson Lorne , Leis Brian
Published: October 2016

This paper reviews the fracture control plan for the Alliance Pipeline, which is planned for operation in 2000. This natural-gas pipeline is 2627 km (1858 miles) long, running from British Columbia, Canada to Illinois, USA.

Interest in the fracture control for this pipeline results from its design, which is based on transporting a rich natural gas (up to 15% ethane, 3% propane) at a relatively high pressure 12,000 kPa (1740 psi). This break from traditional pressures and lean gases, which frequently are constrained by incremental expansion, is more efficient and more economical than previous natural gas pipelines. Use of higher pressures and rich gas requires adequate fracture control for the line pipe, fittings, and valves. This fracture control has been achieved for the Alliance Pipeline by specifying high-toughness steels, in terms of both fracture-initiation and fracture-propagation resistance for the line pipe, fittings and heavy wall components.

While beneficial from an economics viewpoint, the need for higher toughnesses raised concern over the validity of the fracture control plan, which was based on existing and new technology. The concern focused on fracture arrest using high toughness steels. The concern was associated with characterizing fracture arrest resistance using Charpy V-notch impact toughness, the most commonly used method to measure fracture arrest resistance. Developments were undertaken to address problems associated with the use of higher-toughness steel and these were validated with full-scale pipe burst tests to demonstrate the viability of the fracture control plan.

The solution involved extending existing methods to address much higher toughness steels, which provided a significantly improved correlation between fracture arrest predictions and experimental results. In the burst tests, data was collected to validate the Alliance design and also to extend the database of fracture arrest data to assist future pipelines. Data such as the pressure between the pipe and soil as the gas escapes from the pipe, the sound levels in the atmosphere, the movement and strains in the pipe ahead of the running fracture were instrumented in the test and the available results are presented.
Simulation of Dynamic Ductile Failure in Pipelines
Authors: Pokutylowicz Norman , Luton Michael J. , Petkovic Ruzica A. , Nemes Jim A. , Yue Steve
Published: October 2016

A finite-element method computer simulation was constructed in order to assist in determining what material properties affect the resistance to dynamic ductile failure in pipelines. Such failure is caused by stable axial tearing that involves a substantial amount of plastic deformation, and is driven by the kinetic energy of the expanding gas. Various semi-empirical relationships exist in the literature to predict the toughness required for resistance to the propagation of a dynamic ductile failure, but these tend to be ineffective when applied to higher strength grades of steel. The present finite-element model is composed of two main sub-models. The gas decompression algorithm is based on analytical expressions and calculates the gas pressure throughout the pipe as the ductile fracture propagates. The material-response algorithm determines the behaviour of the material under the changing loading conditions. It simulates the material response, including rate-dependent yield as well as anisotropy of yield and work hardening. The model is validated by using comparisons with published data from the literature.

This paper focuses on a description of the different components of the model and their interaction. In addition some observations from the various simulations are discussed.
Characterizing Dynamic Crack-Resistance of Pipelines Using Laboratory-Scale Practices
Authors: Leis Brian N.
Published: October 2016

The consequences of a dynamic fracture in a gas-transmission pipeline require that they be designed to avoid such incidents with great certainty. Because of the complexity of this fracture process, the only certain approach to determine fracture-arrest conditions involved full-scale experiments. As time passed empirically calibrated balance equations between the crack-driving conditions and the line-pipe steels crack-arrest capabilities were developed. Such models worked well until the introduction of high-toughness line pipe, for which to full-scale test predictions were non-conservative, and increasingly so as toughness increased. Problems with early CVN-based models led to development of alternative schemes.

This paper presents results of experiments done to evaluate plausible alternatives to the CVN practice, which rely on an impact test identical to or adapted from the drop-weight tear-test (DWTT). As this practice is comparable to that of the CVN practice save for using an up-scale specimen geometry, results are presented and contrasted for these test methods, for pipe grades from B to X70, and toughness from less than 10 J in excess of 300 J. Data are analyzed to reveal trends not typically reported for such testing. It is shown that there is no essential difference between data developed from the CVN and DWTT practices, provided the results are compared at similar levels of impact-machine excess-energy capacity. Further, it is shown that non-conservative predictions of full-scale test behavior for higher-toughness steels can be traced to using the early CVN-based models at toughness levels well outside the range of their empirical calibration.
Participative Risk Management in the Construction of Onshore Pipelines
Authors: Barboza Tania S. , Borges Carlos Alberto , Neto Aluisio S. Xavier
Published: October 2016

Accidents related to production, processing, storage and transportation of oil and its by-products have been studied extensively because of their social and environmental impacts. However, accidents relating to construction of oil facilities have been largely ignored by researches, perhaps because such accidents involve a smaller group of people and result in smaller-scale environmental impacts.

Pipeline construction projects are particularly unique. As opposed to construction of processing plants, pipeline construction covers a very long reach, often involving varying site conditions. Consequently, there are more environmental issues, many of which vary from place to place along the pipeline route as a result of the differing soil, drainage, vegetation and exposure conditions.

The variable conditions, exposure and consequences of accidents along a pipeline route result in many challenges related to risk management. Specifically, risk management is difficult as a result of transportation along the pipeline corridor, multiple access routes to the pipeline corridor, unique culture and social issues in various parts of the country, and remote working conditions. Major issues are moving work sites; crossing of different areas of the country with several typical cultural and regional aspects; multiple work sites and the isolation of workers in small groups. These factors make risk management particularly important, but easy to ignore.

In this paper we discuss the major potential risks in every phase of the pipeline construction. The paper describes the company’s process for managing risk during pipeline construction. It identified the limitations of traditional safety management systems in coping with the critical problems related to environmental and safety issues.

Many company are using integrated management systems as the major tools to control risk. Such systems cover health, safety and environmental issues (HSE).

PETROBARS, as the largest Brazilian oil company and one of the leading oil companies in the world, has adopted the HSE system. The system focuses on employee participation in implementation of the HSE system.
A Comprehensive Approach to Monitoring Pipeline River and Stream Crossings
Authors: Sorensen Michelle L. , Malcovish Craig D.
Published: October 2016

There are strict regulatory requirements for pipeline construction at river and stream crossings. The requirements for monitoring, surveillance and maintenance of existing crossings on the other hand are limited to a few lines in Section 10 of CSA Z662-99.

Systematic procedures for assessing stream channel stability are not readily available to the operators of pipelines. As a consequence, many monitoring and inspection programs focus more on detecting exposures than on preventing them.

In this paper, the AEC Pipelines Ltd. approach to monitoring river and stream crossings is reviewed and discussed. The program involves application of basic geomorphic concepts and use of aerial photographs to define channel characteristics at crossing sites and to determine which crossings may be subject to future channel instability or erosion problems. From these in-house evaluations, decisions are made to either proceed with more in-depth assessments by river engineering specialists or continue with routine aerial and ground surveillance. As part of the overall program, procedures for completing routine channel surveys and a checklist of data to be gathered during regular reconnaissance trips have been developed.
Web-Based 3-D GIS and Its Applications for Pipeline Planning and Construction
Authors: Tao Vincent , Wang Ted Q. K.
Published: October 2016

A pipeline project normally not only covers a large geographic range, but also deals with a variety of data sources, such as geological, geographical, environmental, engineering and socioeconomic data. GIS has proven to be the effective approach to integrating, managing and analyzing these heterogeneous data sources. Due to the nature of pipeline applications, the third dimension of geospatial data is of considerable importance for pipeline planning, construction and maintenance. There is an increasing demand for the development of a 3-D GIS for pipeline applications. With the advent of Internet, distributed computing and computer graphics technologies, development of web-based 3-D GIS becomes technologically possible. The combination of 3-D GIS and web-based computing technologies opens a whole new avenue to the pipeline industry. In this paper, we will address the development of a web-based 3D GIS in terms of benefits and technical challenges. The detailed system architecture as well as the algorithms developed is also discussed. Finally, potential applications for the pipeline industry are introduced and a prototype system, GeoEye 3D, developed by the Department of Geomatics Engineering at the University of Calgary is described.
High Resolution Satellite Imagery: From Spies to Pipeline Management
Authors: Adam Steve , Farrell Mike
Published: October 2016

In the past, high resolution satellite imagery was the domain of national security organizations. However, this has recently changed with the launch of Space Imaging’s IKONOS satellite. Launched on September 24, 1999 it is the world’s first commercial high resolution satellite, collecting data at 1-meter black/white and 4-meter multi-spectral.

2000 has the scheduled launch of at least two more commercial high resolution satellites. If these satellites are successfully launched, a buyer will be able to acquire imagery every day of the year (barring cloud cover). As an added convenience, an image user no longer has to buy a massive swath of imagery. For example, IKONOS scenes as narrow as 5km (3 miles) can be purchased. This development has opened the door for corridor applications and has been thoroughly and successfully implemented by TransCanada Pipelines in mapping over 1500km of their mainline.
Pipeline Information System: A Tool for Making Decisions
Authors: Polanco René Perez , Betancourt Enrique Rodriguez
Published: October 2016

The majority of pipeline transportation facilities for natural gas, liquefied petroleum gas and basic petrochemical products were built in Mexico during the 60’ −70. The most recent construction occurred between the 80–90’s. These gas pipelines are located in 24 of the 32 Mexican States, crossing through private property, agricultural fields and sharing right of ways with other Pipeline Companies. The length is up than 11,000 km., beginning in Cactus, Chiapas and ending in Chihuahua. Import/export points are located in Reynosa, Laredo, Piedras Negras and Ciudad Juarez, crossing many populated areas, fresh and salty waters bodies, highways, bridges, areas of irregular topographical terrain. This situation makes operation, maintenance, safety and inspection activities difficult to realize. Therefore, Pemex Gas y Petroquimica Basica established a technical information system, to have integrated digitized pipeline trajectory, on several geographic maps, and technical databases associated related maintenance, operation and safety. Technical consultation is the main project goal, either in headquarters or “in situ” if it were necessary, to aid in decision-making processes, or to take right choices in case of any incident.
Quality Control and Management of Inspection and Data Collection
Authors: Simmons Robert A. , Kania Richard
Published: October 2016

Geographical Information Systems, Data trending, and Risk Assessment Software are now available to help pipeline operators execute safe, cost effective maintenance programs. However, to use these analytical tools effectively, large amounts of data pertaining to the integrity of the pipeline system and its environment are required. For this reason, pipeline rehabilitation programs have evolved into complex data collecting procedures, the success of which depends on the ability to efficiently obtain reliable, consistent and accurate information.

This article will describe new software technology and Quality Control programs, relating to inspection personnel, which have been developed to increase the efficiency and reliability of the information collected during a pipeline excavation.

The pertinent functions of software programs discussed will involve compatibility between databases, on site data validation, code calculations, communications and CAD drawings for a comparison with In Line Inspection results.

As well, the need for quality control or training programs will be discussed addressing both the theoretical and practical applications of pipeline integrity and it’s relevance to quality data collection. Previous projects using these approaches will be presented showing their effectiveness in significantly increasing the efficiency and accuracy of the information collected while reducing overall inspection time and cost.
The Use of GIS and Remote Sensed Data as an Aid to Pipeline Integrity
Authors: Glen S.
Published: October 2016

Geographical Information Systems (GIS) have been in use in some industries for over two decades. Some large scale database or GIS implementations have failed to deliver their full benefits because their scope has often been too wide. Such systems are generally multimillion dollar projects which in turn need ongoing support to maintain the database and administer the system. Where the general needs of a pipeline company are given precedence the specific needs of the integrity department can often be overlooked. As a result the company wide GIS is often of little value for the analysis and management of pipeline integrity data. Recent advances in computing power, software, communications and database design aided by new sources of geographical image data mean that the time is now right for a pipeline integrity specific Geographical Information System.

GIS allows the condition of a pipeline to be viewed in a geographical context and maximises the value of existing data sets. Specific pipeline anomalies can be related to geographical or environmental data such as soil conditions, hydrology, land slip or subsidence. A GIS system used in this way provides a valuable tool to help understand, explain, predict and avoid degradation of a pipeline asset.

New sources of geographical image data such as sub meter, multi spectral optical satellite imagery, synthetic aperture radar data from satellites and thermal data from aircraft systems, can be used to identify ground characteristics or leakage and provide frequent updates to enable change detection and surveillance to be performed. The GIS can be used as a risk assessment and data management tool, which will enable the full benefit to be extracted from each individual data source, ranging from ILI data to CP and corrosion growth data. This new source of information will be an essential aid to pipeline integrity in the new century.

Once implemented the system can be used to perform spatial queries to provide rapid access to the analysis results, confirm code compliance and prioritise corrective action and maximise the efficient use of the resources available.
A Methodology to Maintain Pipeline Integrity at Water Crossings
Authors: Zhou Z. Joe , Beckstead Gary , Westmacott Jason , Samchek Alan , Rizkalla Moness
Published: October 2016

As the pipeline system of TransCanada Pipelines Ltd. (TransCanada) ages, cover at water crossings is continuously being adjusted to dynamic changes in weather patterns and local water crossing hydraulic characteristics. In an increased asset base of over 37 000 km of pipeline, this creates challenges to find and remediate crossings with high risks while maintaining the integrity of the whole system. A methodology has been developed to address the increasing demands of fiscal responsibility and pipeline integrity. The Scour Hazard Database Model (SHDM) provides the necessary tool to provide solutions to both of these challenges. The SHDM provides a stand alone prioritisation tool that is updateable and transparent. It can alert TransCanada to both immediate and potential pipeline exposures, in order that reactive and proactive solutions can be initiated. The SHDM contains descriptive pipeline information, local hydrologic data, channel hydraulic information, and scour hazard logic for over 2350 river and creek crossings throughout Canada. This information is used to produce a final rating value for comparing the potential for vertical and lateral pipeline exposures at each crossing. The vertical scour logic considers age of the crossing, modelled scour, natural degradation and any remedial work to determine the rating value. The lateral erosion logic uses channel form, location, lateral cover distances between the thalweg and pipeline, stream power, age of the crossing, and any remedial work to develop the lateral scour rating value. Furthermore, the exposed pipes are evaluated based on the potential failure mechanisms to determine failure probability. Included in the failure analysis are lateral stability, impact of debris, and fatigue. The failure probability and the consequence of the failure are used to rank the crossings and identify the requirement for maintenance activities.
Full-Scale Fracture Propagation Experiments: A Recent Application and Future Use for the Pipeline Industry
Authors: Johnson D. Michael , Cumber Peter S. , Horner Norval , Carlson Lorne , Eiber Robert
Published: October 2016

A full scale fracture propagation test facility has been developed to validate the design, in terms of the ability of the material to avert a propagating fracture, of a major new pipeline to transport gas 1800 miles from British Columbia in Canada to Chicago in the USA. The pipeline, being built by Alliance Pipeline Ltd, will transport rich natural gas, i.e. gas with a higher than normal proportion of heavier hydrocarbons, at a maximum operating pressure of 12,000 kPa. This gas mixture and pressure combination imposes a more severe requirement on the pipe steel toughness than the traditional operating conditions of North American pipelines. As these conditions were outside the validated range of models, two full-scale experiments were conducted to prove the design. This paper will provide details of the construction of the 367m long experimental facility at the BG Technology Spadeadam test site along with the key data obtained from the experiments. Evaluation of this data showed that the test program had validated Alliance’s fracture control design. The decompression data obtained in the experiments will be compared against predictions from a new decompression model developed by BG Technology. The use of the experimental facility and the model to support future developments in the pipeline industry, particularly in relation to the use of high strength steels, will also be discussed.
Emerging Technologies for Pipe Joints
Authors: Abid Muhammad , Nash David H. , Webjörn Jan
Published: October 2016

In recent years new technologies, novel products, improved services and better contracting procedures are emerging and showing great potential for increased performance and safety. This is increasingly evident for applications in sectors like offshore, petrochemical and refining, ship and submarine building, nuclear power, hydropower, oil and gas transfer lines where failures are can lead to hazards to life. One such technology is a non-gasketed pipe connection and is recognised by the authors as representative of an ‘emerging technology’. It is based on several un-orthodox principles and does consist not only of a pair of welding neck flanges, but of an all-inclusive entire system, comprising bolts, washers, nuts, wrenches, procedures and training.

This paper is based on two years of experimental and finite element studies [Ref 1,2] of both standard/conventional ANSI (gasketed) and modern non-gasketed flanged joints. This has led to a deeper understanding of the requirements for a successful assembly and long term usage. ANSI and VCF joints have been subject to internal pressure, axial and lateral forces, with these loads having been applied both singly and in combinations. Mode of load acting in the joint i.e. static or dynamic has been studied for both kinds of joints. Experimental and analytical results have been compared.

Some practical considerations on the use of important emerging technology i.e. non-gasketed pipe joints in comparison to conventional gasketed systems are presented. Of fundamental importance is an insight into the mechanism of the bolted joint showing the effect from an external load on a preloaded bolt. It is found that it can be made near zero hence, in a properly built, non-gasketed bolted joint a static mode rules, and therefore the stamina of such a joint is unlimited.

Other practical issues of fabrication, handling, surface damage and assembly, have been examined in the lab and on site and a summary of results is presented. In addition a probability risk assessment has been undertaken and results compared with the standard (conventional) ANSI type joints. In addition this paper demonstrates that the novel system is an efficient and well -engineered alternative to traditionally designed joints.
Introduction of Aerial Based and Laser Scan Topographics Survey for Use in Pipeline Route Selection
Authors: Huber James K. , Abukhodair Bassam M. , Dow James W.
Published: October 2016

An innovative technique for rapid and accurate collection of preliminary survey and mapping in pipeline route selection has been developed by Aerotech L.L.C. and implemented by Lakehead Pipe Line Company, Limited Partnership. The technique involves GPS referenced digital imagery and laser scanned topographical data collected on an aerial platform. Accuracy of laser scanned topographical features up to ± 10 cm absolute ± 2 cm relative can be easily achieved. The data is processed and formatted for AutoCAD and GIS applications such as ArcView.
New Technology to Recycle and Rebuild Worn Polyurethane Pipeline Pigs
Authors: Bruce Graham D.
Published: October 2016

SUNcast Polyurethanes Inc. has developed a proprietary process technology that makes it possible to rebuild worn Polyurethane (PU) discs, cups and solid cast pipeline pigs. The technology creates a completely secure bond between the virgin and cured cast elastomer PU enabling rebuilt parts to perform “as new”.

This paper addresses the mechanical characteristics of the bond possible with this technology and offers the results of a case study on a successful program to rebuild over fifty 24″ solid cast pigs for a crude oil pipeline.

Cast elastomer PU is an expensive thermoset polymer which has not been readily recyclable. SUNcast’s technology offers pipeline operators, contractors and inspection companies an opportunity to recycle what is now waste back into high performance pigging products at significant cost savings.
Gulf Water Injection Pipeline and Facilities De-Bottlenecking
Authors: Vargas K. J.
Published: October 2016

Gulf Canada Resources Ltd operates oil processing and water re-injection facilities at Goose River, just South of Valleyview, Alberta. As the oil reservoir is drawn down, the water re-injection is a priority to keep oil production volumes up. The water re-injection pipelines & facilities are extensive & complex systems of headers & pumps at a production Battery, a fresh water Plant & two Satellites. All facilities & injection wells are interconnected by pipeline loops.

A study was undertaken to model the entire water injection system (pipelines & pumps), under a remote & Northern environment. The study included simulation of pipeline route information, flowrates, pressures & ground conditions at strategic locations such as wells & pump discharges. Based on existing conditions a model was configured & calibrated using actual field results. This model was then used to determine the best locations on the pipeline to install added pumping capacity to accommodate the new injection flow rates & pressures.

This paper describes the pipeline facilities and all the steps involved in optimizing the pipeline for water injection purposes. A full description of all facilities together with simulation & calibration techniques will be given in the paper.
Chinese Oil and Gas Pipeline Industry, Its Current Situation and Future
Authors: Huang Zhiqian
Published: October 2016

This paper described the Chinese oil and gas pipeline industry, including its progress, current situation, existing problems and its prospects.
Platte TFI Program: Innovative Solutions to Hydrostatic Testing
Authors: Yasinko Ed A. , Vieth Patrick H. , Dick Dean D. , Nidd Phil G. , Pierantoni Troy D.
Published: October 2016

Platte Pipe Line experienced an operational failure in July 1997. This failure was attributable to operational pressure cycle fatigue crack growth of a hook-crack in the longitudinal seam weld. This defect had grown to failure over a 24-year time period since it had been hydrostatically tested in 1973. In response to this failure, the Department of Transportation (DOT) Office of Pipeline Safety (OPS) issued a corrective order to verify the integrity of this pipeline through either hydrostatic testing or an approved in-line inspection program.

An emerging technology, a Transverse Field Inspection (TFI) tool, was identified as a possible solution to this problem. Even though this inspection tool had not been used previously to identify seam-weld defects, this technology certainly showed promise. The results of our program show that the TFI program resulted in less impact on the operations of this pipeline and provided greater assurance than hydrostatic testing for the long-term operational reliability of this pipeline system. This paper describes the steps required to use this inspection tool for the Platte Pipe Line rehabilitation program.
A Pipeline Dent Assessment Model Considering Localised Effects
Authors: Dinovitzer A. , Bhatia A. , Walker R. , Lazor R.
Published: October 2016

The Canadian Pipeline Design Standard (CSA Z662) [1] requires the repair of smooth dents with depths exceeding 6% of the pipeline’s outside diameter. This limit on dent depth is reduced in the presence of additional localised effects such as pipe wall gouges, corrosion or planar flaws. Furthermore, it has been observed that pipe wall metal loss, planar flaws and weld seam interaction with dents can significantly reduce the service life of a dented pipe segment. A previously developed pipeline dent assessment model, based on the actual dent profile and in-service pressure history applied to non-linear pipe finite element model with a fracture mechanics crack growth algorithm, has been used to explore the consequences of these localised effects. The effects of corrosion (uniform or local pitting), weld seams (including their weld toe stress concentration effects and residual stress fields), planar flaws (cracks) and gouges on the service life of a dent are reviewed in this investigation. The performance of the model is demonstrated based on its agreement with field observations. The dent assessment model application and validation processes has indicated that the model presented here can be reliably used to predict the service life of dented pipelines in the presence of various localised effects.
Fast UT: A New Ultrasonic Inspection Technique
Authors: Sikorski Steve L. , Pfannenstiel Rick
Published: October 2016

The method discussed in this paper uses a simple and concise procedure, which is effective and reliable for locating tip-diffracted signals. The technique utilizes refracted longitudinal waves to both detect and size planar flaws.

Confusing signals which are traditionally associated with angled L-wave techniques, due to mode conversion and direct shear wave reflections, are significantly reduced, while enhancing the ability to detect tip signals by using the FAST™ technique. This technique increases the speed of detection and simplifies sizing compared to traditional shear wave examinations and/or other advanced techniques. FAST™ is an acronym for Flaw Analysis and Sizing Technique.
Ultrasonic Phased Array Technology in the Pipeline Industry
Authors: Sjerve Eric M. , Bryant George F. , Stewart David C.
Published: October 2016

This paper presents an overview of current pipeline inspection techniques, and a more in depth discussion of phased array technology as it applies to the inspection of automated GMAW girth welds in big inch pipelines.
Design Considerations for the Use of Ultrasonic Phased Array Probes in Weld Inspection
Authors: Meyer Paul A.
Published: October 2016

Ultrasonic testing of metal welds has been in use for many years. Scanning methods using both contact and immersion methods are often used at the time of manufacture and also during periodic in-service inspection programs. But because of a variety of component configurations and potential flaw geometries it is often necessary to perform several inspections, each with a different probe configuration to assure adequate defect delegability. It is possible that a properly designed phased array probe can perform several different inspections without changing hardware thereby reducing inspection times. This presentation reviews the design and operation of ultrasonic phased array transducers and the necessary features to achieve the desired performance. Situations in which these probes have already been implemented effectively are also discussed.
Local Stress Effects on MFL Signals
Authors: Clapham L. , Plotnikov A. , Atherton D. L.
Published: October 2016

Of these various factors that influence the Magnetic Flux Leakage (MFL) signal, stress is the most complex and the least understood. Pipe wall operating stresses may exceed 70% of the yield strength, but much higher local stress levels are present around defects because of stress concentrations. Understanding how these stresses affect MFL signals is crucial to accurate defect depth predictions.

We have conducted a number of studies that investigate the effects of bulk and local stresses on magnetic behaviour and MFL signals. Both single defects and interacting (2-hole) defects have been investigated. In addition to MFL studies, we have used a Magnetic Barkhausen Noise (MBN) measurement technique to characterize magnetic behaviour of the sample in response both to local and bulk stresses. In general we find that, for typical inspection geometry (axial magnetizing field and hoop stress) the MFL signal decreases as stress increases. At high flux densities stress effects diminish, but are still significant. Although the general trends described above are common to all defects, different types of defects (through wall hole, blind hole, interacting defects) all display uniquely different MFL stress responses. We attribute this to the difference in local stress distributions (stress concentrations) around these defects.
Enhanced Pipeline Integrity at Lower Cost: A Pipeline Integrity Prioritization Model
Authors: Burdylo Ron S. , Van Aelst Audrey L. L.
Published: October 2016

Strategic, focussed application of pipeline integrity monitoring and mitigation techniques will significantly improve pipeline integrity program effectiveness while reducing overall maintenance costs. These achievements have been demonstrated through the development of Maintenance Prioritization Models (MPM) that pinpoint areas along the pipeline with the highest susceptibility to failure and identify the most cost effective mitigation strategy.

A MPM identifies areas along the pipeline that exhibit a higher relative susceptibility to failure and consequence in the event of a pipeline rupture. Used as part of the owner’s pipeline integrity management program, it assists with optimization, planning and focusing of integrity related preventative maintenance activities. Areas that require short-term mitigation are identified and maintenance budgeting and planning can be prioritized while long-term planning needs are forecast. It enables integrity engineers to manage resources more efficiently by focusing on areas of highest need, thereby extending the useful life of the pipeline section that will, in turn, extend its revenue generation capabilities.
Case History of Local Wrinkling of a Pipeline
Authors: Wilkie S. A. , Doblanko R. M. , Fladager S. J.
Published: October 2016

Enbridge Pipelines (NW) Inc. (formerly Interprovincial Pipe Line (NW) Ltd.) owns and operates a buried 323mm diameter crude oil pipeline from Norman Wells, NWT to Zama, AB. The pipeline is approximately 869 km in length, with the route following a portion of the Mackenzie River Valley in the Northwest Territories. The pipeline routing is through discontinuous permafrost that has the potential to interact with the pipeline through frost heave, slope movement and thaw settlement that can produce extreme structural stresses in the pipe wall. Given the proper conditions, these stresses may localize and the pipeline will deform plastically, causing pipe wall wrinkling.

This paper reviews the general structural design and discusses the inspection and monitoring of the structural integrity of the pipeline, as well as the intervention criteria used to determine when structural mitigation is required. This case study will discuss the discovery of a wrinkle from internal inspection pig data, field dig verification, installation and monitoring of field instrumentation and the pipeline repair technique that was utilized.
Pipeline Inspection and Rehabilitation Using Clock Spring®
Authors: Porter Patrick C. , Mitchell Jesse L.
Published: October 2016

This paper reviews the Clock Spring® repair system showing how it works and how it can be an effective component of a pipeline integrity program. It also outlines a Pipeline Integrity Program that is effective for TEPPCO and can be helpful to pipeline operators in the development of other pipeline integrity programs.

Using high-resolution magnetic flux leakage inspection tools and the Clock Spring® pipeline repair system, TEPPCO’s ten-year pipeline integrity program is ahead of schedule and significantly under budget. The use of advanced technology, combined with efficient planning, has yielded a unique systematic approach to pipeline integrity enhancement.
Recent Changes in Code Requirements for Repair of In-Service Pipelines by Welding
Authors: Bruce William A.
Published: October 2016

The API code requirements for repair of in-service pipelines by welding were recently up-dated. The 19th edition of API 1104 - Welding of Pipelines and Related Facilities - includes a new appendix (Appendix B) titled In-Service Welding, which is intended to eventually replace API 1107 - Pipeline Maintenance Welding Practices. Work is also presently underway to up-date the requirements for weld deposition repair in ASME B31.8 - Gas Transmission Systems. This paper reviews the rationale behind these changes and provides a brief summary of their primary features.
Analysis of Hydrogen Permeation Through Pipeline Steel in Near-Neutral pH SCC Environments
Authors: Cheng Yufeng , Yang Lin , King Fraser
Published: October 2016

The Devanathan-cell technique has been used to determine the permeation flux of hydrogen through X-65 steel at the open-circuit potential in solutions associated with near-neutral pH stress corrosion cracking. The effects of organic material and microbial activity were also simulated by suitable additions to the solution. A model based on a constant-concentration boundary condition was found to fit the experimental data better than one based on a constant flux condition. The addition of 9,10-anthroquinone-2,6-disulphonic acid to the solution to simulate the effect of organic material lowered the hydrogen permeation flux. Sulfide additions to simulate the action of sulfate-reducing bacteria initially increased the rate of hydrogen permeation, but subsequently resulted in a decrease in permeation current. The hydrogen permeation rate measured on the original oxide-covered surface is lower and more variable than that on polished surfaces. Corrosion rate measurements were also made, from which the fraction of atomic hydrogen diffusing through the specimens was estimated. The results are discussed in terms of the mechanism of hydrogen evolution and absorption.
Hydrogen Permeation Behavior of X-70 Pipeline Steel in a Near-Neutral pH Soil Environment
Authors: Chen Weixing , Wang Sheng-Hui , King Fraser , Jack Tom R. , Wilmott Martyn J.
Published: October 2016

This paper reports the hydrogen permeation behavior of an X-70 pipeline steel in a synthetic near neutral pH field solution under both galvanostatic and potentiostatic conditions. The hydrogen flux through the steel exposed to the solution is influenced by the chemical reactions at the steel surface on the charging side. Results from tests done under potentiostatic and galvanostatic conditions were compared to predictions based on different boundary conditions assumed in solving Fick’s diffusion equations. Constant concentration boundary conditions gave the best fit. It was also found that the diffusible hydrogen generated in a near neutral pH soil environment is likely to be 3 to 10 times lower than the minimum hydrogen concentration required to initiate hydrogen blistering in pipeline steels.
Theoretical and Experimental Study of Stress Corrosion Cracking of Pipeline Steel in Near Neutral pH Environment
Authors: Zhang B. , Fan J. , Gogotsi Y. , Chudnovsky A. , Teitsma A.
Published: October 2016

Stress corrosion cracking (SCC) is a complex phenomenon that involves various interacting physical and chemical processes. There is a combination of determinism and stochasticity that results in SCC colony evolution. A statistical model that generates a random field of corrosion pits and crack initiation at randomly selected pits is proposed in this work. A thermodynamic model of individual SC crack growth has been recently developed within the framework of the Crack Layer theory. Mathematical realization of the SC crack growth model is presented in the form of relations between the crack growth, hydrogen diffusion and corrosion rates on one hand and corresponding thermodynamic forces on the other. Experimental program for determination of the kinetic coefficients employed in crack growth equations is briefly reported. Finally, application of the individual crack growth law to random configuration of multiple cracks results in a simulation of SCC colony evolution, including a stage of the large-scale crack interaction. The solution of the crack interaction problem via FRANC2D Finite Element Methods results in a computer simulation of multi-crack cluster formation within the colony.
Northstar Development Pipelines Limit State Design and Experimental Program
Authors: Nogueira André C. , Lanan Glenn A. , Even Tom M. , Fowler Joe R. , Hormberg Brett A.
Published: October 2016

BP Exploration (Alaska) Inc. (BPXA) and its Northstar Project Alliance contractors started field construction of the Northstar development in January 2000 (Lanan et al. 2000). In April 2000, the offshore section of the Northstar pipeline reached Seal Island, located in 11 m water depth Northwest of Prudhoe Bay. Seal Island is in the Beaufort Sea, 9.7 km offshore from the shore crossing at Point Storkersen, on the North Slope of Alaska. Design, testing and permitting activities required multiple years leading up to this first of it kind pipeline construction project. Figure 1 shows the offshore pipeline welding spread working on the floating sea ice surface, similar to the conventional procedures used on the overland portion of the Northstar pipeline. This paper presents the limit state design of the offshore pipelines and the associated full-scale experimental program, which demonstrated that the pipelines can safely withstand operational bending strains up to 1.8%.
Aging, Pressure and Temperature Effects on the Thermal Performance of an Insulated Flowline
Authors: Wang X. , Perera M. R. , Prescott C. N. , Raborn G. O.
Published: October 2016

Flowline thermal insulation is essential for deepwater field development when long distance subsea tieback is required. Proper flowline insulation design can prevent hydrate and wax formation during production, as well as provide sufficient time, in the event of an unplanned well shut-in, for resuming production before the product temperature drops below the critical temperatures. Although many insulated flowline configurations, (i.e., insulated pipe-in-pipe and insulated multi-flowline bundle) have been installed, insulation designs are usually based on insulation material technical data obtained at standard conditions. Few publications are available on the effects of insulation material aging, operation temperature, and environmental pressure (in the case of a pressurized annulus of pipe-in-pipe or bundle) on the flowline insulation performance.

In this paper, such effects on the thermal insulation properties of an insulated flowline, in both steady state and cool down conditions, are discussed. Insulation material thermal conductivity test data are presented at various pressures, temperatures, and aging effects (duration between manufacture and test). The test data are applied to typical flowline insulation designs and comparisons made with cases when these effects are neglected. Based on the test and analysis results, recommendations are made for insulated flowline designs.
Numerical Simulation of Oil Slicks Trajectories: A Tool for Risk Assesment in Pipeline Breakdown
Authors: Paladino Emilio Ernesto , Maliska Clovis Raimundo
Published: October 2016

The aim of this paper is to present a mathematical model and its numerical treatment to forecast oil spills trajectories in the sea. The knowledge of the trajectory followed by an oil slick spilled on the sea is of fundamental importance in the estimation of potential risks for pipeline and tankers route selection, and in combating the pollution using floating barriers, detergents, etc. In order to estimate these slicks trajectories a new model, based on the mass and momentum conservation equations is presented. The model considers the spreading in the regimes when the inertial and viscous forces counterbalance gravity and takes into account the effects of winds and water currents. The mass loss caused by oil evaporation is also considered. The numerical model is developed in generalized coordinates, making the model easily applicable to complex coastal geographies.
Leak Detection Systems for Short Pipelines
Authors: Baptista Renan Martins
Published: October 2016

This paper describes procedures developed by PETROBRAS Research & Development Center to assess a software-based leak detection system (LDS) for short pipelines. These so-called “Low Complexity Pipelines” are short pipeline segments with single-phase liquid flow. Detection solutions offered by service companies are frequently designed for large pipeline networks, with batches and multiple injections and deliveries. Such solutions are sometimes impractical for short pipelines, due to high cost, long tuning procedures, complex instrumentation and substantial computing requirements. The approach outlined here is a corporate approach that optimizes a LDS for shorter lines. The two most popular implemented techniques are the Compensated Volume Balance (CVB), and the Real Time Transient Model (RTTM). The first approach is less accurate, reliable and robust when compared to the second. However, it can be cheaper, simpler, faster to install and very effective, being marginally behind the second one, and very cost-efective. This paper describes a procedure to determine whether one can use a CVB in a short pipeline.
Quasi-Steady Flow in Hydraulic Systems Using MOC
Authors: Wylie E. Benjamin
Published: October 2016

The Method of Characteristics (MOC) is utilized effectively in many industries to calculate hydraulic transients in almost all pipeline systems. Recently it has been suggested as a suitable calculation procedure for long term (extended time) quasi-steady flow problems. It might serve as an alternative approach to using rigid water-column (lumped inertia) calculations, or to integrating over time with a series of steady state calculations, which are two procedures receiving recent attention. This paper provides a unique approach within the MOC framework, by modifying terms in the pipeline partial differential equations. When carried through the MOC it leads to a minor modification in a transient code by introducing the two new parameters. The method is developed and applied to a network example herein.
False Flow Registration in the Return Run of a Meter Station Due to Pulsation Amplifications
Authors: Botros K. K. , Geerligs J.
Published: October 2016

Meter stations located close to producers of natural gas often experience pulsation problems due to flow oscillations generated by reciprocating compressors required to pressurize the gas for pipeline transmission. The present paper deals with a unique metering pulsation problem in that despite the low level of pulsation that is not impairing the accuracy of the primary metering device (orifice) on the main run, a false registration of flow in the return run is observed. This was found to be caused by an acoustic resonance in the return run during the normal forward flow operation of the station. Field measurements of pulsation levels were taken at several locations in the meter station and a flow-acoustic analysis was conducted on the entire station using a flow-acoustic simulator (PULS). Investigation into the cause of the check valve chattering on the return run and registration of back flow were clearly identified as being caused by the return run tuned to a quarter wave length corresponding to the 1st harmonic of the pulsation source. It was found that simple pulsation abatement devices such as a Kotter plate, or even conventional flow conditioners such as NOVA 50E flow conditioner and coalescing filters (though not intended to be used as pulsation abatement devices) were not suitable to alleviate the problem. The problem was best solved in this case by a conventional acoustic expander inserted on the return run which resulted in completely eliminating check valve chattering and the false flow registration in the return run since implementation. It was concluded that it is important to recognize the nature of an acoustic problem before implementing general abatement devices that were sold as ‘cure-for-all-problems’.