bluuebunny/crossref_metadata_2025 huggingface dataset:
The Development of X80 Steel Plate and Coil for the 2nd West-East Pipeline Project
Authors: Yin Yuqun , Huang Yixin , Yao Yongkuan , Wang Daoyuan , Wu Yonglong , Stalheim Douglas G.
Published: July 2009

The growing economy of China has resulted in an increase in energy demands. This increased demand for energy has resulted in plans to expand the oil and gas transmission pipeline infrastructure throughout China. This transmission pipeline infrastructure expansion demands higher strength steels of API grade X70 and X80 for economical movement of the oil and gas. With most of the major natural gas supply in countries to the west of China and the major population centers of China in the east, long distant transmission pipelines from west to east have been built with additional capacity being designed. The first major natural gas transmission pipeline, 1st West-East Pipeline was API X70. A parallel mainline of approximately 4950 km with 8 sub lines resulting in an overall total length of approximately 8800 km is being designed for construction in 2008. This line will be the 2nd West-East Pipeline Project and will be built out of API X80. The major dimension of this line is 1219 mm OD × 18.4 mm wall thickness. Nanjing Iron and Steel Company (NISCO) in Nanjing, China commissioned a wide plate/coil Steckel mill in 2004 and has successfully developed API grades in plate and coil for the Chinese pipeline industry. Since 2004 NISCO has successfully ramped up production to where in 2007 anticipated delivery of API plate and coil will be approximately 350,000 mT. Over that time period NISCO has been developing API X80 plate and coil capabilities in anticipation of the 2nd West-East Pipeline Project. The 2nd West-East Pipeline specification major requirements for coil and plate mechanical properties include round bar tensile testing, YT maximum of 0.93 for round bar, ≥ 240 J @ −20 °C average TCVN and ≥ 85% DWTT shear average @ −15 °C. During the development process two alloy approaches have been identified for plate and coil to produce the ferrite/acicular ferrite microstructure required for API X80 pipe. This paper will describe Nanjing Iron and Steel Company’s development and results to produce API grade X80 plate and coil that successfully met the specification requirements of the 2nd West-East Pipeline Project.
Improved DWTT Performance on Heavy Gauge API Plate and Coil From 150 and 180 mm Thickness Slab at Nanjing Iron and Steel Company, Nanjing China
Authors: Yin Yuqun , Huang Yixin , Yao Yongkuan , Wang Daoyuan , Wu Yonglong , Stalheim Douglas G.
Published: July 2009

Economical movement of energy through densely populated regions of China to support economic growth has resulted in typical natural gas transmission pipeline designs of API grade X70 that utilize wall thicknesses in a range between 17 and 32 mm and OD at 1016 mm. The DWTT requirement for many of the specifications is ≥ 85% shear average at −10 °C to −15 °C in the plate or coil. Achievement of good fracture toughness, such as DWTT is heavily related to the total reduction from slab thickness to finish plate thickness. Ideally a total slab to finish plate thickness reduction in excess of 12:1 or at a minimum 10:1 is desirable to properly condition the austenite grains for good DWTT performance. Many of the Chinese steel producers, including Nanjing Iron and Steel Company (NISCO) have slab thicknesses less than 250 mm with several less than 200 mm, especially in wider widths to support the 1016 mm OD. This results in total slab to finish plate thickness reductions less than 10:1 and in some designs total reductions down to 7:1. This challenges the steel producer of plate or coil in achieving the required specification average DWTT percent shear on a consistent basis. For heavy gauge plate and coil in the widths required for the Chinese pipeline industry NISCO typically uses a 150 mm slab or a 180 mm slab. NISCO has to routinely use slab to finish plate or coil thickness total reductions less than 10:1. This paper will describe NISCO’s successful development related to production of heavy gauge API X70/X80 grade plate and coil meeting the DWTT percent shear requirement in China utilizing slabs that result in total slab to finish plate/coil reductions of less than 10:1.
Development of X100 Linepipe Steel With High Deformation Capacity
Authors: Seo Dong-Han , Yoo Jang-Yong , Song Woo-Hyun , Kang Ki-Bong
Published: July 2009

Recent linepipe steel is required to have enough deformation capacity through longitudinal direction at severe environments such as permafrost or seismic region, even though after anti-corrosion coating treatment in pipe. Under this background, the development of X100 linepipe steels with high strain aging resistance was tried. As a basic study, the effects of aging temperature, pre-strain and specimen dimension on the strain aging of pipes were carefully studied. It was found that strain aging behavior of plate and pipe was different in through thickness direction and specimen position along circumference. Several experimental trials with lots of process variables have been performed to enhance the strain aging resistance of X100 linepipe steels. By changing chemical composition and rolling / cooling condition, X100 plate steel was newly produced for achieving the high deformation capacity. X100 pipes with 1m length were manufactured by using UOE simulator which can do U-ing, O-ing and expansion at the same machine. After pipe forming, coating simulation to evaluate strain aging characteristics of pipes was performed by with small specimen. The yielding behaviors were examined after aging treatment for coating simulation.
Investigating the Relative Severity of Dents in Pipelines Based on Magnetic Flux Leakage Inspection Data
Authors: Tindall Leanne M. , Race Julia M. , Dawson Jane
Published: July 2009

Dent damage in pipelines may result from either impact damage caused by third parties or construction damage. Third party damage generally occurs on the upper half of the pipe (between the 8 o’clock and 4 o’clock positions) and has historically contributed to the highest number of pipeline failures. Dents caused during construction generally occur on the bottom half of the pipe and tend to be constrained by the indenter causing the dent, i.e. a stone or rock in the pipeline bed/backfill. However, all dents have the potential to cause an increase in stress in the pipeline, and consequently increase the pipeline sensitivity to both static and fatigue loading. Although there are extensive recommendations for the ranking and repair of dents, recently, failures of dents that are acceptable to pipeline codes have been reported. Guidance is therefore needed in order that operators can identify dents for which excavation and inspection is uneconomic and could potentially be damaging to pipeline safety and dents for which further action is required. This paper provides a review of the published recommendations for the treatment of pipeline dents and goes on to present a method that is being developed to determine the relative severity of dents in a pipeline using magnetic flux leakage (MFL) signal data. The proposed method involves measuring MFL signal parameters related to the geometry of the dent and relating these to high resolution caliper inspection data. This analysis enables a relationship to be established between the MFL signal data and dent depth and shape measurements. Once the model is verified, this analysis can then be used to provide a severity ranking for dents on pipelines where only MFL data is available.
A Fiber Bragg Grating Sensing System and Its Application to Monitoring Landslides and Associated Pipelines
Authors: Chen Pengchao , Liu Jianping , Hao Jianbin , Jing Hongyuan , Zhao Jianchun
Published: July 2009

The integrity of oil and gas pipelines is seriously threatened by landslides and other geohazards in tough terrain in western China. Monitoring the landslides with slow, continual movements and the strain build up in pipelines due to landslides is an effective way to maintain the serviceability of pipelines. In this paper, a monitoring system based on Fiber Bragg Grating (FBG) sensors is developed and applied. The system is made up of four related parts: the pipeline strain measurement of the with FBG strain sensors, the soil-pipeline contact pressure detecting with FBG soil pressure cells, the landslide inner deformation monitoring with pipe strain gages and the landslide surface monitoring with a special buried concrete beam with FBG sensors. The system is used to monitor a huge, slow moving landslide and the pipeline affected by it. The monitoring results are analyzed and the pipeline integrity is assessed basing the monitoring results. The FBG system has been proved to be suitable to monitor landslides and pipelines automatically and real-timely.
The Experimental Study and Real Time Forcast-Control Method of the Severe Slug Flow in Offshore Production Riser
Authors: Li Qingping , Guo Liejin , Yao Haiyuan , Wang Xin
Published: July 2009

With the development of the offshore oil and gas fields, multiphase transportation technology is becoming more and more important because it’s a cost-effective way for marginal and offshore fields. However, the complexity characteristics of the gas-oil-water multiphase flow, the hard offshore environmental conditions bring huge challenges to offshore platforms, subsea production systems, subsea pipelines and risers. Severe slugs in offshore risers, hydrate and wax block in subsea pipelines and flowlines will appear when the production system is shut down. In this paper, an experimental facility to simulate the riser slug flow is built, and the flow pattern of severe slug is given, the effects of the incline angles and viscosities on the formation of severe slugs in the riser is experimentally studied and analyzed using water-air, oil-air and water-oil and air. On this base, a cost effective real-time recognition technology of severe slug in the riser is present and its related automatic throttle control method has been validated by natural gas and crude oil with the 25m high riser system, which devotes to the future deepwater riser slug control system.
Development and Application of Pipeline Integrity Management System
Authors: Wang Xiaolin , Shuai Jian , Zuo Shangzhi
Published: July 2009

As an effect way to guarantee pipeline safety, pipeline integrity management (PIM) has been paid great attention in oil-gas pipeline industry. In this paper, a pipeline integrity assessment and management software (PIAMS) has been developed to make pipeline integrity management technique to be applied conveniently. PIAMS has been developed with four main modules: database management (DM), anticorrosion system evaluation (ASE), corroded defects evaluation (CDE), and risk assessment (RA). In ASE module, classification evaluation is used to evaluate coating integrity with holiday density, attenuation of inspection current and insulated resistivity coefficient, as well as cathodic protection efficiency with on/off potential in volts. In CDE module, three methods recommended respectively by ASME B31G-91, DNV RP-F101 and PCORRC are used to evaluate residual strength of corroded pipeline. Being the core of PIAMS, RA plays a crucial role in integrity management. According to significant characteristics, pipeline is sectioned into segments, each of which should be assessed with scoring system recommended by Pipeline Risk Management Manual. This paper describes the framework, database, functions and application of PIAMS.
Instrumentation Improvements for the Leak Detection and Batch Tracking Systems of the Sa˜o Paulo Brasi´lia Pipeline (OSBRA)
Authors: de Almeida Ma´rcio Manha˜es Gomes , Morais de Andrade Jose Augusto , Kotchetkoff Neto Andre Paulo
Published: July 2009

OSBRA is the 964 Km pipeline which supplies over 6.500.000 m3/year of gasoline, diesel oil and LPG to the Brazilian Midwestern region. Products on OSBRA pipeline are pumped 24 hours a day and 365 days a year on a scheduled basis from Planalto Paulista Refinery – REPLAN to 5 midsize cities through 6 remote operated pumping stations located along the pipeline. The pipeline operation, including pumping and valve actuations and tank farm monitoring, is done remotely from PETROBRAS Transporte S/A – TRANSPETRO National Pipeline Control Center (CNCO). A real time leak detection system (LDS) was supplied and installed at the CNCO. The LDS is based on measurements of flow and pressure as well as pump and valve status along the pipeline. An actual field leak test was done in order to validate and verify the LDS performance. The LDS performance was considered satisfactory at the first time, but after a few months an excessive number of false leak alarms started to occur. A detailed investigation was conducted both on operational procedures and field instrument installation. This report shows how this investigation was conducted and the main recommendations that were agreed in order to avoid the LDS to detract from credibility and the creation of complacency. It is presented the existing limitations on the flow measurements and the improvements that are planned to field instrumentation, operational/maintenance procedures and the OSBRA LDS and Batch Tracking models so it could reach a higher performance level.
Ground Movement Monitoring of Unstable Pipeline Corridors With Fiber Optic Slope Indicators
Authors: McClarty Edward
Published: July 2009

Spectra Energy Transmission (SET) owns and operates approximately 6,000 kms of raw and sweet natural gas transmission pipelines in northeastern British Columbia and northwestern Alberta. This geographic area is very susceptible to landslides and unstable land mass due principally to the local geological regime. These slope instabilities present long term operational challenges to pipeline companies. Geotechnical pipeline failures are not uncommon and pipeline operators spend significant portions of their operational budgets on geotechnical issues. SET has developed a geotechnical integrity program to take a proactive approach to these geotechnical issues. Ground movement monitoring is a significant component of this integrity program and provides physical data that becomes the backbone of remedial works. SET currently utilizes traditional slope indicators, surface survey monitoring, differential GPS, LiDar and InSar technologies to obtain this ground movement data. As an element of the geotechnical integrity program, SET utilizes fiber optic sensors to monitor the pipeline’s reaction to ground movement. After the initial installation of these fiber optic sensors, it was apparent that they could be bonded to almost any structural member. Potential to use the fiber optic sensors to extend the life of a traditional slope indicator was discussed with the sensor manufacturer and six joints of slope indicator casing were fitted with fiber optic sensors. These instrumented joints were then installed across known slide surfaces at various existing monitoring locations. Periodic data collection of both the slope indicator and the fiber optic sensors allowed for ground movement correlation up to the shearing of the slope indicator. It is anticipated that with proper installation and further design improvements from the manufacturer that the fiber optic instrumented slope inclinometers will facilitate ground movement monitoring beyond the life of the traditional slope indicator. This paper discusses the results of the initial trial, what was successful, what lessons were learned, and which pipeline scenarios would benefit from this technology and potential methodologies to monitor ground movement and pipeline bending concurrently.
Detection and Localization of Micro-Leakages Using Distributed Fiber Optic Sensing
Authors: Inaudi Daniele , Belli Riccardo , Walder Roberto
Published: July 2009

Distributed fiber optic sensing offers the ability to measure temperatures and strain at thousands of points along a single fiber. This is particularly interesting for the monitoring of pipelines, where it allows the detection and localization of leakages of much smaller volume than conventional mass balance techniques. Fiber optic sensing systems are used to detect and localize leakages in liquid, gas and multiphase pipelines, allowing the monitoring of hundreds of kilometers of pipeline with a single instrument and the localization of the leakage with a precision of 1 or 2 meters. This contribution presents recent testing results on controlled field trials. The tests demonstrate that it is possible to reliably detect oil leakages of the order of 10 liters to 1’000 liters per hour, corresponding to 0.01% to 0.1% of the pipeline flow. Tests were performed with small temperature differences between liquid and ground. The detection time was between 1 minute and 90 minutes. All simulated leakages were detected and localized to better than 2m accuracy. The paper describes the main parameters that affect the response time and detection volume, including the relative position of the leak to the sensing cable, temperature contrast and instrument performance. We also briefly report on relevant full-scale installations for the permanent monitoring of oil, brine and natural gas pipelines.
Transportation of Waxy Crudes in Batch Through China West Crude Oil Pipeline With Pour-Point-Depressant Beneficiation
Authors: Ling Xiao , Zhang Jinjun , Li Hongying , Huang Qiyu , Hou Lei
Published: July 2009

The West Crude Oil Pipeline, 1500km long, a newly constructed pipeline, was put into operation in August 2007. Several crudes with different wax content and thus different pour point/gel point are pumped through the pipeline in batch, with the gel point ranging from −10°C to 10°C. In winter, the lowest ground temperature will be as low as 2°C at the depth where the pipeline is buried. The pour-point-depressant (PPD) was used to reduce gel point of the waxy crudes to ensure safety of pipeline operation. To make sure that the selected PPD reduce gel point effectively, field tests were conducted from September to November in 2007 to prepare for winter operation. The PPD was injected to the waxy crudes at the initial station, and gel points and densities were measured at the initial station and several intermediate stations along the pipeline. The test results show that the PPD may effectively reduce the gel point of the crude, but the effectiveness depends on the composition of crude oil; the reduced gel point of the crude may recover during pipelining; reheating temperature at the intermediate stations may seriously affect the flow properties of the PPD beneficiated crude. Reheating the PPD beneficiated Tuha crude oil to the temperature range of 20 ∼ 35°C results in poor flow properties. This indicates that the reheating temperature at the intermediate stations must be properly controlled to avoid falling into this temperature range. Based on this field test, the pipeline was safely operated for last winter.
Recent Developments of High Strength Linepipe Steels on Coil
Authors: Liebeherr M. , Ruiz Romera D. , Soenen B. , Ehlers S. , Hivert E.
Published: July 2009

The present paper deals with the recent steel development for linepipe applications at ArcelorMittal. With the recent upgrade of the downcoiler capabilities in three European steel plants it is now possible to supply hot rolled coils in width up to 2150mm for the economical production of X70 large diameter, spiral welded transmission trunk lines with 25.4mm wall thickness. In view of the increased dimensional feasibility range a couple of new product development projects had been launched. Two of these products with very demanding application properties are already being industrialized. It concerns respectively X70 in 22mm thickness with improved low temperature BDWTT properties (85% shear area at −10°C) and X80 in 16mm, likewise with low temperature BDWTT properties and, additionally, with low Y/T ratio. The first pre-series deliveries have been successfully transformed to pipes in one of our client’s spiral welded pipe mill. Another product development project which is still in the conception phase concerns the development of X100 in thickness up to 12.7mm. The actual progress of the mentioned projects will be documented here. Key for the realization of such demanding products is a precise control of the final microstructure. This is in particular true for high strength steels with improved toughness. Therefore, a lot of research efforts were spent in order to understand the link between microstructures and properties. Our current understanding will be detailed in this paper.
Contribution to the Evaluation of VIV Analyses Using Wake Oscillator and Vortex Tracking Models
Authors: Carneiro Daniel Lyrio , Ellwanger Gilberto Bruno , Galgoul Nelson Szilard
Published: July 2009

Fatigue due to vortex-induced vibrations (VIV) is one of the major uncertainties today in the design of slender offshore structures, such as risers, pipelines, umbilicals, tendons and mooring lines, required for oil and gas production in deep waters. The absence of reliable tools for quantitative analyses of this phenomenon is a technological barrier, which is being faced by several research groups. This paper presents valuable VIV results achieved by the author, using “wake oscillator” and “vortex tracking” models, when researching for his M. Sc. dissertation. Time domain analyses were performed using a commercial software. First results describe the response of the evaluated models for two degrees-of-freedom rigid cylinders by tracing lateral displacement versus flow velocity curves. These curves are plotted over others previously published in recognized recommended practices, articles and theses. Afterwards, VIV analyses results for a steel catenary 10-inch diameter riser in three-dimensional current profiles were compared to measured values. The considered riser, installed in 910m water depth offshore Brazil, is possibly the only monitored SCR with no VIV suppression devices in the world today. The results were considered satisfactory, despite some discrepancies: the model which appeared to be one of the most attractive for the rigid cylinder case, failed to predict VIV in the SCR under an irregular current profile, for example. Vortex tracking models presented excessive low frequency response in the SCR analyses. Authors believe that this response is unrealistic, and these frequencies can be dissipated by using a more adequate damping model than that employed by the utilized program.
Numerical Simulation of the “Floating Spiral” Pipeline Installation Procedure: Second Stage, Spiral Transportation, Behavior Under Waves
Authors: Jacovazzo Bruno Martins , Correˆa Fabri´cio Nogueira , Albrecht Carl Horst , Jacob Breno Pinheiro , Torres Fernando Gomes da Silva , de Medeiros Antonio Roberto
Published: July 2009

The Floating Spiral pipeline installation method consists basically in winding the pipeline into a huge floating spiral, and towing this assembly to the installation site, where the spiral is then unwound and lowered to the seabed. In this method the pipeline is fabricated onshore, as the spiral is created, under well controlled conditions and relatively relaxed time constraints. Therefore the welds can be better inspected, which allows for optimal control of quality in pipeline manufacturing. The first stage of the installation process by this method consists in setting the pipeline afloat and winding it elastically to form a large flat spiral. This stage is studied in a companion paper [1], to be also presented at IPC2008. The second stage consists in towing the floating spiral pipeline employing standard tugboats before laying it at the installation site. The objective of this work is, therefore, to present results of parametric studies for a large length pipeline at this second stage of the Floating Spiral method. The focus now is in the pipeline behavior under wave environmental conditions during transportation. Several numerical simulations are performed and the results are discussed and compared.
Advanced Engineering Critical Assessments of Seam Weld Features in Pressure Cycled Hazardous Liquid Pipelines
Authors: Spencer Kevin , Santamaria Wilson , Dawson Jane , Lu Hong
Published: July 2009

The performance of older ERW pipelines has raised concerns regarding their ability to reliably transport product to market. Low toughness or “dirty” steels combined with time dependent threats such as surface breaking defects, selective corrosion and hook cracks are especially of concern in hazardous liquid pipelines that are inevitably subject to cyclic loading, increasing both the probability and rate of crack growth. The existing methods of evaluating seam weld flaws by hydrostatically testing the pipeline or In-Line Inspection (ILI) with an appropriate technology are well established. Hydrostatic testing, whilst providing a quantified level of safety is often impracticable due to associated costs, logistics and the possibility of multiple failures during the test. ILI technologies have become more sophisticated and as a result can accurately detect and size both critical and sub-critical flaws within the pipeline. However, the vast amounts of data generated can often be daunting for a pipeline operator especially when tool tolerances and future growth are required to be accounted for. For either method, extensive knowledge of the benefits and disadvantages are required to assess which is the more appropriate for a particular pipeline segment. This paper will describe advances in the interpretation of seam weld flaws detected by ILI and how they can be applied to an Integrity Management Plan. Signal processing improvements, validated by in-field verifications have enabled detailed profiles of surface breaking defects at seam welds for ERW pipelines to be determined. Using these profiles along with established fracture and fatigue analysis methods allows for reductions in the unnecessary conservatism previously associated with the assessment of seam weld flaws detected by ILI. Combining these results with other available data, e.g. dig verifications, previous hydrostatic testing records, enables more realistic and better-informed integrity and maintenance planning decisions to be made. A real case study conducted in association with a pipeline operator is detailed in the paper and quantifies the benefits that can be realised by using these advanced assessment techniques, to safely and economically manage their assets going forward.
Integrity of Old Pipelines Buried in Petroleum Products Storage Terminals
Authors: Fujikawa Mauro Y. , de A. Silva Eduardo O. , A. das Neves Reinaldo , Massitelli Derci Donizeti , Abraha˜o Newton Orlando , Schraml Karina C.
Published: July 2009

This work aims to present the results obtained from the experience gained through the accomplishment of the inspection with the ultrasonic umbilical pig in a non-piggable internal pipe buried in the Transpetro Storage Terminal in Sa˜o Caetano do Sul, in Sa˜o Paulo, Brazil. The pipeline considered in this work is a line for marine fuel oil, which, because of its high viscosity, must be heated in order to flow. The oil is heated in the terminal by the steam produced in boilers. The heat transfer may occur in a heat exchanger or inside the storage tank, and the pipeline referred is thermally isolated. So that the line could be inspected, it was divided in two parts, one upstream of the pumps (suction), which is a 12-inch line, and the other downstream of the same pumps (discharge), which is a 14-inch line. This work has been developed by Transpetro’s Pipeline Operation, Maintenance, Inspection and Safety Departments together, since the planning phase, passing by the job execution and getting to the conclusion. To begin with, the operational liberation of the line had to be agreed between all the departments involved with the PIG inspection, which were mentioned before, and Transpetro’s Logistics Department. Once the PIG passage was scheduled, an initial cleaning had to be performed by the Operation Activity. Since this line is non-piggable, the installation of adaptations was necessary. After that, the passage of cleaning PIGs was possible, and the line sections could be enabled. The next step was the inspection of the pipeline with umbilical ultrasonic PIGs. After the passage of these PIGs, the adaptations had to be removed and the pipeline had to be conditioned for the operational return. After this part of the inspection was finished, the verification of the results issued was necessary. Once the theoretical results were available, ditches were opened for correlation inspection and temporary repairs in the most critical points for the operation were applied. The last part of the work consists in an analysis study of technical and economical viability for rehabilitation of the lines.
Transfers of Ownership: The Devil Is in the Details
Authors: Palmer Ken , Byrd W. R.
Published: July 2009

During the lifespan of a pipeline, it will most likely undergo several generations of acquisition, divestiture and other company transitions. This poster session commences with an overview of what is involved in a company name change. The reader is then taken through a detailed presentation of the steps required for name change completion. Topics covered in this progression include: inventorying, agencies to contact, company personnel to be interviewed, forms to complete, required fees, required signatures and report preparation. Methodology is presented in a strategically designed format that allows one to complete this process in a timely and efficient manner. Information in this presentation will make one realize that a name change goes far beyond the relettering of company signs.
Finite Element Modelling of Volumetric and Shear Ductile Micro- and Macro-Fracture Processes Under Long Time Loading
Authors: Pajic Lucija , Lukyanov Alexander A.
Published: July 2009

Submarine and onshore pipelines transport enormous quantities of oil and gas vital to the economies of virtually all nations. Any failure to ensure safe and continuous operation of these pipelines can have serious economic implications, damage the environment and cause fatalities. A prerequisite to safe pipeline operation is to ensure their structural integrity to a high level of reliability throughout their operational lives. This integrity may be threatened by volumetric and shear ductile micro- and macro-fracture processes under long time loading or continuous operation. In this paper a mathematically consistent damage model for predicting the damage in pipeline structures under tensile and shear loading is considered. A detailed study of widely used damage models (e.g., Lemaitre’s and Gurson’s models) has been published in the literature. It has been shown that Gurson’s damage model is not able to adequately predict fracture propagation path under shear loading, whereas Lemaitre’s damage model (Lemaitre, 1985) shows good results in this case (e.g., Hambli 2001, Mkaddem et al. 2004). The opposite effect can be observed for some materials by using Gurson’s damage model in the case of tensile loading (e.g., Tvergaard and Needleman 1984; Zhang et al. 2000; Chen and Lambert 2003; Mashayekhi et al. 2007) and wiping die bending process (Mkaddem et al. 2004). Therefore, the mathematically consistent damage model which takes into account the advantages of both Lemaitre’s and Gurson’s models has been developed. The model is based on the assumption that the damage state of materials can be described by a damage tensor ωij. This allows for definition of two scalars that are ω = ωkk/3 (the volume damage) (Lukyanov, 2004) and α = ωij′ωij′ (a norm of the damage tensor deviator ωij′ = ωij −ωδij) (Lukyanov, 2004). The ω parameter describes the accumulation of micro-pore type damage (which may disappear under compression) and the parameter α describes the shear damage. The proposed damage model has been implemented into the finite element code ABAQUS by specifying the user material routine (UMAT). Based on experimental research which has been published by Lemaitre (1985), the proposed isotropic elastoplastic damage model is validated. The results for X-70 pipeline steel are also presented, discussed and future studies are outlined.
The Performance of Drag Reducing Agents in Multiphase Flow Conditions at High Pressure: Positive and Negative Effects
Authors: More´ Parimal P. , Kang Cheolho , Oliveira Magalha˜es Alvaro Augusto
Published: July 2009

Drag reducing agents (DRA) in multiphase flow pipeline is of great interest in petroleum and pipeline industries since production can be increased by decreasing the pressure drop. Experiments were carried out in a 36-m long, 10-cm diameter multiphase flow system to examine the effect of drag reducing agents (DRA) on average pressure drop and slug characteristics. Superficial liquid velocities between 0.5 and 1.5 m/s and superficial gas velocities between 4 and 10 m/s were investigated. Temperature and pressure were maintained at 30 °C and 0.45 MPa. The DRA concentrations of 0, 25 and 50 ppm were used in this study. The results show that the average pressure drop decreased significantly by the change of flow characteristics when DRA was injected into the pipeline. At certain conditions, it was seen that a transition in flow pattern occurred from slug to wavy stratified flow with DRA. In addition, DRA was able to decrease the degree of turbulence at the gas-liquid interface with the addition of DRA. Some negative performance with the use of DRA in multiphase flow pipeline is also presented in this paper.
Pipeline Integrity Excavation Challenge in a High Consequence Area
Authors: Richardson Joseph J. , Kolbuck Vincent P.
Published: July 2009

A portion of Enbridge Pipelines 30 inch crude oil/NGL pipeline runs from Bay City, Michigan to Sarnia, Ontario. A geometry tool found a topside dent indication and GPS data indicated that the dent was located in the Saginaw River which is considered Coast-guard navigable. This pipe segment is located within a defined high consequence area making Pipeline and Hazardous Materials Safety Administration (PHMSA) timing applicable. On top of the normal problems associated with digging in a river, the riverbed soil was known to contain dioxin contamination related to its industrial history. This paper provides an overview of the practical problems encountered in completing this dig. Governmental construction permitting proved to be the most difficult aspect of the work. Contaminated soils caused Enbridge to hire a specialized water handling company. Significant engineering challenges included design and installation of a 100 × 50 foot coffer dam with 70 foot long sheets. The coffer dam design required a flood plain erosion study. After many months of permitting process, all required permits were obtained and construction was started. The construction included three major elements, water handling, coffer dam installation and excavation of the suspected defect. After 2 months of work to uncover the suspected dent, it was located and analyzed. The dent did not meet Enbridge repair criteria, but mechanical reinforcement was installed as a precaution. Final steps included backfilling and coffer dam removal. From start to finish the construction portion of the dig took about 5 months to complete.
Effects of Specimen Geometry on Fatigue-Crack Growth Rates in Pipeline Steels
Authors: Treinen J. M. , Darcis Ph. P. , McColskey J. D. , Smith R. , Merritt J.
Published: July 2009

The effects of specimen geometry on the fatigue crack growth rates (FCGR) in API X65 and X100 pipeline steels were explored by use of the middle tension and compact tension specimen geometries. It was found that the specimen type has little influence on the stage II linear fatigue crack growth region for these steels. Furthermore, the FCGR behavior in the longitudinal and transverse directions was found to be nearly identical for both steels. Also of interest was a comparison of the FCGR results to the BS 7910 design curves, which showed a discrepancy between the results and the standard only at low delta K levels. A finite element analysis of the compliance relationships used to predict the crack lengths during testing of both specimen types revealed that the expression for both the middle tension specimen and the compact tension specimen were found to be valid. Although the curved geometry of the middle tension specimen caused slightly different compliance results, these differences did not appear to affect the FCGR results.
Electric Resistance Welded Seam Inspection Using Circumferential Flux
Authors: Nikolova Natalia K. , Cronin Duane , Pasha Sabir M. , Amineh Reza K. , Smith Ian , Thompson Ron , Hare James R.
Published: July 2009

For conventional magnetic flux leakage (MFL) inspection where an excitation magnetic field is generated in the axial direction of a pipeline, axially oriented crack detection is impossible [1][2]. A new MFL tool design is presented that creates an excitation field in the circumferential or transverse direction, allowing for axial crack detection, as well as the more conventional metal loss detection. Design criteria that ensure detection include sufficient sensor density and magnetic field uniformity at sensor locations. The result is a new type of circumferential MFL inspection tool that can not only detect corrosion and other metal losses, but also axially oriented cracks. Based on the results of a series of inspection runs 22 crack-like features in the electric resistance weld (ERW) were investigated with 19 of those being verified as linear long seam features and were subsequently permanently repaired. Further information on the efficacy of this design is clarified in [2].
Obtaining Corrosion Growth Rates From Repeat In-Line Inspection Runs and Dealing With the Measurement Uncertainties
Authors: Nessim Maher , Dawson Jane , Mora Rafael , Hassanein Sherif
Published: July 2009

The ability to accurately determine the rate of corrosion growth along a pipeline is an essential input into a number of key integrity management decisions. For example, corrosion rates are needed to predict pipeline reliability (probability of failure and/or probability of exceedance) as a function of time, to identify the need for and timing of field investigations and/or repairs and to determine optimum re-inspection intervals to name just a few applications. As more and more pipelines are now being inspected using intelligent in-line inspection (ILI) tools for a second or even third or fourth time, pipeline operators require reliable guidelines for comparing repeat ILI data sets to obtain valid corrosion growth rates. Because of the measurement uncertainties associated with corrosion size estimated from a single ILI run, the corrosion growth rate calculated from consecutive ILI runs has a degree of uncertainty that needs to be considered in determining valid and accurate corrosion growth rates. The ratio between the measured corrosion growth and the measurement error is an important parameter in determining a meaningful distribution of the corrosion growth rate either when performing defect to defect comparisons or when comparing the defect populations in pipeline segments. When this ratio is small the associated uncertainty can be too large to make meaningful probabilistic inferences. As the ratio increases, the effect of measurement uncertainty becomes more manageable, allowing growth rate distributions to be calculated with reasonable confidence. This paper describes an approach to define the probability distribution of corrosion growth rates as a function of a simple parameter that characterizes the ratio between the ILI-observed corrosion growth and the ILI measurement error. This approach has been developed as part of an ongoing PRCI-sponsored research project to produce procedures for determining and validating corrosion growth rates from repeat ILI runs. The paper also provides examples using sample data from repeat ILI runs showing the application of these procedures, the treatment of measurement uncertainty, the resulting corrosion growth rate information that can be obtained and the associated level of confidence in the results.
Uncertainty Evaluation of the Natural Gas Molar Mass and Its Flow Rate Impact
Authors: de Oliveira Elcio Cruz
Published: July 2009

In Brazil, the National Oil Agency — ANP and the National Metrology Institute elaborated Regulation No 1, on June 19th 2000. This government decree approves the Regulation of the Measurement Technique of Oil and Natural Gas, which establishes the minimum conditions and requirements for the oil and natural gas measurement systems, in order to guarantee accurate and complete results. The natural gas measurement fiscal systems must be projected, calibrated and operated so that the measurement uncertainty does not exceed 1.5%. Based on the norms AGA and ISO, the mathematical model for the calculation of the mass flow rate, depends on quantities that have well known uncertainty such as: orifice plate diameter, pipeline internal diameter, compressibility factor, discharge coefficient, differential pressure, static pressure and flow temperature. However, for the molar mass standard uncertainty fixed values are utilized in Brazil (mainly by IPT and PUC-RJ), around 0.30%, independent of the natural gas composition. The objective of this work is to develop a methodology to calculate the molar mass uncertainty of the natural gas derived from its chemical composition, analyzed by gaseous chromatography and to comparing it with the value currently practiced, evaluating the impact proceeding from this difference in the mass flow rate of the natural gas. Based on this methodology, the molar mass uncertainty is around 0.05% and the fiscal system uncertainty decreases in more than 10% when it is compared with the mass molar fixed value uncertainty.
Development of a GIS Database of Corrosion Hazards for Use in Pipeline Integrity Assessments
Authors: Slayter David L. , Hitchcock Christopher S.
Published: July 2009

Geologic hazards pose a significant threat to pipeline integrity. As an existing pipeline system ages, targeted analysis and positioning of maintenance resources become increasingly important to remediating problem pipeline sections and to ensure timely response to system failures. A geographic information system (GIS) now is commonly used to model pipeline systems. Significant geologic hazards can be mapped and effectively managed in a GIS database as a way to assess risk and to target pipeline remediation resources. In particular, the potential for soil corrosion is a significant threat to pipelines. In the U.S., digital soil maps from the United States Department of Agriculture, Natural Resources Conservation Service (USDA NRCS) have been compiled into the Soil Survey Geographic (SSURGO) database. Numerous soil attributes are stored in the database allowing for a detailed examination of soil characteristics. SSURGO data is largely consistent in quality and geographic extent across the U.S. and is the best available database for a national assessment of soil corrosion potential. We describe the development of a national database for the collection of locations of known corrosion from pipeline system managers. This database can be compared to soil conditions, as noted in SSURGO or other supporting soil data, for the development of a model of soil parameters that may indicate the future potential for buried pipeline corrosion. This paper outlines the need for such a database, significant design considerations and the proposed process for model development.
A Simplified Model for Evaluating Strain Demand in a Pipeline Subjected to Longitudinal Ground Movement
Authors: Yoosef-Ghodsi Nader , Zhou Joe , Murray D. W.
Published: July 2009

A simplified model was developed to calculate the maximum tensile and compressive strains due to a uniform movement of a block of soil in a direction parallel to the pipe axis using a closed-form solution of the governing differential equations. The model employs the theory of plasticity for modelling the pipe material based on normality plastic flow rule, the von Mises yield criterion, and isotropic strain hardening. While the pipe was assumed to have a bilinear, stress-strain curve with strain hardening, the pipe-soil friction was assumed to have an elastic-perfectly plastic force-deformation response. The model accounts for the initial thermal axial strains in the pipe and biaxial state of stress in the pipe due to internal pressure. The model is capable of accommodating pipe bends at the ends of the sliding zone. The relationship between the ground displacement and pipe axial force at each interface of stable and sliding zones was obtained from closed-form solutions of governing differential equations, assuming both the stable and sliding zones are infinitely long. To prevent the overestimation of the axial strains in the pipe, a limiting scenario was considered where the soil was assumed to have yielded over the entire sliding zone. Equilibrium and compatibility equations were used to calculate the pipe axial forces and strains at the two interfaces. The simplified model for longitudinal ground movement was validated against finite element solutions. The validation example presented involves a 20-inch straight pipeline subjected to longitudinal ground movement over slide lengths of 50, 100 and 200 metres, as well as a semi-infinite sliding zone case.
A Systematic Material Evaluation Program for High Grade Line Pipe Materials
Authors: Duan Da-Ming , Zhou Joe , Rothwell Brian , Taylor David , Widenmaier Kevin
Published: July 2009

TransCanada Pipelines has decades of experience in both research and application of high grade materials in its pipeline systems. This evolution process has led to a unique way for the company to understand and evaluate high grade materials including X80, X100 and X120. As part of its pipeline construction quality management system, TransCanada has launched a systematic material evaluation program that, in addition to its pipe material specifications which were built on top of relevant CSA standards, specifies procedures for qualification and evaluation of line pipe materials. Consequently, a multi-tiered pipe material quality control system is established. The material evaluation program consists of both management procedures and technical procedures. This paper is to present the framework and the major components of the technical procedure. Due to the specific mechanical properties of high grade line pipe materials and their specific features of applications, material testing matrix is defined to evaluate not only the pipe body material but also girth welds made with modern pipeline welding technologies. For X80 pipes, while the program is concentrated for material qualification based on stress-based design requirements, a “further look” into the material properties is taken to evaluate the suitability of the pipe products to be applied under strain-based design conditions. For X100 and higher grade pipes, a full research test matrix is defined to explore the applicability of the material in strain-based design conditions, particularly the northern development design conditions.