bluuebunny/crossref_metadata_2025 huggingface dataset:
Development and Production of Heavy Gauge X80 and High Strength X90 Pipeline Steels Utilizing TMCP/Optimized Cooling Process
Authors: Zhang Guodong , Bai Xuejun , Stalheim Douglas , Li Shaopo , Ding Wenhua
Published: December 2014

Along with the increasing demand of oil and natural gas by various world economies, the operating pressure of the pipeline is also increasing. Large diameter heavy wall X80 pipeline steel is widely used in the long distance high pressure oil and gas transportation in China today. In addition, development of X90/X100 has begun in earnest to support the growing energy needs of China. With the wide use of X80 steels, the production technology of this grade has become technically mature in the industry. Shougang Group Qinhuangdao Shouqin Metal Materials Co., Ltd. (SQS) since 2008 has been steadily developing heavier thicknesses and wider plate widths over the years. This development has resulted in stable mass production of X80 pipeline steel plate in heavy wall thicknesses for larger pipe OD applications.

The technical specifications of X80 heavy wall thickness and X90/X100 14.8–19.6 mm wall thicknesses, large OD (48″) requiring wide steel plates for the 3rd West-to-East Natural Gas Transmission Pipeline Project and the third line of Kazakhstan-China Main Gas Pipeline (The Middle Asia C Line) and the demonstration X90/X100 line (part of the 3rd West-East Project) in China required changes to the SQS plate mill process design. Considering the technology capability of steelmaking and the plate mill in SQS, a TMCP+OCP (Optimized Cooling Process) was developed to achieve stable X80 and X90/X100 mechanical properties in the steel plates while reducing alloy content.

This paper will describe the chemistry, rolling process, microstructure and mechanical properties of X80 pipeline steel plates produced by SQS for 52,000 mT of for the 3rd West-to-East Natural Gas Transmission Pipeline Project and 5,000 mT for the Middle Asia C Line Project along with 1000 tons of 16.3 mm X90/X100 for the 3rd West-East demonstration pipeline. The importance of the slab reheating process and rolling schedule will be discussed in the paper. In addition, the per pass reductions logic used during recrystallized rough rolling, and special emphasis on the reduction of the final roughing pass prior to the intermediate holding (transfer bar) resulting in a fine uniform prior austenite microstructure will be discussed. The optimized cooling (two phase cooling) application after finish rolling guarantees the steady control of the final bainitic microstructure with optimum MA phase for both grades. The plates produced by this process achieved good surface quality, had excellent flatness and mechanical properties. The pipes were produced via the JCOE pipe production process and had favorable forming properties and good weldability. Plate mechanical properties successfully transferred into the required final pipe mechanical properties. The paper will show that the TMCP+OCP produced X80 heavy wall and 16.3 mm X90 wide plates completely meet the technical requirements of the three pipeline projects.
Strain Based Design Versus Preheat for Hotbit Pipelines
Authors: King Graeme , Phiri Ian , Greenslade John
Published: December 2014

The first buried hot bitumen (hotbit) pipeline is now operating successfully in the Alberta oil sands north of Fort McMurray and more are on the way. These hotbit pipelines are designed to transport raw, undiluted bitumen to a central refining plant at temperatures up to 140°C. They are constructed in winter when the ground is frozen allowing heavy construction equipment to travel across the watery muskeg terrain without sinking. Construction continues even when atmospheric temperatures fall as low as −30°C. Hotbit pipelines are buried with more than 1.2 m of cover, which can prevent them from expanding when they are heated from their locked-in installation temperature to their operating temperature of 140°C. Large longitudinal compressive stresses induced by this restrained thermal expansion combined with high hoop tensile stresses due to internal pressure produce stresses in the pipe wall that exceed the maximum allowable combined stress of 90%SMYS specified in North American pipeline codes (ASME B31.4 and CSA Z662).

Two methods are available to handle these high combined stresses in hotbit pipelines. The first method is to expand the pipe during construction by preheating it to a temperature of approximately 90°C and then locking in the expansion by backfilling the pipeline trench before the pipe has had a chance to cool. By limiting the positive temperature differential between installation and operation to approximately 50°C, this method keeps thermally induced axial compressive stresses low enough that the combined stress does not exceed the allowable limit of 90%SMYS specified by pipeline codes.

In the second method, the pipeline is still constructed in winter but without preheating. Temperature differentials and thermally induced axial compressive forces are much higher than in the first method and carefully engineered restraint is require to prevent the pipe from failing by pushing out of the ground at bends or by either lateral or upheaval buckling of long straight sections in muskeg swamps and bogs. This method requires strain-based design principles to show that, when the pipeline is first heated to its operating temperature, large thermally induced compressive stresses in the pipe wall are acceptable because they dissipate without causing failure when the pipe steel yields.

Both methods are technically acceptable but require specialized pipeline engineering skills to implement them successfully. The first method incurs the cost of preheating and increased construction costs due to reduced pipe lay rates while the second method incurs the cost of more robust restraint systems, particularly at bends. Details of both methods are presented and discussed to determine which of the two methods has the least cost and the least risk.
Laboratory Testing of Full-Scale Pipes Partially Embedded in Soil to Study Soil-Pipe Interaction of Offshore Seabed Oil and Gas Pipelines: Initial Observations
Authors: Amarasinghe Ruslan S. , Wijewickreme Dharma , Eid Hisham T.
Published: December 2014

The geotechnical aspect of the design of off-shore oil and gas pipelines is a challenge due to inherent uncertainties in predicting soil-pipe interaction behaviour. Physical modeling is often sought after to gain insight into such problems. This is especially true for pipelines laid in deep waters that are partially embedded in the seabed. This paper presents initial observations arising from full-scale laboratory simulations of typical soil-pipe interaction scenarios of partially buried steel pipes. Bare and epoxy-coated NPS18 steel pipes, each measuring 2.5 m in length, were separately tested in a soil chamber by simulating: (i) lateral pipe displacement; and (ii) longitudinal pipe displacement, under partial embedment in two idealized soil bed models, i.e., in a coarse-grained soil bed model with full drainage, and a fully-saturated fine-grained soil bed model with partial drainage.
Risk and Reliability Modeling to Support Logistics Performance for Oil and Gas Terminals
Authors: Gonzalez Jose Luis Martinez , Taylor Irani Perez , Aguilar Jaime Cervantes , de la Escalera Lorenzo Martinez
Published: December 2014

The oil and gas industry has three major segments: upstream, midstream and downstream. Upstream is frequently referred to as exploration & production. The midstream segment involves transportation, storage and marketing of oil and gas products. Transportation options may vary from small connector pipelines to massive cargo vessels covering trans-ocean routes. Most oil types may be transported in their original condition, while natural gas needs to be either compressed or liquefied for transmission. Storage helps to balance fluctuations between supply and demand of energy products. Downstream covers the refining and processing of hydrocarbons into usable products. Each segment has facilities to support one or various processes. Terminals include pipeline, rail, trucks and cargo transmission which imply a complex model to cover the whole facility to evaluate risk and reliability with all processes and functions involved. Before addressing the logistics of each midstream component the reliability of the involved assets needs to be evaluated. First to be considered is terminal location with respect to upstream and downstream. Onshore and maritime terminals have several components in common and two main processes may coexist (storage and distribution). All terminal components represent circuits with a specific sub process or function. Some circuits have a serial arrangement so they are highly dependent on each other’s reliability. Also some circuits develop parallel processes with null or low impact on the terminal main process; however they may influence the facility risk in terms of probability of failure and consequences. Support and auxiliary circuits play an important role in terminal reliability since they could affect performance and continuity. There are circuits thought of as transmission and logistics elements, and that reliability is highly dependent on mechanical integrity to perform a specific function. Maritime terminals may have a circuit of SPM (Single Point Mooring) buoys for loading or uploading product. The analysis model has to include every circuit to cover any possible arrangement and configuration. The model is supported by a processes mapper that allows the user to define serial, parallel and support processes based on a logistics scheme in terms of reliability and mechanical integrity. The developed model provides results to support decision making for product transmission and distribution and addresses the importance of terminals in terms of risk and reliability for logistics planning. The terminals model is supported by 16 algorithms that may be used according to operator needs by simply activating or deactivating circuits to obtain values for probabilities of failure that predict any potential service interruption.
Effects of Notch Type and Loading Rate on CTOA of Modern X65 and X70 Pipe Steels
Authors: Xu S. , Sollen J. , Liang J. , Zavadil R. , Tyson W. R.
Published: December 2014

The crack-tip opening angle (CTOA) has been investigated as a fracture propagation resistance parameter for prevention of fast ductile fracture in gas pipelines. A CANMET simplified single specimen CTOA method has been proposed as a mill test and is being applied to characterize critical CTOA (CTOAc) of typical pipe steels to develop a toughness database and improve the test method.

In this work, tests using standard machined V-notch and API pressed notch (PN) drop-weight tear test (DWTT) specimens at quasi-static and impact rates were performed on modern X65 and X70 pipe steels typical of those used for CO2 pipelines. The rotation factor of the X65 steel deduced from the deformed ligament geometry is equivalent to those of X70 to X100 steels. Pressed-notch DWTT specimens were successfully fractured in impact and yielded CTOAc values equivalent to those of V-notched specimens following the CANMET recommended practice for determination of CTOAc. The effect of loading rate on CTOAc between the quasi-static and impact rates (covering five orders of magnitude) is small or negligible, being within experimental scatter. This is in agreement with data in the CANMET database, except for a low-toughness X52 steel that showed an increase in CTOAc between quasi-static and impact loading rates. The effect of flattening on CTOAc was also investigated and is small or negligible for the large-diameter (at least 508 mm) pipes tested in this work. The results may be used to support and improve a proposed test method for determination of CTOAc being considered by an ASTM Task Group and currently being evaluated in a round-robin testing program.
Verification and Validation of Pipeline Terminal Simulation Models
Authors: Lin Frank , Chegus Allan , Cernelev Dumitru
Published: December 2014

The problem of validating a complex simulation model represents pipeline terminal performance with verifiable accuracy is a difficult problem requiring extensive testing and calibration.

This paper discusses a case study of the verification and validation of a terminal simulation model. The approach to deciding model validity is presented as well as the process of verifying and validating the model including methodology and thresholds for acceptance. Ultimately the paper demonstrates the ability of commercial simulation and optimization software to work collaboratively to determine an optimal business solution.
Achieving Efficiency in Environmental Assessment Through Focused Selection of Valued Components
Authors: Prystay Ward , Pomeroy Andrea , Webster Sandra
Published: December 2014

Some of the largest oil and gas projects in Canada are currently being proposed in British Columbia. Establishing a fulsome and scientifically and socially defensible scope for environmental assessments in the oil and gas sector is a serious challenge for government and proponents. The approach taken by the federal National Energy Board to scope effects assessments on pipelines is quite different than the approach taken by the British Columbia Environmental Assessment Office on other types of oil and gas projects.

The NEB has published guidelines for scoping and conducting environmental and socio-economic assessments within its Filing Manual (National Energy Board [NEB] 2014). This manual sets out the expectations for scoping, baseline information, and effects assessments to be submitted as part of approval applications. Proponents are expected to provide all information necessary to meet the guidelines.

In British Columbia, the environmental assessment process is dictated by the British Columbia Environmental Assessment Act and includes a negotiated terms of reference for the assessment, called the Application Information Requirements (AIR). The approach to selection of valued components is guided by provincial guidelines (EAO, 2013). The first draft of the AIR is prepared by the proponent and is then amended to address matters raised by federal and provincial agencies, local governments, and representatives of potentially affected First Nations. Through two to three revisions, the scope of assessment is jointly established and then formally issued by the government.

While there are valid reasons for the differing federal and provincial approaches to scoping environmental assessments, each of these processes create risks for proponents in terms of project timelines and costs for preparing the environmental assessment. More specifically, the use of generic and negotiated guidelines can result in a number of issues including:

• A scope of assessment that is broader than necessary to understand the potential for significant adverse effects

• Inclusion of issues that are “near and dear” to a specific regulator or community but has no direct relationship to the effects of the project itself

• Selection of valued components that do not allow for defensible quantification of effects or use of directly relevant significance thresholds

• Selection of valued components that are only of indirect concern as opposed to focusing the assessment on the true concern.

• Double counting of environmental effects

• Risks in assessing cumulative effects

This paper discusses where and how these risks occur, and provides examples from recent and current environmental assessments for pipelines and facilities in British Columbia. Opportunities to manage the scope of assessment while providing a fulsome, efficient, effective and scientifically/socially defensible assessment are discussed.
Markovian Analysis of Aging Distributed Systems Remaining Life
Authors: Bushinskaya Anna , Timashev Sviatoslav
Published: December 2014

Correct assessment of the remaining life of distributed systems such as pipeline systems (PS) with defects plays a crucial role in solving the problem of their integrity.

Authors propose a methodology which allows estimating the random residual time (remaining life) of transition of a PS from its current state to a critical or limit state, based on available information on the sizes of the set of growing defects found during an in line inspection (ILI), followed by verification or direct assessment.

PS with many actively growing defects is a physical distributed system, which transits from one physical state to another. This transition finally leads to failure of its components, each component being a defect. Such process can be described by a Markov process.

The degradation of the PS (measured as monotonous deterioration of its failure pressure Pf (t)) is considered as a non-homogeneous pure death Markov process (NPDMP) of the continuous time and discrete states type. Failure pressure is calculated using one of the internationally recognized pipeline design codes: B13G, B31Gmod, DNV, Battelle and Shell-92.

The NPDMP is described by a system of non-homogeneous differential equations, which allows calculating the probability of defects failure pressure being in each of its possible states. On the basis of these probabilities the gamma-percent residual life of defects is calculated. In other words, the moment of time tγ is calculated, which is a random variable, when the failure pressure of pipeline defect Pf (tγ) > Pop, with probability γ, where Pop is the operating pressure. The developed methodology was successfully applied to a real life case, which is presented and discussed.
The COOLTRANS Research Programme: Learning for the Design of CO2 Pipelines
Authors: Barnett Julian , Cooper Russell
Published: December 2014

The COOLTRANS research programme is an £8 Million, three year (2011–2014) research and development project to identify, address and resolve key issues relating to the safe routeing, design, construction and operation of onshore pipelines transporting dense phase carbon dioxide (CO2) in the United Kingdom (UK). National Grid Carbon established and led the project. National Grid Carbon brought together major technical capability in academic and industry organisations in the UK and coordinated the research studies in order to provide a ‘fast-track’ for the identification and application of key learning to its ongoing pipeline projects. In particular, National Grid Carbon is pursuing plans to develop a pipeline network in the Humber and North Yorkshire areas of the UK to transport dense phase CO2 from major industrial emitters in the area to a saline aquifer off the Yorkshire coast. The COOLTRANS research programme has provided the technical foundations for the design and operation of CO2 pipelines in the UK. The paper highlights the key learning for the design of CO2 pipelines, and the specific application of the learning to the planned National Grid Carbon CO2 network in the Humber and North Yorkshire area of the UK.
Critical Condition for Hydrogen Induced Cold Cracking of High Strength Weld Metal
Authors: Ishikawa Nobuyuki , Sueyoshi Hitoshi , Endo Shigeru
Published: December 2014

The critical conditions of hydrogen content and residual stress in the high strength steel weld with the tensile strength level of over 980MPa were investigated. The critical hydrogen concentration for the cold cracking in the Y-grooved constraint weld joint was evaluated with intentionally introducing hydrogen gas. Residual stress conditions at the “root” portion in the weld joint were evaluated by the neutron diffraction technique. It was found that the root portion showed highest tensile stress of over 1110MPa in the transverse direction, and cracking occurred when the average hydrogen content was over 2ppm. In order to clarify the critical conditions of the principal tensile stress and local accumulated hydrogen concentration of the weld metal, the delayed fracture testing by using the notched round bar specimen with electrochemically hydrogen charged was conducted. It was seen that the cold cracking behavior in the Y-grooved weld joint was explained by the critical conditions of the maximum principal stress and the local accumulated hydrogen content obtained from the delayed fracture with the small specimen.
Modern Approach to the Microstructure Characterization of Large Diameter Linepipes
Authors: Stallybrass Charles , Frommert Matthias , Konrad Joachim , Meuser Heike , Schröder Jens
Published: December 2014

Over the past decades, the complexity of requirements regarding the properties of large-diameter linepipes has increased steadily. This is driven by factors such as increasing operating pressures or more hostile environmental conditions. Steel producers all over the world have responded to these demands by continuous development along the entire processing route from steelmaking to thermomechanical rolling and pipe production. Understanding the influence of the microstructure on pipe properties is a key element to extend the use of linepipe steels to more challenging conditions. For this reason, the techniques that are used for microstructure characterization are constantly refined.

The microstructure of modern microalloyed linepipe steels that are produced by thermomechanical rolling in combination with accelerated cooling depends strongly on the processing parameters during production. The grain size of the base metal is typically below 10 μm and may contain fractions of ferrite, bainite and M/A-constituents. Because of their size, these microstructure constituents are often not readily accessible to a quantitative analysis by classical light-optical microscopy. This was also found to be true within the heat-affected zone (HAZ) of large-diameter pipes. High-resolution scanning electron microscopy in combination with electron backscatter diffraction was found to offer a wide range of possibilities to characterize the microstructure quantitatively with regard to the effective grain size, the volume fraction of constituents and their variation over the wall thickness. The effects of variations in processing parameters in laboratory-scale trials on the microstructure and properties are illustrated. Based on these investigations, it was possible to refine the alloy design and processing parameters in order to improve the low-temperature toughness of the base metal of high strength plate material and the HAZ of longitudinal weld seams.
Intentional Destructive Testing: A Means for Establishing Mechanical Integrity
Authors: Alexander Chris , Vyvial Brent
Published: December 2014

Pipeline operators have at their disposal multiple resources for evaluating the integrity of identified features and anomalies. With advances in in-line inspection technology, the pipeline industry is being called upon to evaluate an ever-increasing number of features. When a feature is identified as a threat and severe enough to warrant further investigation, operators are faced with sometimes significant costs, including those associated with excavation activities.

In this paper the authors provide guidance on the benefits associated with full-scale testing for evaluating mechanical integrity, referred to Intentional Destructive Testing (IDT). Unlike many assessment techniques that require the development and implementation of assumed operating and boundary conditions, well-designed IDT programs are able to replicate in situ conditions to provide operators with a clear understanding regarding the behavior of pipeline features and anomalies by simulating operating conditions and loading.

Three case studies are included in this paper to demonstrate the merits of the IDT approach including the assessment of dents subjected to cyclic pressures, burst testing vintage pipes having long seam weld crack-like features, and evaluating the reinforcement of girth welds using composite materials. In using IDT operators have improved confidence in predicting the behavior of identified features to ensure that maintenance resources are properly allocated for excavating and repairing anomalies.
Mechanical Damage and Fatigue Assessment of Dented Pipelines Using FEA
Authors: Hanif W. , Kenny S.
Published: December 2014

Onshore and offshore pipelines may be subjected to mechanical damage during installation and operation due to environmental loads, external forces and third party interference. Pipelines in offshore environment may be prone to mechanical damage from events such as ice gouging, frost heave, and seismic fault movement. For conventional pipelines, the assessment of mechanical damage plays an important role in the development of integrity management programs that may be of greater significance for pipeline systems located in remote harsh environments and that are more prone to anchor drag, seismic loading and ice gouging.

This study examines the effect of dents and corrosion loss on pipe mechanical response using continuum finite element methods. ABAQUS/Standard (6.10-1) environment was used to simulate damage events and pipe response. Modelling procedures developed and calibrated against physical and numerical data sets available in public domain were reported previously in Hanif & Kenny 2012, 2013. Once confidence in numerical procedures was established, an analysis model matrix was established to account for a range of influential parameters including pipe/indenter geometry and pressure factor. A nonlinear multivariate regression analysis was conducted to develop strain based empirical tools that characterize the effects of local damage and applied loads on pipeline mechanical response for unconstrained dent conditions. Coupled affect of dent and artificial corrosion loss (in terms of wall thickness reduction in the damage zone) was also analyzed and a sensitivity study was conducted to see the effect of percentage wall loss on pipe response. Finally, operational parameters were varied and resulting stress concentration factors were calculated, that took into account indentations and wall loss, to predict fatigue life of dented pipe segments for both constrained and unconstrained dent conditions.
Application and Advancement of EMAT ILI Technologies for the Inspection of Cracks in Dents
Authors: Sutherland Jeff , Mann Andrew , Vignal Geoff , Maier Arne , Keane Sean
Published: December 2014

Pipeline dents and mechanical damage remain an integrity threat within the Oil & Gas pipeline industry. Such features typically consist of a localized deformation of the pipe wall.

Under certain conditions, cracking may develop within or adjacent to the area of deformation due to stress concentration factors resulting from the deformation itself or from secondary damage such as a scrape or gouge.

Conventional inline inspection technologies consistently to date have not explicitly addressed inspection capabilities for cracking within dents.

This paper presents the results of a collaborative technical effort to assess and advance the abilities of EMAT inline inspection technologies to identify and characterize such mechanical damage features as found in liquid pipelines.

The background and application of these advanced technologies for the targeted threats is discussed, as well as the experimental testing performed and results achieved.
Understanding State Variability and Recommendations for Minimizing Schedule Risk in Pipeline Siting and Development
Authors: Morton John H. , Rowe Steve T. , Hargrave Rosemary C. , Storey Catherine F. , White Stephanie L.
Published: December 2014

States are facing multiple challenges around new pipeline infrastructure as a result of unconventional oil and gas development. In many instances, federal oversight of interstate pipelines has failed to keep up with state interest in new pipelines. However, some states lack an efficient centralized or streamlined siting and permitting process to accommodate new development. This paper examines the different approaches by various states and what oil and gas companies can do to minimize risk by balancing the competing public and private interests to obtain the necessary permits and approvals without delaying project construction. The paper includes discussion of both Federal Energy Regulatory Commission (FERC) regulated natural gas pipelines as well as crude oil and product lines not regulated by FERC. In addition, this paper provides a first-hand perspective on how public opposition can change the regulatory landscape during the course of a project using the Keystone XL Project as an example. After the Keystone XL Project ran into permitting issues, the Nebraska Legislature modified its law, directing the state to evaluate the environmental, economic, social and other impacts of the Nebraska segment of the project. Because the state did not have a specific NEPA process, Nebraska had to first establish a process to conduct the state’s evaluation and produce the functional equivalent of a NEPA document, resulting in project delays. This paper also describes how the evolving use of social media has provided a mechanism for rapid dissemination of information for both project opponents and proponents. There is a heightened national awareness that may now target certain projects based on impacts to select environmental resources such that just meeting the minimum regulatory requirements may not be enough moving forward. In today’s regulatory environment, strategic planning and communications are critical to raise awareness in advance of the potential opposition.
Structural Reliability of Free Spanning Pipelines
Authors: Van den Abeele F. , Boël F. , Vanden Berghe J.-F.
Published: December 2014

When installing subsea pipelines on an uneven seabed, the free spans can be vulnerable to fatigue damage caused by vortex induced vibrations (VIV). Indeed, even moderate currents can induce vortex shedding, alternately at the top and the bottom of the pipeline, at a rate determined by the flow velocity. Each time a vortex sheds, a force is generated in both the in-line and cross-flow direction, causing an oscillatory multi-mode vibration. This vortex induced vibration can give rise to fatigue damage of submarine pipeline spans, especially in the vicinity of the girth welds. Traditional design for VIV is recommended in DNV-RP-F105, which limits the allowable free span length and implies whether (and when) seabed interventions are required.

The traditional DNV-RP-F105 design method is based on a semi-empirical approach, where the allowable span length depends on the pipe properties (diameter, wall thickness, coating, steel SN_curves, …), the sea state (current velocity, wave induced velocity and period) and the soil conditions (submerged unit weight, undrained shear strength, bearing capacity,…). All these input parameters, however, exhibit a certain extent of scatter and uncertainty.

This paper presents a risk based evaluation of free spans, by applying the principles of structural reliability theory to the problem of long free spanning pipelines subjected to VIV. First, a fully deterministic on-bottom roughness analysis is performed to introduce numerical tools for free span analysis. Then, a sensitivity analysis on soil parameters is presented to show significant influence of soil properties on free span predictions.

To study the implications of uncertainty in soil properties, a First Order Reliability Method (FORM) analysis is presented at the end of this paper, where the soil properties are introduced as stochastic variables.
Implementing a Geohazard Integrity Management Program: Statistics and Lessons Learned Over 15 Years
Authors: Baumgard Alex J. , Coultish Tara L. , Ferris Gerry W.
Published: December 2014

Over the last 15 years, BGC Engineering Inc. has developed and implemented a geohazards Integrity Management Program (IMP) with 12 major pipeline operators (consisting of gas and oil pipelines and of both gathering and transmission systems). Over this time, the program has been applied to the assessment of approximately 13,500 individual hydrotechnical and geotechnical geohazard sites spanning approximately 63,000 km of operating pipelines in Canada and the USA. Hydrotechnical (watercourse) and geotechnical (slope) hazards are the primary types of geohazards that have directly contributed to pipeline failures in Canada.

As with all IMPs, the core objectives of a geohazard management system are to ensure a proactive approach that is repeatable and defensible. In order to meet these objectives, the program allows for varying levels of intensity of inspection and a recommended timescale for completion of actions to manage the identified geohazards in accordance with the degree of hazard that the site poses to the pipeline. In this way, the sites are managed in a proactive manner while remaining flexible to accommodate the most current conditions at each site.

This paper will provide a background to the key components of the program related specifically to existing operating pipeline systems, present pertinent statistics on the occurrence of various types of geohazards based on the large dataset of inspections, and discuss some of the lessons learned in the form of program results and program challenges from implementing a geohazard integrity management system for a dozen operators with different ages of systems, complexity of pipeline networks, and in varied geographic settings.
Effects of Data Preparation on Leak Sensitivity Analysis
Authors: Noguerol Rafael , Unriza Juan Carlos , Acevedo Alberto
Published: December 2014

Determining the leak detection sensitivity for a particular system, or suggesting strategies to improve it are common challenges for leak detection professionals.

As an alternative to statistical analysis, an empirical approach can be employed: use an offline hydraulic simulator to model the pipeline system, including all the inaccuracies due to the instruments and communication systems. Using such an approach the sensitivity can be inferred by running some scenarios representative of leak and non-leak conditions. Furthermore, not only can normal operating conditions be considered but also emergency and/or upset operating conditions can also be taken into account.

Ecopetrol (the national Oil Company of Colombia) utilized this practical approach during the commissioning phase of a new pipeline allowing Ecopetrol to calculate the sensitivity prior to the commencement of operations. Analysis was also undertaken the results of which were recommendations on how to improve the system sensitivity.

This paper describes the methodology; the construction of the hydraulic model; the assumptions made, and presents the final results. A discussion about the validity of the procedure and its generic application is also presented.
Evaluation of Pressurized Cold Bend Pipe Body Tensile Fractures Under Bending Loads
Authors: Cakiroglu Celal , Kainat Muntaseer , Adeeb Samer , Cheng J. J. Roger , Sen Millan
Published: December 2014

Cold bending is applied at locations where the pipeline direction has to be changed in a horizontal or vertical plane. The process of cold bending usually results in residual stresses as well as changes in the material properties at the vicinity of the cold bend location which makes the study of the mechanical behaviour of cold bends indispensable. Due to discontinuous permafrost in arctic regions as well as slope instabilities and earthquakes cold bends within pipelines constructed in such locations can be subjected to significant tensile or compressive forces.

Experimental studies were carried out by Sen et al [1][2][3]in order to investigate the buckling behaviour of pressurized cold bends. In these experiments the curvature of the cold bend is increased in the presence of a constant internal pressure. In their experimental study a total of 8 full scale tests were conducted with a variety of pipe diameters, diameter to wall thickness ratio and steel grade. In this set of full scale tests one of the pipes with grade X65 failed due to fracture at the extrados after buckling and formation of wrinkles at the intrados[1].

Our previous work [4], [5] on this subject showed the simulations of this case using finite element analysis. These simulations demonstrated that indeed pipe body tensile side fracture can be observed for this particular pipe specification. Whereby the tension side fractures are expected starting from a specific internal pressure level. The simulation results showed that the equivalent plastic strain values at the cold bend extrados increase dramatically starting from a certain level of applied curvature in load cases with an internal pressure higher than a transition value. In this paper the effect of steel grade on this transition from compressive to tensile failure is investigated. Parametric studies are conducted for the entire range of steel grades tested in the experimental study of Sen et al. It is found that there is a linear proportionality between the steel grade and the transition internal pressure for steel grades between X60 and X80.
Enhancing Tensile Strain Capacity Through the Optimization of Weld Profiles
Authors: Wang Yong-Yi , Chen Yaoshan , Salama Mamdouh
Published: December 2014

In order to optimize cost and performance of high pressure gas pipelines by reducing the wall thickness, pipeline companies are considering the use of higher grade (X70 or above) steels or a composite pipe of thin steel liner and fiber wrap. The use of high strength steels and thinner pipes can result in challenges when the pipe is installed in areas imposing high strain demand such as discontinuous permafrost regions. For high strength steels, the difficulty of ensuring the strength overmatching of the weld metal and the potential softening of the heat affected zone (HAZ) can result in gross strain concentration in the weld region and thus reduce the strain capacity of the pipeline in the presence of weld defects. Also, a thinner pipe has lower strain capacity than a thicker pipe for the weld defect of the same dimensions. One of the economical and effective ways of mitigating the possibility of gross strain concentration and increasing the strain capacity of a weld region containing weld defects is through the use of appropriate weld profiles. For instance, adding a smooth and wide layer of weld reinforcement (termed weld overbuild) can increase the effective strength of the weld.

The effectiveness of the weld overbuild in improving the tensile strain capacity of girth welds is evaluated using the Level 4a approach of the PRCI-CRES tensile strain models. The crack-driving force is obtained through finite element analysis (FEA) of welds with planar weld and HAZ flaws of various sizes. It was demonstrated that weld overbuild with appropriate dimensions is an effective method to increase the tensile strain capacity (TSC) of girth welds which may have limited TSC without the overbuild. The role of weld profiles in girth weld integrity is discussed from the perspectives of historical evidence and more recent analysis and experimental tests.
Transient Modeling of Surge Pressures Within Injection Terminal Facilities
Authors: Perez Emma , Thomson Leanne
Published: December 2014

Pressure transients in piping systems occur whenever there is a change in fluid velocity. If this change is large enough, the pressure wave produced can exceed the Maximum Operating Pressure (MOP) of the system. Canadian and US regulations allow liquid petroleum systems to exceed the MOP under abnormal operating conditions however these surges cannot exceed 110% of MOP even for short periods of time. As part of meeting these regulations, the authors have applied complex computational modeling tools, developed methodologies, and company standards to identify sources of pressure surges, with the ultimate purpose of providing protection solutions useful for mitigating overpressures in oil injection facilities with low rated piping. These computational models and identification methodologies are based on a) abnormal operating conditions recorded in the past, b) potential worst case scenarios of terminal transients, and c) are particularly sensitive to input data such as piping characteristics, fluid types, and the initial states of the operating system. Our paper discusses the above mentioned transient simulation methodologies and their importance in meeting regulations.
Real Time Automatic Calibration of Flow Meters for Real-Time Hydraulic Modelling
Authors: Okungbowa Norense , Rostamy Noorallah
Published: December 2014

Performance of flow meters is often a function of flow rate as well as properties (density and viscosity) of the fluid measured by the meters. Since comparison of flow meter readings is a key parameter in leak detection techniques, it is desirable that the readings from the flow meters are accurate and comparable. The idea behind real-time calibration of flow meters is to calibrate a flow meter (called the dependent flow meter) against another flow meter (called the independent flow meter) that is assumed to read correctly. The real-time calibration method is useful under two main conditions: i) when the reference flow meter has been calibrated to a high degree of accuracy and the flow readings from the meter are accurate; ii) when the pipeline operating conditions support the fact that the meter-in flow at one station equals the meter-out flow at the other station. By determining the deviation of the dependent flow meter reading from the independent flow meter reading, a time-averaged flow ratio is calculated. However, the flow ratio calculation and time averaging is only updated at prescribed conditions. The proper correction factor is ascertained and then applied to the dependent flow meter reading. The main advantage of using this technique is that the flow meter repeatability is reduced over time below the nominal accuracy of the dependent meter. Note that the term “calibration” in this context does not refer to the standard method of calibrating flow meter with a ‘prover’ but a technique to calculate correction multiplier for flow meter in other to improve the performance of hydraulic models.
Risk Management for Lateral Channel Movement at Pipeline Water Crossings
Authors: Bracic Jan J. , Malcovish Craig , Yaremko Eugene
Published: December 2014

Pembina Pipeline Corporation (Pembina) owns and operates close to 10,000 km of crude, natural gas liquids (NGL), and natural gas pipelines across North America, with the majority of assets in western Alberta and eastern British Columbia. The Pembina pipeline network includes over 1,600 river and stream crossings, most of which are subject to varying degrees of vertical and/or lateral erosion. 1,260 crossings were in Alberta at the onset of the study.

Identifying potential lateral erosion hazards is a critical component of geohazard management program for pipeline integrity. In 2012, Pembina initiated a three-phase program to proactively address lateral-stability issues at river and stream crossings in Alberta: phase one identified and short-listed crossings that have potential lateral channel-shifting problems; phase two assessed which short-listed crossings have insufficient cover depth to accommodate the potential channel-shifting activities and ranked these crossings as high risk of exposure; and phase three will develop plans for repair and/or replacement of the high-risk crossings. Through this program, Pembina explores the significance of lateral erosion and encroachment at pipeline water crossings of various vintages, with regards to pipeline integrity.

This paper provides discussion as to how crossing geohazard risks are identified, with particular emphasis on stream bank erosion, and how this fits into Pembina’s overall risk management program. As well, selected case studies are provided.
Numerical Model for Unstable Ductile Crack Propagation/Arrest in Natural Gas Pipelines Incorporating Soil Backfill Effect
Authors: Nakai Hiroaki , Aihara Shuji , Misawa Kei
Published: December 2014

Prevention of unstable ductile crack propagation is one of crucial issues in pipeline industry. Some numerical methods for predicting unstable ductile crack propagation/arrest have been developed, of which the Battelle Two-Curve Method (TCM) and the HLP method have been most widely used. Although these two methods are simple and useful, they contain empirical parameters based on the data of full-scale pipe burst tests. Therefore, their applicable range might be limited; their prediction accuracy reportedly drops when applied to the burst tests using new grade pipes and CO2 pipeline burst tests. To overcome their shortcomings, the authors developed a new model, hereafter called “UT model”, without empirical parameters. The UT model describes pipe deformation and gas decompression by one-dimensional partial differential equations, and judges crack propagation/arrest using dynamic energy balance. In addition, the UT model is fully-coupled model which means that the interaction among pipe deformation, gas decompression and crack propagation is considered. Also, soil backfill effect, which constrains pipe deformation, is incorporated into the UT model; kinetic energy of soil surrounding a pipe is dealt as added density of a pipe. In the present paper, the UT model is described in detail, and applied to natural gas pipe burst tests both with and without soil backfill.
Spiraeoside inhibits mast cells activation and IgE-mediated allergic responses by suppressing phospholipase C-γ-mediated signaling
Authors: Kim Jung Kuk , Seo Young-Kyo , Park Sehoon , Park Soo-Ah , Lim Seyoung , Lee Susie , Kwon Ohman , Seo Jeong Kon , Choi Ung-Kyu , Ryu Sung Ho , Suh Pann-Ghill
Published: December 2014

Mast cells are responsible for IgE-mediated allergic responses through the secretion of various inflammatory cytokines and mediators. Therefore, the pharmacological regulation of mast cell activation is an important goal in the development of novel anti-allergic drugs. In this study, we found that spiraeoside (SP) inhibits mast cell activation and allergic responses in vivo. SP dose-dependently inhibited the degranulation induced by IgE-antigen (Ag) stimulation in RBL-2H3 mast cells without cytotoxic effects. At the molecular level, SP reduced the Ag-induced phosphorylation and subsequent activation of phospholipase C-γ2 (PLC-γ2). Moreover, SP inhibited the phosphorylation of spleen tyrosine kinase (Syk), linker for activation of T cells (LAT), and downstream MAPKs, such as ERK1/2, p38, and JNK, eventually attenuating expression of TNF-α and IL-4. Finally, we found that SP significantly inhibited IgE-mediated passive cutaneous anaphylaxis (PCA) in mice. Taken together, our results strongly suggest that SP suppresses IgE-mediated mast cell activation and allergic responses by inhibiting Lyn-induced PLC-γ2/MAPK signaling in mast cells.