bluuebunny/crossref_metadata_2025 huggingface dataset:
Connecting the Environmental Management System and Environmental Impact Assessment for Pipeline Projects
Authors: Lien Kent , Colosimo Ken J.
Published: July 2009

The National Energy Board of Canada (NEB) oversees all aspects, including environmental protection, of the construction and operation of hydrocarbon transmission pipelines under federal jurisdiction. The NEB’s regulatory approach is to minimize regulatory burden while maintaining a high standard of environmental protection. To achieve this, the NEB is working toward implementing a flexible, risk-based regulatory approach in which processes fit the scope and range of applications it receives. The NEB requires its regulated companies to develop and implement the equivalent of an environmental management system relating to all aspects of their business. In evaluating the companies’ compliance, the NEB conducts formal audits of these systems to ensure they are appropriately developed, maintained and implemented. The NEB has recently initiated changes to its regulatory processes to utilize companies’ management system information collected during the audits to enhance its application and assessment processes. This paper will discuss how concepts related to risk and management systems principles and information collected during an environmental management system audit can be integrated into a regulator’s environmental impact assessment for a proposed pipeline project. How knowledge and lessons learned are transferred through all stages of the pipeline life cycle will also be discussed.
Computational Analysis of Hydrogen Contribution to the Near-Neutral pH Stress Corrosion Cracking
Authors: Telitchev Igor Ye. , Vinogradov Oleg
Published: July 2009

Hydrogen plays a critical role in near-neutral pH SCC in pipelines, but the precise mechanism of its effect on crack initiation and propagation is still not well understood. Fundamentally, the process starts on the atomic level and at the root is dislocation formation and propagation due to various factors. In the present study a molecular statics simulation has been applied for the analysis of the contribution of hydrogen to the near-neutral pH stress corrosion cracking. A 3D crystal structure in which the interatomic forces between the hydrogen-iron and iron-iron atoms were defined, respectively, by the Morse and modified Morse potential functions was tested numerically. The model and the code developed were applied to both a hydrogen-free bcc iron crystal with the premade edge slit and to a bcc iron crystal with the hydrogen atoms aggregated near the crack tip. The width of the reference structure was chosen to be large enough to avoid any significant effects of free boundaries while preserving the basic properties of the structure. The edge slit was obtained by removing of a monolayer of iron; it was assumed that this slit was formed previously as a result of dissolution and the hydrogen-assisted cracking. Simulation results demonstrated that the presence of dissolved hydrogen causes severe distortion of the lattice and results in a weakened zone of interatomic bonds in the vicinity of the hydrogen atom even before the external load is applied to the structure. This phenomenon leads to the nucleation of nano-voids and later to the formation of edge dislocations array, and to the newly nucleated voids coalescing. Consequently the sliding processes start earlier (under the smaller load) leading to a 15–20% loss of residual strength in comparison with the hydrogen free sample.
Assessment of SCC Susceptibility of Supermartensitic Stainless Steel Through Slow Strain Rate Tests
Authors: Contreras A. , Espinosa-Medina M. A. , Salazar M.
Published: July 2009

The 13%Cr supermartensitic stainless steels (SMSS) are a new group used as pipelines for oil and gas transport. The optimized microstructure of these materials offers good corrosion resistance in environments containing CO2 and H2S. In addition to reducing carbide precipitation, the low carbon content (about 0.01 wt-%) of supermartensitic steels SMSS provides good weldability with conventional arc welding techniques. The susceptibility to stress corrosion cracking (SCC) through slow strain rate tests (SSRT) of SMSS and its comparison with a Hastelloy C-22 in substitute ocean water was carried out. Tests were supplemented by potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The SSRT were performed in air and in a chloride solution at 5, 15, 25 and 35°C. The susceptibility to SCC was evaluated considering the reduction in area ratio and time to failure ratio. According to these considerations it is clear that all the specimens tested in the chloride solution exhibited high resistance to chloride SCC. The specimens tested in air exhibited a ductile fracture. In the corrosive solution, the fracture was a combination of both, ductile and brittle fracture with a transgranular appearance. An evident temperature effect on the steel was observed. The major susceptibility to SCC was presented to the lower temperature (5°C). According to EIS evaluations, the corrosion rate increased with the temperature, which promoted an increase in the SCC susceptibility at a low temperature. The corrosion mechanism observed on the material under dynamic stress was a combination of high activation resistivity in combination with a diffusive process on the metallic interface given by a thin film of a protector layer of chromium oxide.
Assessment of Crack in Corrosion Defects in Natural Gas Transmission Pipelines
Authors: Cronin Duane , Plumtree Alan , Sen Millan , Kania Richard
Published: July 2009

Crack-like defects may occur coincident with corrosion defects and represent a new hybrid form of defect in gas and oil pipelines that is not directly addressed in the current codes or methods of assessment. There is a need to provide assessment and evaluate the integrity of the line as well as identify requirements for defect repair or line hydrotest. A numerical investigation was undertaken to evaluate the predicted collapse pressure of crack in corrosion (CIC) defects in typical line pipe. Longitudinally oriented CIC defects were evaluated as long cracks occurring within long, corrosion grooves of uniform depth. This was a conservative representation of a finite length CIC defect. It was found that the collapse pressure for CIC defects varied between that of a long uniform depth crack and a long uniform depth corrosion defect. The transition to corrosion defect behaviour only occurred when the corrosion defect depth was significant (greater than 75% of the total defect depth). Finite-length CIC defects were then investigated using a numerical investigation to identify the effect of crack and corrosion length. The collapse pressure of a finite length crack within an infinitely long corrosion defect was found to be lower than a crack of equivalent total depth and length. This reduction in collapse pressure was attributed to increased local stresses in the vicinity of the crack due to the coincident corrosion. The predicted collapse pressure increased towards the crack-only value when the length of the corrosion defect was decreased to that of the crack. CIC defects were evaluated as cracks using the NG-18 approach and BS 7910 code (Level 2A FAD). The NG-18 approach conservatively predicted lower collapse pressures than the FE analysis, whereas the FAD approach was conservative for shallow defects and could be non-conservative for deeper defects. These results are attributed to the presence of the corrosion and the fact that no factor of safety was included in the analysis. Future studies will investigate experimental validation of the FE and FAD methods for this type of defect.
Fracture Control in Carbon Dioxide Pipelines: The Effect of Impurities
Authors: Cosham Andrew , Eiber Robert J.
Published: July 2009

The fourth report from the Intergovernmental Panel on Climate Change states that “Warming of the climate system is unequivocal...” It further states that there is a “very high confidence that the global average net effect of human activities since 1750 has been one of warming.” One of the proposed technologies that may play a role in the transition to a low-carbon economy is carbon dioxide capture and storage (CCS). The widespread adoption of CCS will require the transportation of the CO2 from where it is captured to where it is to be stored. Pipelines can be expected to play a significant role in the required transportation infrastructure. The transportation of CO2 by long-distance transmission pipeline is established technology; there are examples of CO2 pipelines in USA, Europe and Africa. The required infrastructure for CCS may involve new pipelines and/or the change-of-use of existing pipelines from their current service to CO2 service. Fracture control is concerned with designing a pipeline with a high tolerance to defects introduced during manufacturing, construction and service; and preventing, or minimising the length of, long running fractures. The decompression characteristics of CO2 mean that CO2 pipelines may be more susceptible to long running fractures than hydrocarbon gas pipelines. Long running fractures in CO2 pipelines may be preventable by specifying a line pipe steel toughness that ensures that the ‘arrest pressure’ is greater than the ‘saturation pressure’ or by using mechanical crack arrestors. The preferred choice is control through steel toughness because it assures shorter fracture lengths. The ‘saturation pressure’ depends upon the operating temperature and pressure, and the composition of the fluid. ‘Captured’ CO2 may contain different types or proportions of impurities to ‘reservoir’ CO2. Impurities, such as hydrogen or methane, have a significant effect on the decompression characteristics of CO2, increasing the ‘saturation pressure’. The implication is that the presence of impurities means that a higher toughness is required for fracture arrest compared to that for pure CO2. The effect of impurities on the decompression characteristics of CO2 are investigated through the use of the BWRS equation of state. The results are compared with experimental data in the published literature. The implications for the development of a CCS transportation infrastructure are discussed.
Relaxation of In-Service Welding Procedure Flow Restrictions
Authors: Boring Matt A. , Sobilo Joe
Published: July 2009

Edison Welding Institute (EWI) and Enterprise Products Operating LP (Enterprise) worked together to develop an in-service welding program. The objective of this project was to relax flow restrictions on current in-service welding procedures to allow for welding onto liquid pipelines with flow rates outside of current flow limits. Enterprise’s current products include liquid propane, liquid ethane, and propane and ethane mixes in addition to other refined products. The current Enterprise in-service welding procedures restrict welding onto liquid pipelines with a flow rate between 1.3 and 4.0 ft/s (0.4 and 1.2 m/s). The minimum flow rate of 1.3 ft/s (0.4 m/s) was used because it was Enterprise’s minimal operating flow rate. The maximum flow rate of 4 ft/s (1.2 m/s) was grandfathered into the procedures. When welding onto an in-service pipeline to repair a damaged section of pipe or to install a branch connection (i.e., hot-tapping) there are two main concerns (burnthrough and hydrogen cracking) and both concerns needed to be evaluated for both flow conditions. The results from the project allow welding onto no-flow liquid pipelines with wall thicknesses between 0.25 and 0.5 in. (6.4 to 12.7 mm). Even though welding onto a no-flow thin-walled liquid pipeline [i.e., less than 0.25 in. (6.4 mm)] would not increase cracking susceptibility, the risk of burnthrough and eutectic iron formation would make the procedure unacceptable. The results of this project also indicated that acceptable welds can be made onto a high flow liquid pipeline [up to 12 ft/s (3.7 m/s)]. It was recommended, however, that Enterprise only use the temper bead welding procedures for such applications. Proper use of the temper bead welding procedures (i.e., proper heat input, weld toe spacing and stringent low hydrogen welding practice) has been shown to produce acceptable, crack-free welds. It is important to note that none of the welds showed signs of cracking, but the hardness levels of the heat input control procedures all exceeded the critical hardness level for their intended carbon equivalent materials. Increasing the flow rate from 4 to 12 ft/s (1.2 to 3.7 m/s) does appear to increase the cooling effect but it is not possible to determine the magnitude of the effect from the results of this work.
Improved Burnthrough Prediction Model for In-Service Welding Applications
Authors: Boring Matthew A. , Zhang Wei , Bruce William A.
Published: July 2009

When welding onto an in-service pipeline to repair a damaged section of pipe or to install a branch connection (i.e., hot-tapping) there are two main concerns; burnthrough and hydrogen cracking. The risk of burnthrough is typically evaluated by predicting the inside surface temperature of the pipeline using industry trusted computer models (e.g., Battelle or PRCI models). The objective of this project was to evaluate alternatives to the burnthrough prediction approach currently used by the Battelle and PRCI models and to identify and validate an improved approach. An improved approach for burnthrough prediction was developed and based on two-dimensional (2-D) thermo-mechanical FEA model which uses ABAQUS and EWI-developed proprietary user subroutines (46345 model). The easy-to-use graphic user interface (GUI) is based on Microsoft Excel and allows the user to run the numerical analysis by a few mouse-button clicks. The 46345 model was based on circumferential and bead-on-pipe welds which simulate the first layer of a temper bead in-service welding procedure or a weld metal deposition repair. The effect of various parameters such as pressure, wall thickness, pipe diameter, and welding direction were quantitatively studied using the 46345 model and compared to cross sections of experimental welds made under the same condition. The 46345 model circumferential weld case predictions were in good agreement with experimental weld cross sections and were able to reduce the over-conservatism assumed with the PRCI model. The 46345 model longitudinal weld case predictions were in less-than-adequate agreement with the experimental weld cross sections and were not able to reduce the over-conservatism assumed with the PRCI model. It is important to note that even though the 46345 model does predict the inside surface temperature during the analysis that the temperature is not used in determining the burnthrough risk. The burnthrough risk is solely based on the magnitude of the radial displacement which may be a better measure of burnthrough risk than the inside surface temperature.
Plastic Pipe Failure Analysis
Authors: Maupin Julie K.
Published: July 2009

The Gas Technology Institute is currently addressing the risks and threats to plastic pipes through research sponsored by the United States Department of Transportation, Pipeline and Hazardous Materials Safety Administration. With the upcoming proposed rulemaking, the United States distribution companies will be required to implement a distribution integrity management plan. In developing an integrity management plan, it is key to understand system risks and threats and with 39.6 million plastic services and nearly 620,000 miles of plastic gas main, the threats to plastic pipe need to be addressed. The research discussed in this paper identifies the types of failures that affect plastic piping, excluding third party damage. The paper also describes the most common cause of leaks, slow crack growth, as well as root cause analysis of a pipe removed from service due to leaking. The cause of leaks for five other pipe segments is also discussed. The final topic of this paper is rapid crack propagation and small-scale steady state testing.
Post Assessment of Ultrasonic Crack Detection Inline Inspection Data
Authors: Barkdull Lisa , Willems Herbert
Published: July 2009

The information supplied from inline inspection data is often used by pipeline operators to make mitigation and/or remediation decisions based on integrity management program requirements. It is common practice to apply industry accepted remaining strength pressure calculations (i.e. B31G, 0.85 dl, effective area) to the data analysis results from an inline inspection survey used for the detection and characterization of metal loss. Similar assessments of data analysis results from an ultrasonic crack detection survey require expert knowledge in the field of fracture mechanics and, just as importantly, require knowledge to understand the limitations of shear wave ultrasonic technology as applied to an inline inspection tool. Traditionally, crack-like and crack-field features have been classified with a maximum depth distributed over the entire length of the feature; crack-field features also have width reported. In an effort to provide further prioritization, techniques such as “longest length” or “interlinked length” [1] have been employed. More recently, an effort has been made to provide a depth profile of the crack-like or crack-field feature using the ultrasonic crack detection data analysis results. This presentation will discuss the advantages of post assessment of ultrasonic crack detection data analysis results to aid in the evaluation of pipeline integrity and discuss the limitations of advanced analysis techniques. Additionally, the potential for new inline inspection ultrasonic technologies which lend themselves to more accurate data analysis techniques will be reviewed.
CTOA Results for X65 and X100 Pipeline Steels: Influence of Displacement Rate
Authors: Reuven R. , McCowan C. , Drexler E. , Shtechman A. , Darcis Ph. , Treinen M. , Smith R. , Merritt J. , Siewert T. , McColskey J. D.
Published: July 2009

The toughness and plasticity of steel generally decreases with increasing testing rate. The crack tip opening angle (CTOA) was measured on two types of commercial pipeline steels API-X65 and API-X100, at a range of displacement rates to characterize rate effects. The testing was conducted at quasi-static and dynamic rates. The crosshead displacements in our test matrix ranged from 0.002 mm/s in the quasi-static mode to approximately 8000 mm/s in the dynamic mode. The quasi-static tests were conducted in a servo-hydraulic uniaxial test machine using Modified Double Cantilever Beam (MDCB) specimens. The dynamic experiments were made on a similar servo-hydraulic uniaxial test machine using the same type of specimen and with the addition of a disc spring setup for the fastest rate. The results of these tests indicate that the rate effect has negligible influence on the CTOA values measured for these materials for the reported rates. The CTOA values measured for the two materials show a small but convincing difference. The resistance to fracture was found to be higher for the X65 steel, as indicated by a higher CTOA and lower crack growth velocity. This paper presents results on the influence of displacement rates from quasi-static to dynamic for the X65 and X100 grade pipeline steels, and discusses a method for optimizing the reduction of the CTOA data.
Pipeline Integrity Management: Estimating and Prioritizing the Risk Resulting From Pipeline Facility Operations
Authors: Decker Larry C.
Published: July 2009

Recent efforts to develop a consistent approach to understanding the risk associated with operating a cross country pipeline have focused primarily on the pipe itself. Integrity management plans often include a prioritized risk profile that all but ignores the specific risks associated with operating tank farms, terminals, pumps and compression. This paper outlines a detailed logical approach that can be utilized to evaluate the relative safety, environmental and cost risk associated with operating diverse types of equipment within a pipeline station. Topics covered include the basic objectives of a facility risk model while providing the detail (granulation) necessary to continuously improve. A specific methodology is suggested as a systematic tactic to make an “apples to apples” comparison of diverse stations, lines and types of equipment, from a risk standpoint.
What Tools Are Available to Help Maintain a Code Compliant MAOP for a Highly Complex and Changing Gas Pipeline System?
Authors: Decker Larry C.
Published: July 2009

Companies that operate large and complex gas pipeline systems face the difficult task of maintaining those assets while complying with code and continuing to operate. Continuous system additions and changes, implemented by diverse groups across the company, result in tedious data driven studies to ensure that operating pressure strictly complies with code. This document presents a model and an approach that utilizes Geographic Information Systems (GIS) data to accurately and efficiently calculate a code-compliant Maximum Allowable Operating Pressure (MAOP), for systems that have thousands of miles of wide-ranging pipe segments and components.
Numerical Simulation Analysis of High Strength UOE Steel Pipes
Authors: Roza Juliana E. , Malatesta Giuliano , Fritz Marcelo C. , Mannucci Gianluca , Chad Luis , Ferino Jan , Silva Ronaldo C.
Published: July 2009

Large diameter longitudinally welded linepipes have to fulfil increasing technical requirements in order to guarantee best performance during construction and service. The increase in natural gas demand in European, North American, South American and Asian countries, foreseen for the immediate future, necessitates the development of cost effective transportation solutions to economically exploit gas fields located in remote area. A competitive option of gas to market is represented by the use of high-pressure natural gas transmission pipelines. In particular, for natural gas transportation over long distances, the use of high grade steel (X80, X100 or even higher) large diameter (36″ to 56″ of outer diameter), gas pipelines is found to be very attractive and economical. With respect to SAW pipes attention is focused on seam weld consumables and forming tools. In particular, forming tools must be designed in order to manage the large spring back effect that high grade plates, such as those for X100 pipes, exhibits when the pipes go from the U-press to the O-press. The objective of this paper is to present the evaluation of X100 pipes inside the UOE process from TenarisConfab mill with a mathematic modeling to get the best parameters. The X100 production process has been analyzed via Finite Element Model to evaluate goodness of tools geometry and pipe mill capability to produce higher grades pipes.
Maximize Flow Capacity on Corroded Liquid Pipelines: A Massive Defect Assessment Methodology Based Upon Hydraulic Simulations and ILI Results
Authors: Nicoletti E´rika S. M. , de Souza Antoˆnio Geraldo , Tolmasquim Suely Tiomno
Published: July 2009

Many aging liquid pipeline systems face demands to increase viscosity and/or flow capacity requirements. This paper presents a methodology to assure old pipelines’ up-rating serviceability by means of an optimizing integrity evaluation procedure where metal loss defects, reported by smart pig inspection, are assessed based upon maximum pressure profiles. The referred methodology comprises the following steps: 1. simulate the most severe pressure profiles scenarios for both steady and transient states and define maximum construct pressure envelopes; 2. build up representative equations of the maximum pressures observed at each profile point to steady/transient conditions; 3. assess pipe defects population reported by recent smart pig inspection considering the maximum pressure and the appropriate failure model; 4. determine rehabilitation hydrostatic testing pressures required to validate the new operating conditions; 5. re-assess pipe defects population considering the hydrostatic testing pressures. To illustrate the methodology applications, three case studies are presented, all carried out on pipelines older than 30 years. In order to accomplish the increased required capacity, four additional pump facilities were design and erected. Over thirty thousand metal loss defects (from ILI reported population greater than one million) were effective assessed for hydrostatic testing and operating conditions — considering individual pressure calculation. Regarding operating conditions, repair scenarios were constructed considering rehabilitation for a time interval of 5 years (based on estimated corrosion growth). The hydraulic simulations and the metal loss defect assessment where performed using, respectively, Pipeline STONER Simulator 9.3 and PLANPIG 2.0 software’s. This methodology has been successfully applied by PETROBRAS TRANSPORTE S.A. on revamping of corroded pipelines: despite the cases’ corrosion damage severity and the lack of conservatism on hydrostatic testing modeling, no test break was observed at the two tested lines and the required repairs number was dramatically reduced as compared to the traditional “as good as new” rehabilitation approach.
Mitigating Geohazards for International Pipeline Projects: Challenges and Lessons Learned
Authors: Nyman Douglas J. , Lee E. Mark , Audibert Jean M. E.
Published: July 2009

Permanent ground displacements (PGD) along or across pipeline alignments (e.g., landslides, surface fault rupture, and liquefaction) are the most significant seismic hazards for welded steel pipelines. A comprehensive summary of the methodology used to mitigate these hazards on major international oil and gas pipeline projects is presented along with a discussion of the ensuing implementation challenges. Key ingredients of pipeline geohazard mitigation include geohazard identification and characterization, assessment of rupture risk, pipeline/soil interaction analysis, strain-based design criteria, and weld strength and quality. The most significant problems arise from compressed schedules, which do not allow for the integration of this work. The paper begins with an overview of geohazards and their effects on pipelines with reference to industry rupture-rate statistics. It continues with a brief summary of geologic investigations, terrain evaluation, design criteria, design concepts, and engineering analysis techniques. Next, critical technical issues that often hamper progress and other problems typically encountered during project execution are identified. Suggestions for managing and coordinating geohazard mitigation within the context of preliminary and final project engineering phases of international projects are provided along with recommended approaches to avoid or lessen the impact of geohazard-related design and construction problems. The need for perceptive front-end planning is emphasized, especially as it relates to pipeline routing through potentially hazardous areas and interaction with regulators, government agencies, financiers, and other third-party organizations.
Fuel Optimization Using Biologically-Inspired Computational Models
Authors: Mora Thamar E. , Sesay Abu B. , Denzinger Jo¨rg , Golshan H. , Poissant G. , Konecnik C.
Published: July 2009

This paper presents a method for optimizing the fuel consumption of large and complex natural gas pipeline systems. The optimization method uses a biologically-inspired computational model, namely Particle Swarm Systems. The main objective is to identify the set of operating conditions that minimizes the use of fuel in compressor stations while maintaining the desired throughput and satisfying given system constraints. Solving this fuel optimization problem is non-trivial given the large number of decision variables and constraints in large networks, the nature of the fuel function and the minimum response time imposed by the frequent changes in flow nominations. The experimental evaluation tested on various subnetworks of TransCanada show that the proposed optimization approach meets TransCanada’s time requirements and reliably outperforms the interactive method that is the current state-of-the-art by providing solutions for which the fuel consumption is 12% less than state-of-the-art methods.
Modeling and CMOD Mapping of Surface-Cracked Wide Plates
Authors: Duan Da-Ming , Wang Yong-Yi , Chen Yaoshan , Zhou Joe
Published: July 2009

Curved wide plate (CWP) tests are frequently used to measure the tensile stress and strain capacity of pipeline girth welds. The parameters affecting the CWP measurement include specimen geometry and cooling setups. High-quality data is obtained when valid test conditions are confirmed. Crack mouth opening displacement (CMOD) is often measured in CWP tests. CMOD is a direct indicator of the amount of deformation at the cracked plane. It is an indirect indicator of the crack driving force (CDF) imparted on the crack. For a given test geometry and material, certain relationships can be derived between the measured CMOD and the more conventional representation of crack driving force, such as CTOD (crack tip opening displacement) and J-integral. Such relationships are a key element in fracture toughness testing standards. This kind of relationship is also particularly useful in strain-based design where CWP specimens are used for strain capacity and flaw growth prediction. In this paper finite element (FE) analysis is first used in modeling CWP testing conditions for X100 specimens with girth weld flaws to validate the test conditions. A novel approach called CMOD mapping is then developed to characterize the flaw behavior which, by making a direct use of CMOD test data from the CWP tests, is used to estimate the crack growth in the CWP. Finally analysis of strain limits using crack driving force (CDF) for the CWP specimens is also given by comparing experimental test data and FE estimation.
GIS Tools and Techniques for Environmental Assessment of Pipeline Construction
Authors: Danielson Erik C.
Published: July 2009

The purpose of this paper is to demonstrate GIS and GPS tools for the assessment and mapping of environmental features for natural gas pipeline construction projects. Environmental permitting of pipeline projects typically involve the integration of construction design drawings, GPS-delineated field data, and various Federal, State, or local GIS data layers. Accelerated project schedules and frequent changes to routes and construction footprints emphasize the need for efficient geoprocessing tools and procedures. A standard protocol for GPS field data collection of environmental features ensures consistency and facilitates analysis of the data. Geoprocessing tools such as linear referencing allow for rapid analysis of proximity and potential impacts. Interoperability tools in ArcGIS™ software facilitates integration of AutoCAD® or Microstation™ files provided by pipeline engineers and allow environmental layers to be converted for inclusion on alignment sheets. Cartographic tools and capabilities in ArcGIS provide an efficient means for generating maps and figures for reports.
Full-Scale Burst Tests of Ultra-High Pressured Rich-Gas Pipelines Under Buried and Unburied Conditions
Authors: Kawaguchi Shinobu , Murai Kazue , Hashimoto Yoshikazu , Hagiwara Naoto , Yajima Hidekuni , Toyoda Masao
Published: July 2009

The results of four full-scale burst tests conducted at the test site in Denmark were reported and the required fracture toughness for arrest was discussed for the X80 pipeline used for rich-gas transmission under ultra-high pressure (defined as greater than a 15 MPa internal pressure). The ductile crack arrest behavior was evaluated for buried using well-compacted sand and unburied conditions. The initial internal pressure of the tests was approximately 18.4 and 16.2 MPa corresponding to hoop stress of 400 and 350 MPa (72% SMYS and 64% SMYS), respectively. Natural gas that consisting of 89∼90 mol % methane and the balance being heavier hydrocarbons that give the rich-gas compositions was used for the burst tests. The outer diameters of the tested pipes were 762 mm (30-inch) and 610 mm (24-inch). The velocities of the propagated ductile cracks and the rich-gas decompression were determined from the data measured at the sampling rate of 25 kHz. Based on these test results, the required Charpy v-notch impact energy (vE energy) was used as a measure of the fracture resistance for arrest of the ductile propagating cracks evaluated under different backfill depth conditions. The applicability of the Battelle Two-Curve (BTC) approach was also investigated.
Justification of a Novel Pipe in Tunnel Approach to a River Crossing
Authors: Jandu Chas , Taylor Mike , Humphrey Stephen
Published: July 2009

As part of a major pipeline construction project, Laing O’Rourke had a requirement to install a section of pipeline beneath a river estuary. Due to a number of reasons it was not possible to negotiate the crossing using conventional techniques such as horizontal directional drilling (HDD) and an alternate method had to be sought. A feasibility study was undertaken and it was decided that a pipe-in-tunnel approach was the most viable. Due to constraints at the points of entry and exit it was necessary to cut two vertical shafts, one on each river bank. Linepipe sections were to be welded together, in the entry shaft, and pulled through the 2.44m diameter tunnel on plastic rollers, which were later to become the permanent supports during operation. On completion of the installation within the tunnel, two vertical sections of pipeline were to be installed in the shafts for connection to the main pipeline system. Due to the length of the crossing it was decided that back filling the void between the pipe and the tunnel wall with a suitable grout was not viable. A particular consideration was the likely occurrence of voids which would reduce the effectiveness of the CP system. For this reason, following installation, the tunnel was to be sealed with a concrete plug and flooded with water, and the shafts are to be backfilled with soil. This unique design arrangement presented a number of challenges and hence a requirement for the use of more complex modelling techniques than would normally be required. Models of the pipeline in various stages of installation were produced using the finite element software ABAQUS, with a variety of element types. Sets of rollers and their contact with the linepipe were also modelled. Soil loading, pressure, weight, buoyancy and temperature were applied to simulate a range of construction, commissioning and operational conditions. These were analysed, and the results were assessed for compliance with appropriate standards. Based on the results of the study it was possible to show that with a number of modifications to the original proposed design configuration, the crossing would be fit-for-purpose.
Crack Growth Model of Pipeline Steels in Near-Neutral pH Soil Environments
Authors: Chen Weixing , Kania R. , Worthingham R. , Kariyawasam S.
Published: July 2009

This paper reports the crack growth behavior of pipeline steels in near-neutral pH environments. Crack growth data both from laboratory tests using compact tension (CT) specimen and from full scale tests of shallow cracks were analyzed using a true corrosion-fatigue model established recently. It has been found that the crack growth rate can be correlated with ΔK2Kmax/fα, where ΔK is the stress intensity factor range; Kmax is the maximum stress intensity factor; f is the loading frequency; and α is a factor related to corrosivity of soil environments. This correlation enables determination of threshold ΔK2Kmax/fα values for long cracks such as in a test using CT specimen. The above growth correlation appears also true for small/shallow cracks in full scale tests except that small/shallow cracks were found to grow at appreciable rates below the threshold of long/deep cracks. Implications of the growth model to crack growth occurring in the field and pipe integrity management were also discussed in the paper.
Defect Assessment Using Effective Area Method From In-Line Inspection Data
Authors: McNealy Richard , Gao Ming , Limo´n-Tapia Sergio , Deaton Bill
Published: July 2009

When compared with the previous, more conservative methods of ASME B31G, failure pressure prediction of corroded pipelines using the effective area method (RSTRENG) has been demonstrated over time to be safe and has provided substantial economic benefit through the reduction of un-necessary repairs. In-Line Inspection technology has now developed to the point where approximations to effective area assessment can be provided based on in-line inspection data. This paper presents a method for determining if inspection performance is adequate to justify the use of effective area method based on in-line inspection data. Validation tests for the accuracy of effective area method in prediction of failure pressure from the original development work are cited and compared with the validated performance of effective area approximated from in-line inspection data.
Development of Risk Assessment Code Supplements for the UK Pipeline Codes IGE/TD/1 and PD 8010
Authors: Goodfellow Graham D. , Haswell Jane V. , McConnell Rod , Jackson Neil W.
Published: July 2009

The United Kingdom Onshore Pipeline Operators Association (UKOPA) was formed by UK pipeline operators to provide a common forum for representing pipeline operators interests in the safe management of pipelines. This includes ensuring that UK pipeline codes include best practice, and that there is a common view in terms of compliance with these codes. Major hazard cross country pipelines are laid on 3rd party land, and in general have an operational life typically greater than 50 years. The land use in the vicinity of any pipeline will change with time, and buildings will be constructed adjacent to the pipeline route. This can result in population density and proximity infringements, and the pipeline becoming non-compliant with the code. Accordingly, a land use planning system is applied so that the safety of, and risk to, developments in the vicinity of major hazard pipelines are assessed at the planning stage. In the UK, the Health & Safety Executive (HSE) are statutory consultees to this process, and they set a quantitative risk-based consultation zone around major hazard pipelines, where the risks to people and developments must be assessed. Quantitative risk assessment (QRA) requires expertise, and the results obtained are dependent upon consequence and failure models, input data, assumptions and criteria. UKOPA has worked to obtain cross-stakeholder agreement on how QRA is applied to land use planning assessments. A major part of the strategy to achieve this was the development of supplements for the UK design codes IGE/TD/1 and PD 8010, to provide authoritative and accepted guidance on the risk analysis of: i) Site specific pipeline details, for example increased wall thickness, pipeline protection (such as slabbing), depth of cover, damage type and failure mode, and ii) The impact of mitigation measures which could be applied as part of the development. The availability of this codified advice would ensure a standard and consistent approach, and reduce the potential for disagreement between stakeholders on the acceptability of proposed developments. This paper describes the guidance given in these code supplements in relation to consequence modelling, prediction of failure frequency, application of risk criteria, implementation of risk mitigation and summaries the assessment example provided.
Geotechnical Challenges for Design of a Crude Oil Pipeline Across an Active Normal Fault in an Urban Area
Authors: Keaton Jeffrey R. , Honegger Douglas G.
Published: July 2009

The proposed construction of a crude oil pipeline through a residential area north of Salt Lake City, Utah, with an alignment that crossed the Wasatch fault provides an interesting case history of the numerous uncertainties and competing constraints associated with designing a pipeline fault crossing in an urban environment. Several issues raised during project design needed to be resolved with representatives of the city in which the project was located; the city had obtained technical input from the state geological survey and a local pipeline engineering specialist. The definition of the fault location and design fault displacement required reconciling suggested fault displacement estimates that ranged from 2.4 m to 4.2 m. The desire on the part of the pipeline owner and the city to have the oil pipeline buried relatively deeply (at least 1.5 m of cover) needed to be resolved with the fact that improved pipeline performance for imposed fault displacements typically is achieved with shallower soil cover. Special trench construction measures to increase the pipeline fault displacement capacity, such as reduced burial combined with protective concrete slabs above the pipeline or use of geofoam material as trench backfill, needed to be balanced with potential consequences on normal pipeline operational and maintenance activities, as well as street maintenance by the city. Increases in pipe wall thickness, that would permit an increase in the burial depth of the pipeline, needed to be balanced with concerns regarding potential problems that could be created with the measurement quality of internal inspection devices. The requirement that the pipeline be located beneath city streets, including a 90° corner 125 m from the fault crossing, limited the ability of the pipeline to distribute axial strain developed as a result of the fault displacement and led to optimization of the pipeline bend geometry with respect to available space and impact on existing utility lines. Resolving these issues was facilitated by examining the pipeline response to a variety of postulated design alternatives using finite element analyses. The final design recommendations that satisfied the owner and city provided a reasonable assurance that the pipeline would maintain pressure integrity for a fault displacement of 3.75 m.
Material Development and Strain Capacity of Grade X100 High Strain Linepipe Produced by Heat Treatment Online Process
Authors: Ishikawa Nobuyuki , Okatsu Mitsuhiro , Shimamura Junji , Endo Shigeru , Shikanai Nobuo , Muraoka Ryuji , Kondo Joe , Suzuki Nobuhisa
Published: July 2009

Linepipes installed in permafrost ground or seismic region, where larger strains can be expected by ground movement, are required to have sufficient strain capacity in order to prevent local buckling or girth weld fracture. On the other hand, strain capacity of linepipes usually degreases with increasing strength, and this is one of the reasons for preventing wider use of high-grade linepipe for high strain application. Furthermore, external coating is necessary for corrosion resistance of pipe, but coating heat can cause strain-aged hardening, which results in increased yield strength and Y/T. Therefore, there is a strong demand for developing high strength linepipe for a high strain application with resistance to strain-aged hardening. Extensive studies to develop Grade X100 high strain linepipe have been conducted. One of the key technologies for improving strain capacity is dual-phase microstructural control. Steel plate with the microstructure including bainite and dispersed martensite-austenite constituent (MA) can be obtained by applying accelerated cooling followed by heat treatment online process (HOP). HOP is the induction heating process that enables rapid heating of the steel plates. Variety of microstructural control, such as fine carbide precipitation and MA formation, can be utilized by this newly developed heating process. One of the significant features of the HOP process is to improve resistance to strain-aged hardening. Increase in yield strength by coating can be minimized even for the Grade X100 linepipe. Trial production of X100 high strain linepipe with the size of 36″ OD and 15mm WT was conducted by applying the HOP process. Microstructural characteristics and mechanical properties of developed X100 linepipe are introduced in this paper. In order to evaluate compressive strain capacity of the developed pipe, full-scale pipe bending test was carried out by using the trial X100 high strain linepipe after external coating. Full scale bending test of developed X100 linepipe demonstrated sufficient compressive strain capacity even after external coating.
Management System for the Identification Risk, Qualification and Remediation of Geo-Hazards in Rocks and Residual Soils of the Camisea NG and NGL Pipelines
Authors: Vela´squez Marti´nez Fernando A. , Robles Robles Dimas Y.
Published: July 2009

An early identification of geo-hazards i.e. slides, fluvial erosion, eolic erosion, rainwater erosion among others and the subsequent mitigation and remediation of its effects on the Right of Way (ROW) and the pipelines, has prevented the occurrence of leaks in the Camisea NG and NGL Transportation System, which includes a 730 Km natural gas pipeline and a parallel 560 Km natural gas liquids pipeline, operated and maintained by Compan˜i´a de Gas del Amazonas (COGA). The Camisea Transportation System, traverse the Peruvian territory starting in Malvinas (Cusco). The NGL pipeline stops in Playa Loberi´a (Ica) and the NG pipeline stops in the City Gate, located in Luri´n (Lima). These pipelines traverse the Peruvian rainforest, the Andes Mountains and coastal areas. The intend of this paper is to describe the use of a Risk Matrix (RM) in order to calculate different risk levels for the prioritization of the geotechnical mitigation and stabilization works to be performed during the dry season of the Peruvian rainforest. The RM is a tool based on the so-called Safety Ratio, incorporating calculation parameters of the Security Factor used in the stability analysis of slopes. Once the work sites have been identified using the RM, the engineering design is performed, using geotechnical engineering techniques such as subsoil exploration, laboratory testing, mathematic modeling, designs and instrumentation. After the Geotechnical Engineering process has been completed, the Safety Ratio values estimated with the RM are replaced by Safety Factors. The paper concludes showing the benefits of the whole Risk Management System, which has been successfully applied in the first 200 Km of the ROW characterized by residual soils, slopes with more than 45° and 7000 mm in excess of rainfall per year.
Custody Transfer Management in Pipelines
Authors: Gavi´n Sergio D. , Gonella Maximiliano I.
Published: July 2009

This paper focuses on the technical study of metering systems involved in custody transfer (metering instruments and its patterns) in order to calculate a measurement uncertainty for each component and for the system as a whole. Based on this, a tolerance for the operating balance of each batch is established. This definition applies to monthly balances for all the quantity of product that travels into the pipeline and for kind of it (gasoline, diesel, etc.). This methodology, of managing the custody transfer for the global pipeline and by product, helps to early detections of failures at the metering systems. Also, valorizing the transferred product in the interface between two consecutive batches, the company counts on an economic indicator to improve the batch cut points. In addition, it makes possible to fix the Refinery’s ‘quality giveaway’ (“quality gift”) since the volume of the transferences is related closely to the quality of the transported product. The greater the quality ‘giveaway’, the lower the volume of transferences.