bluuebunny/crossref_metadata_2025 huggingface dataset:
Building a Leakage Detection System Using Ensembles: A New Way
Authors: Bomfim Carlos H. M. , Caminhas Walmir Matos , Rodrigues de Menezes Benjamim , Laurentys de Almeida Carlos Alexandre
Published: December 2008

Pipeline leakage is a demand from governmental and environmental associations that petroleum companies need to comply. Recent accidents with Petrobras pipelines increase local demand for leakage detection system. Due the high accuracy on detecting leakage required from that system is necessary to set a procedure that once applied will achieve the best performance considering the quality of the installed instrumentation. This paper describes a procedure to set such system in order to accomplish with the legal requirement keeping high reliability during normal and failure operations. Nuisance alarms are kept at low value while minimum leakage detection is too small. To do that the described system uses a set of models acting as specialists each one observing and diagnosing pipeline leakage. This system also validates the operations according to the business rules. System uses a set of tools, fuzzy logic, neural network, genetic algorithm and statistic analysis, to execute its function. The usage of an optimization tool, genetic algorithm in this case, helps the designer to set a function alarm that uses a statistical approach to assure a reliable performance when detecting the leakage and keeping the nuisance alarm closes to zero. Both qualities make the system highly reliable since once it generates one alarm there is a likelihood of almost a 100% that the event is true. Instead of using the common two parameters alarm, threshold and timing, this system uses pattern recognition to verify the fault or leak condition. The detectable leakage value is function of the difference between the flow measurement at the inlet and the outlet of the pipeline. The minimum leakage detectable is constant and equal to 1.4 times the standard deviation of the error between this two meters for 0.2% of nuisance alarm. In the application it is able to alarm when a leakage of 2% of the total flow happens in a time bellow 5 minutes. If allowed a level of 5% of nuisance alarms the system is able to detect a leakage of one standard deviation of the error. That represents the mentioned amount of 1.4 times the standard deviation of the error. The system is in operation supervising pipeline in a Brazilian installation.
Predicting Near-Neutral pH SCC Conditions Under a Disbonded Coating on Pipelines
Authors: Song Fengmei , Sridhar Narasi , Been Jenny , King Fraser
Published: December 2008

Cathodic protection (CP) shielding and the presence of carbon dioxide (CO2) in the soil environment are necessary for the occurrence of near-neutral pH stress corrosion cracking (NNPHSCC). Quantitative understanding of the relationship between external conditions, coating deterioration and NNPHSCC is emerging but needs further improvements in modeling and experimental tool. This paper is aimed at understanding the environments initiating the NNPHSCC. New experimental results are presented on crevice chemistry due to the degradation of the mastic of a commercial high-density polyethylene (HDPE) coating and due to CO2 penetration into a disbonded crevice through the coating. Also presented are the results obtained from a comprehensive model, TECTRAN, on the effect of CO2 penetration into a crevice through the holiday alone and through both the holiday and the coating. The experimental results show that as the coating mastic degrades in the soil solution, the solution pH decreases within a few days from about 9 to a steady-state value of about 7.5. The Co2 diffusion through a 0.3 mm commercial HDPE coating is rapid, with a decrease of the soil solution pH from 9 to 5 within a matter of days (external CO2 pressure is 1 atm). The model results show that the presence of CO2 in the soil (0.05 atm partial pressure) can reduce the crevice solution pH to near neutral due mainly to its penetration through the coating, confirming previous hypotheses regarding its role in initiating NNPHSCC.
In Salah Gas Export Pipeline Project
Authors: Khedr Emad , Laurijssen Jack
Published: December 2008

The In Salah Gas field in Southern Central Algeria is a major gas discovery. Seven proven gas fields will deliver a total of 9 billion cubic meters of dry gas annually. The gas, will be transported to the market by a pipeline connecting the gas field to the major collection point at Hassi R’Mel. The gas will be fed into major gas transport lines at this point for delivery to market in Europe via the trans-Mediterranean pipeline systems. When full deliveries of In Salah gas are made from the field, they will increase the total gas exported from Algeria by about 15%. BP and Sonatrach jointly developed the project, and the In Salah Project opens a new area of Algeria, to development.
Electromagnetic Surface Method for the Pipeline Periodical Inspection Based on the Heterogeneous Transmission Line Model
Authors: Mousatov Aleksandr , Nakamura Edgar K. , Shevnin Vladimir
Published: December 2008

The superficial electromagnetic methods are widely applied for non-destructive control of pipeline technical condition. For this purpose we have developed the theory and field technology for the pipeline inspection that allows: 1) determining the pipeline trajectory (plane position and depth), 2) delimitation of pipeline intervals with an insulation coating damage, and 3) estimating the condition of a cathodic protection system. The proposed method is based on the approximation of a metallic pipeline by a heterogeneous transmission line with variable distributed parameters: resistance and inductance along a tube (tube wall thickness) and leakage conductance. The field operations consist in measurements of magnetic field above a pipeline and voltage only on the control posts. The interpretation process includes the iterative inversion of the magnetic component in order to determine the pipeline depth and current distribution along pipeline. The current difference corresponds to leakage current and allow estimate the leakage resistance. We illustrate the practical application of this method using the obtained results for pipeline inspections in Mexico. Based on the voltage and current simulations for the infralow-frequency band (0–1kHz) we have evaluated the feasibility of the time lapse measurements of the magnetic field in some fixed points for the early prediction of an insulation damaging process.
Development of High Strength Material and Pipe Production Technology for Grade X120 Line Pipe
Authors: Hillenbrand Hans-Georg , Liessem Andreas , Biermann Karin , Heckmann Carl Justus , Schwinn Volker
Published: December 2008

The increasing demand for natural gas will further influence the type of its transportation in the future, both from the strategic and economic point of view. Long-distance pipelines are a safe and economic means to transport the gas from production sites to end users. High-strength steels in grade X80 are nowadays state of the art. Grade X100 was recently developed but not yet utilised. The present-day technical limitations on the production of X120 line pipe namely the steel composition, the pipe forming and the welding are addressed in this paper. Production test results on X120 pipes are presented to describe the materials properties. A low carbon and low PCM steel with VNbTiB microalloying concept is used. In the plate rolling the main attention is turned to the heavy accelerated cooling. The large spring back that occurs during the U-forming step of the UOE process is one of the most complex aspects in forming X120. To handle this aspect FEM calculations were used to modify the forming parameters and to optimise the shape of the U-press tool. For optimising the existing welding procedure with respect to an avoidance of HAZ softening, a low heat input welding technology and new welding consumables were developed.
The Effect of a Discontinuous Welding Technique on Stress Levels of a Hot Tap Tee
Authors: Xue X. L. , Sang Z. F. , Jiang W. Z.
Published: December 2008

With the development of petrochemical industry, the hot tapping technology has been widely used. A hot tapping is a technique that allows establishing a branch connection to a live pipeline. As it is a technology without halting transportation, it can avoid large economic losses and serious air pollution. When an operation of hot tapping is performed, a technology of discontinuous welding is sometimes used to reduce the localized high temperature that may cause burn-through of pipe. The purpose of this paper is to investigate whether the structure fabricated by discontinuous welding can work safely. Simulation of discontinuous welding was conducted to compare the temperature and stress distribution between continuous and discontinuous welding. It can be concluded that the temporary high temperature can be reduced effectively by discontinuous welding. However, due to frequent arc starting, a larger residual stress is resulted in. The stress level under internal pressure was studied by experiment using stress-gauging method. And the internal pressure was imposed by a high-lift pump. The failure load of the test model was 24.0MPa. Finite element simulation was also conducted to study the stress level under internal pressure. Then a comparison between experimental and FEA results was made. The experimental and FEA results indicate that the maximal stress occurs at the intersection area of the branch and run pipe. And it also can be seen that the results of radial deformation in the cross section are in good agreement. The metallurgical structure study shows that the welding and heat-treating procedures were proper. It can be concluded from this study that although the stress level is high under operating pressure, the structure can undergo the operating pressure safely.
Modernization Process for Oil Pipelines
Authors: Hylton Michael
Published: December 2008

Many operating oil pipeline systems in North America, and throughout the world were designed to former pipeline codes, many over 30 years ago, which were less stringent than those in force today. Pipeline integrity management is an extremely important function for pipeline operators, and there are enormous advantages for pipeline owners to modify and improve the integrity of their existing pipeline systems and to meet the present-day requirements. A life-cycle analysis process has been developed, which can extend the life of the pipeline, while bringing it into regulatory compliance with present-day pipeline codes. This process avoids the necessity of (expensive) pipeline replacement programs. This process can also be applied to “non-loggable” (oil or gas) pipelines, to compliment external/internal direct assessment techniques.
Environmental Risk Analysis and Risk Assessment for Osbra Pipeline: A New Approach
Authors: Rodrigues Torres Carlos Alberto , Teruya Yogui Regiane Tiemi , Mendes Renato , Rocha Carneiro Maria Eula´lia , de Oliveira Wilson Jose´
Published: December 2008

Osbra pipeline (Oleoduto Sa˜o Paulo – Brasi´lia), about 1000 Km long, is one of the main pipelines of Petrobras Transportes S. A. - Transpetro and its function is to carry gasoline, diesel oil, aviation kerosene and liquefied petroleum gas throughout the Center-West region of Brazil. As it crosses several states of Brazil (Sa˜o Paulo, Minas Gerais and Goia´s) and Federal District (Brasi´lia), the process of renewal of the environmental license at the federal level required a series of environmental studies. Accordingly, a new study is being performed, considering, in addition to the already consecrated Quantitative Risk Assessment, a new methodology for recognition and analysis of the vulnerable environmental elements along the pipeline right-of-way in what concerns oil spill. This study intends to present the aforementioned methodology according to the following topics: Characterization of the undertaking and of the surrounding region; identification of the notable points; identification of the sensitive environmental elements in the hydrographic basins; Preliminary Hazard Analysis; definition of accident scenarios; dimension of possible leaks along the pipeline right-of-way and their consequences (physical effects); calculation of frequencies; calculation and evaluation of risks (social and individual); classification of environmental sensitivity; contingency actions analysis and conclusions. Development of this work brings as a result a more detailed knowledge of the consequences of an occasional accident arising from pipeline related activities, to the end of preventing and protecting the vulnerable elements (man and environment) along the pipeline right-of-way.
Reliability-Based Evaluation of Pipelines Using Above Ground Inspection Methods for External Corrosion
Authors: Fuglem Mark K. , Stephens Mark J.
Published: December 2008

Above ground inspection methods such as Close Interval, AC Current Attenuation, Direct Voltage Gradient and Pearson surveys are often employed to examine pipelines for external corrosion, especially when in-line inspection and hydrotesting are not feasible. Compared to in-line inspection, these methods can be superior in identifying general areas of corrosion, however, they generally have a higher probability of missing significant defects. This paper examines the use of quantitative reliability-based methods for assessing the integrity of pipelines that have been inspected using above ground methods where these inspections are followed up by a selective excavation and defect sizing process. Special consideration is given to the inference of the size distribution of undetected defects when the number of detected defects is small.
Ductile Cracking Evaluation of X80/X100 High Strength Linepipes
Authors: Sadasue Teruki , Igi Satoshi , Kubo Takahiro , Ishikawa Nobuyuki , Endo Shigeru , Glover Alan , Horsley David , Toyoda Masao
Published: December 2008

The ductile cracking behavior of girth weld joints, in X80 and X100 grade linepipe, was investigated using single edge notched (SENT) specimens, notched round bar (NRB) specimens and wide plate (WP) specimens. FE analyses were carried out to evaluate critical conditions for ductile cracking at the notch tip. The effect of Y/T ratio of base material on ductile cracking for welded joints was also studied. Ductile cracking from the notch tip in WP specimens can be estimated by using the critical equivalent plastic strain, which can be obtained from SENT or NRB specimens. In addition, a simplified prediction method for ductile cracking by using effective opening displacement was proposed and its validity demonstrated by comparison to the equivalent plastic strain at the notch tip. With respect to the influence of material properties on ductile cracking behavior, deformability of joint to ductile cracking was enhanced by reduction of Y/T ratio of base material. Based on the experimental results and FE analyses, pipe design to prevent ductile cracking from surface flaws under large deformation was discussed.
Rehabilitation and Certification of the PGPB Cactus-San Fernando Gas Pipeline System
Authors: Graciano Luis Sanchez , Clyne Alasdair , Cazenave Pablo , Kania Richard , Willis Susy
Published: December 2008

The Cactus-San Fernando gas pipeline system was constructed between 1977–79 in 42 and 48-inch diameter pipe. The pipeline extends for a total length of 650 km in 10 piggable sections. This paper details the work conducted to allow the pipeline to be re-validated to its original design pressure. The overall aim of the project was to demonstrate the future integrity of the pipeline system. The scope of the study was extensive and required innovative project management techniques. It encompassed caliper inspections and high-resolution magnetic inspection, the provision of global positioning surveys (GPS), Pipeline Integrity Assessment including repair schedules, future corrosion prevention and reinspection strategy and pipeline rehabilitation including non-destructive examination (NDE), material testing and repairs. The whole process was reviewed and ratified by an approved Certifying Company who issued a Certificate of Mechanical Integrity, valid for a fixed period of 2 1/2 years.
Development and Validation of a Pipeline Buckle and Wrinkle Assessment Model
Authors: Dinovitzer A. , Fredj A. , Lazor R. , Doblanko R.
Published: December 2008

Inspection has revealed pipeline buckles and wrinkles promoted by thermal loads, differential settlement, slope movement and other pipe-soil interaction modes, as well as, cold field bends during construction. While all agree that pipeline wrinkles are undesirable, the urgency of their repair is not commonly understood. In general, it is accepted that the onset of wrinkling does not result in a loss of integrity because pipeline steels are adequately ductile to support large monotonic strains. It is also known that loading is displacement-controlled, thus applied load relief occurs during wrinkle formation. Although failure can occur with only a few strain reversals, the low loading frequency provides time to react. This paper will describe the steps and tools required to define the maintenance requirements for a pipeline wrinkle or to evaluate the effectiveness of remediation techniques. The paper will focus on the results of a preliminary wrinkle model development project aimed at assembling a practical technique capable of predicting the service life of a buckled or wrinkled pipe segment. The LS-DYNA non-linear finite element (FE)-based numerical wrinkle and buckle formation and growth model, developed at BMT Fleet Technology Limited, will be described along with its validation through comparison with full-scale trials and existing design criteria. The paper also discusses the use of the FE model predicted through-life wrinkle behavior to estimate the wrinkle service life and describe the way forward for the further development and implementation of this approach.
Northern Exposure: Monitoring and Testing a Subarctic Liquids Pipeline
Authors: Barlow Rick , Farquhar Ted , Tleukulov Anar
Published: December 2008

The subarctic location of Enbridge’s Norman Wells pipeline provides unique conditions affecting both construction and operations. These include the huge variations in annual air temperature, permanently frozen ground (permafrost), hundreds of river crossings and potential slope instability. The regulatory authorities recognized this environmental sensitivity and stringent conditions for construction and operation were applied. In this difficult environment, loss of integrity must be detected rapidly and at low thresholds. To ensure that integrity monitoring maintains or improves these thresholds, frequent testing is necessary. Testing of the integrity of this remote northern oil pipeline provides significant operational challenges. This remote 869km (540 mile) NPS12 crude oil pipeline has been operating in the Canadian subarctic since 1985. This paper will outline the implementation, assessment and future directions of the integrity monitoring testing of the pipeline’s leak detection capability. The history of this pipeline in the Canadian Northwest Territories will be outlined with emphasis on the special regulatory issues of this sensitive sub arctic environment. The development of a Computational Pipeline Modeling (CPM) leak detection system to meet these regulations will be summarized with reference to the guidelines of CSA Z662, Appendix E. A central component of meeting this regulatory requirement is an annual test program that uses controlled fluid withdrawal to test the CPM system and operational responses. The special methods and procedures used to meet the challenges of this program will be noted. The extent and frequency of testing make this probably one of the most tested liquid pipeline leak detection systems in the world. These controlled fluid withdrawal tests are used to enhance the Enbridge response to operational emergencies. Many factors must be considered when designing these tests. A detailed description of the preparation and field logistics required for the pipeline CPM test will be presented. The special needs of conducting tests in an environmentally sensitive region will also be outlined. A review of how these tests address the considerations of API 1149 and API 1155 are summarized. Since pipeline completion, over 70 test events have been conducted. A recent case study will detail some of the issues associated with testing. Future plans for enhancements using additional testing methodologies will be presented with particular mention of a simulation-based alternative.
Manufacturing and Use of Spiral Welded Pipes for High Pressure Service: State of the Art
Authors: Knoop Franz Martin , Sommer Baldur
Published: December 2008

The HTS (Helical Seam Two Step) manufacturing process is used for the production of HSAW-pipes for high pressure service since 1987. The production process is split into pipe forming combined with continuous tack welding followed by submerged arc welding. The process has been continuously developed further. Details of this modern technology are described and qualitative and economical advantages over the conventional process are explained. The benefits of the existing network with steel plant and hot rolling mill as well as the quality controls, process automatisation and new NDT-equipment used in the pipe production are highlighted. Statistics on mechanical, chemical and dimensional properties of HTS pipes are presented to furnish proof of the uniform and well balanced profile of this product. Results from hot and cold bending on site, field weldability trials and tests related to the safety of spiral pipes are discussed. Results and experiences with the application of three-layer coatings (especially HDPE-high density polyethylene) on spiral pipes are also presented. Actual examples for the use and application of spiral welded pipes in international gas and oil projects are presented and an outlook on future development trends is given.
Prediction of Corrosion Defect Growth on Operating Pipelines
Authors: Fenyvesi L. , Lu H. , Jack T. R.
Published: December 2008

Integrity management is based on the ability of the pipeline operator to predict the growth of defects detected in inspection programs on an operating pipeline system. Accurate predictions allow targeted interventions to be scheduled in a cost effective and timely fashion for those defects that pose a high potential risk. In this paper two distinct theories are described for predicting the development of corrosion pits on an operating pipeline. The first theory corresponds to the traditional approach in which the past growth behaviour of each defect is used to predict the rate of its future development. In this theory each defect is assumed to have its own unique corrosion environment in which only a very limited range of corrosion rates will be seen. In the second approach, this assumption is not made. Instead any corrosion defect is allowed to grow at any likely rate over any time interva. In this approach an arbitrary selection of corrosion rates derived from the overall profile of past rates seen for all defects is applied to each defect over time. Predicted distributions derived by computer simulation of the initiation and growth of corrosion defects according to each theory have been compared to an actual defect depth distribution derived by in line inspection (ILI) of an operating pipeline. The success of the two models is compared and implications for pipeline integrity management are discussed.
Influence of the Distance of the Chromatographic Analysis Point on the Energy Flow Calculation in GASBOL
Authors: Coutinho Dura˜o Marcelo , Longa Junior Mario Veiga , Palhares Julio Ce´sar Costa de Mello , Nunes Ildemar Pinto
Published: December 2008

In Bolivia-Brazil Gas Pipeline the gas samples are only taken in two points along in its all extension, the first is located just at the entrance of the gas pipeline in Rio Grande, Bolivia, and the second sampling point is 550 km far from the first, exactly on Brazil’s border, where the pipeline comes to the TBG’s property. In Brazilian ground, the pipeline has no more additional inlet point and after this point in the border, no more any additional samples are taken. Nowadays, the measurement process has been simplified by the use of the gas composition analyzed in the day of the sampling as exactly the same gas that is filling out the whole gas pipeline at that moment. This simplification creates a mistake that is expected, but until then it had not been calculated. The present paper has an objective to identify the sampling point influence in the energy delivered in TBG’s city gates. To have a better analysis of this influence it is necessary to calculate the gas residence time from the border to the specific delivery point. This residence time is determined by simulation. Considering the difference among the energy used in the revenue and the energy calculated by the new gross heating value adjusted by the residence time of the gas, this paper concluded that the influence of the sampling point in the calculation of the delivered energy is small because the variation of the gross heating value along the period has also been low.
Handheld PC Used in Field Maintenance of the GASBOL Pipeline: A Case Study
Authors: Ribeiro Robison T. , Single Marcio , Sima Reinaldo F.
Published: December 2008

One of the most important challenges in maintenance and integrity is the correct register of maintenance data. Information about failures, diagnostics and services execution are extremely important for the background history of equipments and future analysis. Field personnel usually supply the information in the CMMS (Computerized Maintenance Management System) in the form of few words (or key words) written in a notepad, agenda or at the backside of a maintenance work order. Therefore, most of the time the quality of data is very low, registries are very poor, information is generic and does not add value to the background history of equipment. Sometimes these data are not really true; they are only remembrances from the maintenance worker’s memory. In natural gas pipeline companies, like TBG, with large extensions of pipes and installations distributed so far from each other it is usual that maintenance personnel go to the field job and sometimes do not come back to the office at the same day. In addition, the need to access the corporate network to input maintenance data in the Maintenance Module of Enterprise Resource Planning means that maintenance registries are something that do not flow easily from field to database. Technicians also spend a lot of time in front of the computer decreasing their productive working hours. Being aware of the importance of data to a consistent integrity pipeline program and to solve the problems related above, TBG implemented Maintenance in the Palm of the Hand project and distributed handheld PCs to all technicians, with software that works like an electronic maintenance work order. This system permits to collect maintenance data in real time (timesheet, measurements and information about the job and related problems) and also providing important information to help technicians perform their jobs (equipment data, set points and task list). If necessary, they can start a maintenance request. At any moment it is possible to connect to the corporate network and download data to CMMS. This project allowed TBG to increase quality and reliability of maintenance data and speed of information flow from field to CMMS, eliminating the need to print work orders and data sheets, increasing the productivity of technicians and reducing the time spent on boring tasks such as taking notes.
Automatic, Non-Intrusive, Flame Detection in Pipelines
Authors: Morgan M. D. , Mehta S. A. (Raj) , Al-Himyary T. J. , Moore R. G. (Gord)
Published: December 2008

Many methods of flame detection are available. Unfortunately, few offer remote, non-line-of-sight, detection. In cases where flammable mixtures are transported within tubing (such as flare lines, storage tank vents, air drilling, and improperly designed purging operations) there is often no means by which combustion can be detected. This is a significant deficiency in some applications. If the mixture were to ignite, the results could be catastrophic. To address this problem, combustion noise is being investigated at the University of Calgary as a possible means of detecting flames within tubing. An experimental study has been completed that shows that combustion noise can be distinguished from other sources of noise by its inverse power law relationship with frequency. A robust algorithm has been developed that, when combined with high-speed pressure measurements, provides early detection of flames. When combined with other filters, the algorithm can automatically separate combustion noise from other sources of noise. In this paper, a stop band filter was used to remove the noise created by a fluttering check valve.
Implementation of Knowledge Portal Technology Software for Pipeline Integrity Data Management
Authors: Stewart Wendy , Keller Jennifer
Published: December 2008

Canspec’s Pipeline Integrity Group typically collects data on more than 500 dig sites annually, which includes analyzing and maintaining thousands of records for each major client. Additionally, Canspec also provides time sensitive information and guidance to its clientele related to repairs, pipe replacement, and collaborative pipeline integrity research. In order to improve data management and decrease reporting time on this large volume of data, Canspec initiated a short-term pilot project in collaboration with Bridge Solutions to develop an internet-based portal program called EKP3.0. The web portal is a fast and efficient way to create a secure customized search engine and web directory for complete data management, which is also accessible to the large number of field crews performing this work. Since implementation in April 2003, the EKP3.0 software has reduced overall reporting time by more than 35%. Due to the overwhelming success of the short-term pilot project, Canspec has adopted this software as a long-term solution for ongoing data management. This paper will compare previous data collection, delivery, and reporting practices with the current internet-based EKP3.0 software process. It will also elaborate on future plans to design an XML (Extensible Markup Language) data transfer format, which will reduce the labour-intensive peer review process, automate the customization of final reports delivered to the client, and create a rules-based field data collection application.
Optimizing a Pipeline Operation by Constraint Logic Programming (CLP) and Mixed Integer Linear Programming (MILP)
Authors: Magata˜o L. , Arruda L. V. R. , Neves F.
Published: December 2008

This paper addresses the problem of developing an optimization structure to aid the operational decision-making in a real-world pipeline scenario. The pipeline connects an inland refinery to a harbor, conveying different types of products (gasoline, diesel, kerosene, alcohol, liquefied petroleum gas, jet fuel, etc). The scheduling of activities has to be specified in advance by a specialist, who must provide low cost operational procedures. The specialist has to take into account issues concerning product availability, tankage constraints, pumping sequencing, flow rate determination, and a series of operational requirements. Thus, the decision-making process is hard and error-prone due to the diversity of aspects to be considered. Nevertheless, the developed optimization structure can aid the specialist in solving the pipeline scheduling task with improved efficiency. Such optimization structure has its core in a novel mathematical approach, which uses Constraint Logic Programming (CLP) and Mixed Integer Linear Programming (MILP) technologies in an integrated CLP-MILP model. In particular, the integration of CLP and MILP technologies has been recognized as an emerging discipline for achieving the best that CLP and MILP can contribute to solve scheduling problems [1]. The scheme used for integrating CLP and MILP is double modeling [1], and the combined CLP-MILP model is implemented and solved by using a commercial tool [2]. Illustrative instances demonstrate that the optimization structure is able to define new operational points to the pipeline system, providing significant cost saving.
Reability Centered Maintenance (RCM), Gain and Results 3 Years After Implementation
Authors: Ribeiro Robison Tirre , Alves Pinto Nancy Flora
Published: December 2008

TBG – Transportadora Brasileira Gasoduto Boli´via Brasil S.A. — Started in 2000, a program of studies based on the methodology of Reliability Centered Maintenance (RCM) with a goal of analyzing its main and more critical facilities and systems according to this methodology seeking to guarantee a high reliability by means of the maintenance. This studies presented quite expressive results: it allowed to the participants to know in depth the systems and devices of the facilities; identify through a FMEA (Failure Modes and Effects Analysis) all the main manners of failures of the functions of the several systems and devices; to evaluate the consequences of the failures and its impact under safety’s point of view, environment and operation of the station; to determine the maintenance activities (preventive, predictive and of search of failures) necessary to the maintenance of the reliability of the station; to identify opportunities of improvements in the project of the installation seeking the increment of its reliability; to identify needs of implementation of operation procedures and maintenance or modification in the existent ones.
A Powerful Tool for Assessing Locations of Defects Missed-Out by ILI
Authors: Timashev Sviatoslav A. , Kuzmin Alexander B.
Published: December 2008

The paper describes essentials, features and possibilities of a statistical tool that permits assessing the possible location (log distance coordinate) of defects that were missed-out during inline inspection (ILI). The method is based on complete analysis of the results of the latest ILI, using the basic set of ILI tool performance metrics, introduced and substantiated by the first author. The method is based on analysis of a full set of possible outcomes of any ILI measurement, namely: true detection/non-detection; false detection/non-detection. The developed statistical tool uses combined data from the ILI tool specifications, ILI run results and verification digs. This method permits quantitative assessment of the number of falsely detected and undetected actual defects and also the distribution of their sizes for each segment of an inspected pipeline that was not verified by digs. Application of the method is described for use when deciding how many defects of different categories have been unobserved. A decision rule is described with which it is possible to be practically sure that no dangerous/reportable defects were omitted. A combined (actual and computer simulated) case of analysis of ILI and dig data accumulated for a one-kilometer long pipeline segment is presented. Using existing strength codes it is shown how to locate possible dangerous spots on pipeline segments, where additional digs or monitoring would be advised/recommended. The described method is recommended for use by pipeline companies in order to minimize the risk of leak/rupture and enhance the culture of pipeline maintenance in general.
Role of Human Factor in Pipeline Safety
Authors: Timashev Sviatoslav A. , Polouian Ludmila V. , Yurchuk Zhanna V.
Published: December 2008

The paper describes a new method of quantitative assessment of the influence of the human factor (HF) on safety and risk analysis of pipelines throughout their life cycle, based on applied theory of orgraphs (oriented graphs). The paper describes the main components, means and methods of a holistic and quantitative human reliability analysis (QHRA) using quantitative values of human error. Three types of decision making persons (DMP’s) are considered: members of maintenance/repair crews, ILI diagnosticians and different rank DMP’s that operate or own the pipeline. The applied orgraph theory is used to choose, out of a set of possible measures (the effect and cost of implementation of each of them is a known value), a subset of measures that: 1) delivers maximal decrease of the probability of pipeline disaster-type failure or 2) for a given amount of total available financial means, selects a subset of measures that maximizes the decrease of the disaster-type failure. Three real life cases are described: Choosing measures that enhance pipeline ILI results; Minimizing the third party intervention probability; Choosing security measures for an oil pipeline.
Commodity Movement Tracking (CMT): Bridging Operations and Commercial Transactions
Authors: Lewyta Michael
Published: December 2008

It is crucial to accurately track the location of commodities transported on the Embridge Pipelines Inc. (EPI) liquids pipeline. Commercial scheduling is transformed to operational need and conversely, operation need to commerce. The Commodity Movement Tracking System (CMT) integrates the movement of product with business need, tracking inventories and linking products to commercial transactions across the pipeline. CMT tracks the batches within the pipeline and provides the ability to manage and reconcile system and tank inventories. Batches are tracked from initial receipt to final delivery, incorporating information from the SCADA system and the Pipeline Scheduling system. Daily schedules are published and recorded into the CMT system as events, based on volumetric information made available through the SCADA system. In the near future, receipt and delivery events will be electronically recorded into CMT from the field flow computers. Information is processed, producing results that reflect the positioning of each batch within the system, along with an estimated time of arrival at the next station. This process incorporates the challenges of side-streaming commodities, in and out of the lines, dynamic changing of the pipeline configurations, and changes in the pipeline diameter. The modeling process involves accurate re-positioning of the batches incorporating changes within the line configuration, static pipe diameter changes, and packing and draining of the line fill resulting from pressure changes. CMT is also responsible for inventory balancing within the EPI system. Comparing the various inputs and outputs from the system to the inventory on hand provides a quick accounting balance, not only on a system-wide basis, but also on a terminal-by-terminal and tank-by-tank basis. This paper discusses the modeling process, inputs and outputs of the integrated system and future direction of managing operational needs to enhance the soundness of commercial business transactions on EPI’s liquids pipeline system.
High Pressure Pipeline Project Within a Long and Deep Tunnelling Shield in Urban Area
Authors: Maeda Ryo , Yaguchi Takehiko , Yamaguchi Hideya , Yanagi Yukichi
Published: December 2008

Installation plan of diametrical pipeline within the existing circular trunk line was officially announced in 2002 as ‘Central Trunk Line’;- gas transmission of 23.1 km length linking from the Tokyo Bay side to the opposite side of the circle. Main feature of this line is that the pipes of 610mm outside diameter, 7MPa MAOP and of Grade 552 (X80) equivalent material is to be installed within a tunneling shield all along the route to avoid unnecessary negotiation with road authorities and adjacent inhabitants. The 2m diameter tunnel will be excavated 40m under ground surface in average, 60m in the deepest. The construction started last autumn and will not be completed until the year 2009. This paper refers to be design concept and outline of the narrow and long tunnelling and piping techniques utilized to reduce the construction costs.
Fracture Toughness Testing of Pipeline Girth Welds
Authors: Shen G. , Gianetto J. A. , Bouchard R. , Bowker J. T. , Tyson W. R.
Published: December 2008

The guidelines and recommendations for fracture toughness testing of pipeline girth welds outlined in CSA Z662-03, Annex K are reviewed in this work. In Annex K of CSA Z662-03, the specimen type and notch location have been grouped into four categories and the CTOD tests are to be carried out in accordance with either BSI Standard 7448 or ASTM Standard E 1290. In the present study, CTOD tests have been conducted on a manual shielded-metal-arc weld (SMAW) that was prepared in a high strength X80 pipeline steel. The experimental results obtained by applying the two testing standards are compared. The focus was to identify the differences between these two standards that may significantly affect the test results, such as the requirements for straightness of the fatigue crack, and the equations and parameters used for evaluation of CTOD. Some additional factors affecting the testing, such as selection of test specimen location and procedures for targeting specific weldment microstructures as well as the application of local compression, are also discussed. The variation of strength and toughness with clock position around the circumference of the girth welds has also been studied.
Modified Equation to Predict Leak/Rupture Criteria for Axially Through-Wall Notched X80 and X100 Linepipes Having Higher Charpy Energy
Authors: Kawaguchi Shinobu , Hagiwara Naoto , Ohata Mitsuru , Toyoda Masao
Published: December 2008

A method of predicting the leak/rupture criteria for API 5L X80 and X100 linepipes was evaluated, based on the results of hydrostatic full-scale tests for X60, X65, X80 and X100 linepipes with an axially through-wall (TW) notch. The TW notch test results clarified the leak/rupture criteria, that is, the relationship between the initial notch lengths and the maximum hoop stresses during the TW notch tests. The obtained leak/rupture criteria were then compared to the prediction of the Charpy V-notch (CVN) absorbed energy-based equation, which has been proposed by Kiefner et al. The comparison revealed that the CVN-based equation was not applicable to the pipes having a CVN energy (Cv) greater than 130 J and flow stress greater than X65. In order to predict the leak/rupture criteria for these linepipes, the static absorbed energy for ductile cracking, (Cvs)i, was introduced as representing the fracture toughness of a pipe material. The (Cvs)i value was determined from the microscopic observation of the cut and buffed Charpy V-notch specimens after static 3-point bending tests. The CVN energy in the original CVN-based equation was replaced by an equivalent CVN energy, (Cv)eq’ which was defined as follows: (Cv)eq = 4.5 (Cvs)i. The leak/rupture criteria for the X80 and X100 linepipes with higher CVN energies were reasonably predicted by the modified equation using the (Cvs)i value.
WEPP and the Tech-Leap of Chinese Line-Pipes
Authors: Huang Kaiwen , Wang Xiaoxiang , Liu Wencheng
Published: December 2008

The WEPP in China, is the longest high-pressure pipeline in the world, eastern part of whose construction has been finished at the 1st Oct. 2003. Up to now, all the pipes of trunk line have been welded and buried under ground, about 740,000 metric tons of which were made by domestic pipe mills. Before this project the capacity of domestic pipe mills is pretty low: the max. O.D. is 711mm, the max. W.T. is 10.7mm, and the highest steel grade is API X60. However, the WEPP specification is very high: X70 with about 50% acicular ferrite, O.D. 1016mm, W.T. 14.6/17.5/21.0/26.2mm, and more than 190 J CVN value under −15 . This kind of pipe has never been made before in China. However, within about 2 years, Chinese mills successfully fulfilled the development and manufacturing of X70 steel coils and plates, the technical reconstruction of old production lines and installation of the new ones, the scientific research of pipe forming and high speed welding technology and test method, and the technology development of procedure and facilities for inside flow coating and outside 3PE coating. All the above will be detailed in this paper.
A Risk Assessment Model for Pipelines Exposed to Geohazards
Authors: Esford Fiona , Porter Michael , Savigny K. Wayne , Muhlbauer W. Kent , Dunlop Colin
Published: December 2008

Transredes S.A. currently operates over 5,500 km of natural gas and liquids pipelines throughout Bolivia. These traverse geologically active terrain, subject to earthquakes, floods and landslides. Construction of these pipelines dates as far back as 1955, with some currently operating under conditions not foreseen at design. A quantitative risk assessment procedure was developed to rank the threats to the pipelines and target locations exposed to the highest level of risk. The objective was to implement a systematic means of prioritizing capital and maintenance activities based on risk management principles. The procedure was implemented on the OSSA-1 pipeline as part of a pilot study. This paper describes the OSSA-1 Pilot Project, with emphasis on how risk assessment procedures were customized to address the pipeline’s elevated exposure to ‘geohazards’.
Construction and Installation of X100 Pipelines
Authors: Glover Alan , Horsley David , Dorling David , Takehara Junichiro
Published: December 2008

The developments of gas fields are increasingly occurring in more remote locations and further from the prime gas demands. Pipeline activity continues to focus on arctic regions of both Canada and the United States. Cost effective solutions to these challenges can be found through innovative technology and the use of higher pressure and higher strength pipelines. TransCanada and its partners have been involved in a series of technology programs on high strength steels, particularly X100, that are focussed on its application for high pressure long distance pipelines. In order to evaluate this technology two field installations of X100 have been performed on the TransCanada system within Alberta. These installations have evaluated the summer and winter construction aspects of X100 pipelines. This paper will describe the work performed to enable the two projects to occur, and the results of the installation. The summer project occurred on the Westpath loop, and consisted of 1 km of NPS 48 by 14.3 mm X100 and was installed in September 2002. The winter project was on the Godin Lake Loop and consisted of 2 km of NPS 36 by 13.2 mm X100 and will be installed in February 2004. The paper will describe the approach taken to the pipe development and the properties required, the requirements for a strain-based design, the fracture control plan, and the welding requirements. Discussion will cover the installations and construction and the conclusions in terms of future projects. The role of code and regulatory bodies in the successful implementation will be covered.