bluuebunny/crossref_metadata_2025 huggingface dataset:
TCPL In-Line Inspection Management Program
Authors: Vieth Patrick H. , Sahney Reena , Ashworth Blaine
Published: October 2016

TransCanada PipeLines (TCPL) has developed a formalized in-line inspection management program to encompass all aspects of their inspection activities. The need for this formalized program was recognized while implementing an aggressive inspection program planned through the year 2000. The formalized inspection management program developed by TCPL ensures consistent and thorough handling of the data and maximizes the benefits of conducting an in-line inspection.
Strain Estimation Using Vetco Deformation Tool Data
Authors: Rosenfeld Michael J. , Porter Patrick C. , Cox James A.
Published: October 2016

Damage to pipelines in the form of indentations and third-party damage has emerged as a key concern for operating reliability and public safety within the pipeline industry. Many operators have conducted detailed surveys of their pipelines for indentations (or simply “dents”) by means of in-line inspection tools designed to detect, measure, and report the presence, size, and location of dents, as well as other deformations such as buckles or wrinkles and ovality.

Described herein is a technique suitable for processing the signal from Tuboscope-Vetco deformation ILI tools in order to derive the local cold strain associated with indentation of the pipe.
The Role of Coatings in the Development of Corrosion and Stress Corrosion Cracking on Gas Transmission Pipelines
Authors: Wilmott Martyn , Erno Brian , Jack Tom , Worthingham Robert
Published: October 2016

In order to protect pipelines against corrosion and stress corrosion cracking NOVA Gas Transmission (NGT) has employed a dual system involving the application of an insulating coating and effective cathodic protection to all pipelines. Since the installation of pipelines in the 1950’s the coatings of choice have changed with time. Construction in the 1950’s and 1960’s employed asphalt products which were hot applied over the ditch. Subsequently in the 1960’s and 1970’s polyethylene tape coatings were used extensively. Today the coatings of choice on the NGT system are fusion bond epoxies and extruded polyethylene systems.

This variety in the types of coating employed to protect pipelines against corrosion has necessitated a requirement to understand the long term performance of coating products. Studies at NOVA Research & Technology Corporation have been aimed at developing an understanding of the modes of failure of coating systems. The mode of failure of a specific coating system can impact significantly on the nature and severity of the resultant corrosion scenarios. Different coating systems under identical field conditions can fail in completely different ways. Examples from field coating failures will be described which show the significance of the mode of failure with respect to corrosion and stress corrosion cracking.

Laboratory studies using polyethylene tape, asphalt enamels and fusion bond epoxy coatings will be described which clearly demonstrate that coating failure modes are a key with respect to the type of corrosion scenario that is ultimately developed at the steel surface.

Such information is important in the development of site specific risk assessment models for the management of pipeline integrity.
High-pH SCC: Temperature and Potential Dependence for Cracking in Field Environments
Authors: Beavers John A. , Durr Carolyn L. , Delanty Burke S.
Published: October 2016

The objective of the work described in this paper was to establish the temperature and potential dependence for propagation of high-pH stress corrosion cracking (SCC) in field environments encountered on TransCanada PipeLine’s system in western Canada. Potentiodynamic and potentiostatic polarization techniques were used to identify the electrochemical potential range for performing SCC tests in the simulated field electrolytes. A slow strain rate technique was used for the SCC assessment. A standard 1N Na2CO3 – 1N NaHCO3 solution was included in the test program as a control. The more dilute simulated field electrolyte was a less potent cracking environment than the 1N Na2CO3 – 1N NaHCO3 solution in that the potential range for cracking was narrower and the maximum cracking velocity was lower at a given temperature. The center of the potential range for cracking with the simulated field electrolyte was consistently more negative than with the 1N Na2CO3 – 1N NaHCO3 solution. This may increase the likelihood that the pipe-to-soil potential of a cathodically protected pipeline lies in the cracking range.
A Review of the Concept of Mildly Sour Environments
Authors: Pargeter Richard J.
Published: October 2016

Published data on the effects of different levels of hydrogen sulphide (H2S) and pH in aqueous environments on steels have been reviewed. Both sulphide stress corrosion cracking (SSCC) and hydrogen pressure induced cracking (HPIC) have been considered. The data have been collated and presented on one diagram, and the appropriateness of setting relaxed hardness controls for ‘mildly sour’ environmental conditions has been discussed.
Effects of Hydrostatic Testing on the Growth of Stress-Corrosion Cracks
Authors: Zheng W. , Tyson W. R. , Revie R. W. , Shen G. , Braid J. E. M.
Published: October 2016

Two hydrostatic tests were carried out on an X-52 (Grade 359) pipe containing sixteen cracks of depths up to 55% wall thickness. Stress corrosion cracking (SCC) growth rates were measured in full-scale tests performed before and after the first hydrotest in order to demonstrate the effects of hydrostatic testing on subsequent crack growth rates. The effects on crack tip deformation were investigated by metallographic examination of crack cross-sections immediately following the second hydrotest.

The SCC tests were performed using a saw-tooth type load spectrum with the maximum stress set at 95% of the actual (as opposed to specified minimum) yield strength of the linepipe and R = 0.8. During the first hydrotest, the maximum applied stress was 108% of the yield stress; the total hoop strain in the pipe body reached about 0.2%, which is less than would have been reached in a uniaxial tensile test at this stress level because of the effect of the biaxial stress state in the pipe. The highest SCC growth rate measured before the first hydrotest was about 0.88 mm per year (2.4 * 10−3 mm/day), and the growth rate of the same crack after this hydrotest was about 0.37 mm per year (0.79 * 10−3 mm/day). The other cracks all showed varying degrees of reduction in growth rate.

Post-mortem examination indicated that the hydrotests did not cause significant crack blunting. The beneficial effects of hydrotests are attributed primarily to the presence of compressive residual stresses in the heavily deformed region in front of the crack tip.

The majority of cracks showed some growth during the first hydrotest. SCC growth and growth during the hydrotests are associated with distinctly different microscopic features on the fracture surface.
Hydrogen Effects in Gas Transmission Pipeline Steels
Authors: Maccagno T. M. , Ikeda-Cameron K. , Jack T. , Wilmott M. , Chen W. X. , Dorling D.
Published: October 2016

Six steels were obtained from excavations of in-service gas transmission pipelines, and subjected to hydrogen charging by electrochemical means. The aim was to assess the susceptibility to hydrogen damage of these materials, which were not expected to encounter hydrogen-containing environments when they were originally put into service, but which are now found to be vulnerable to hydrogen exposure under certain external environmental conditions. For all the steels, the H concentration was found to increase as the applied current density increased, but each material developed different concentrations at a given current density. In addition, all the steels exhibited increasing hydrogen blistering as the H concentration was increased, but each material displayed its own characteristic propensity to blistering. It was possible to identify a threshold concentration for the onset of blistering in each steel, and on this basis, two grade X46 pipes and a grade X70 pipe were found to be the most susceptible to hydrogen damage, while a X52 and a X56 pipe were the least susceptible.
Variations in Stress Concentration Factors Near Simulated Corrosion Pits as Monitored by Magnetic Flux Leakage, Magnetic Barkhausen Noise and Neutron Diffraction
Authors: Clapham L. , Mandal K. , Sabet-Sharghi R. , Atherton D. L. , Holden T. , Teitsma A. , Laursen P. , Mergeles B.
Published: October 2016

The conditions under which a pit defect is formed in a pipe can influence local stress concentrations which, in turn, affect the Magnetic Flux Leakage (MFL) signal. In this study MFL, Magnetic Barkhausen Noise (MBN) and neutron diffraction (ND) techniques are used to monitor and compare the local stress distributions surrounding simulated pits in plate and pipeline samples. Our study shows two important findings. Firstly, mechanically machining of simulated corrosion pits creates considerable machining stresses around the defect Conversely, electrochemical machining (ECM) produces no measurable residual stresses. Secondly, all three techniques indicate that, provided stresses are high enough hr produce local yielding, there are significant differences in local stress concentrations depending on whether the pit was electrochemically machined prior to stress application or while the sample was under stress. The latter case is more relevant to pipelines which corrode whilst in service since operating line pressures normally produce pipe wall hoop stresses of up to 70% yield strength.
Initiation of Environment Induced Cracking in Pipeline Steel: Microstructural Correlations
Authors: Wang Y.-Z. , Revie R. W. , Shehata M. T. , Parkins R. N. , Krist K.
Published: October 2016

Initiation of environment-induced cracks in pipeline steels involves interactions among microstructural features, loading conditions and environmental variables. Cyclic, or dynamic, loading has an important role in crack initiation, a competitive process in which cracks form first at the most favorable sites.

Under simultaneous cyclic loading and exposure of a Grade 448 (X-65) pipeline steel to aqueous solution of near-neutral pH, NS-4 solution saturated either with CO2 or 5% CO2/ balance N2, cracks that initiated early in the process were associated with pits. A correlation between pits and non-metallic inclusions has been observed. Other locations favorable for localized corrosion attack, such as along the steel surface at the edge of a coating, were also found to be sites for crack initiation. The dense population of cracks that appeared at a later stage of exposure most likely developed from slip-dissolution along certain crystallographic planes. Cracks that formed at an early stage did not always remain as the largest cracks, as crack coalescence, dormancy and/or re-activation, as well as initiation of new cracks, all occurred simultaneously on different parts of the exposure surface.
Full-Scale Wrinkling Tests and Analyses of Large Diameter Corroded Pipes
Authors: Smith Marina Q. , Nicolella Daniel P. , Waldhart Christopher J.
Published: October 2016

The aging of pipeline infrastructures has increased concern for the integrity of pipelines exhibiting non-perforating wall loss and settlement induced bending. While pressure based guidelines exist which allow pipeline operators to define operational margins of safety against rupture (e.g.; ANSI/ASME B31-G and RSTRENG (Battelle, 1989)), reliable procedures for the prediction of wrinkling in degraded pipes subjected to combined loading are virtually non-existent. This paper describes full-scale testing and finite element investigations performed in support of the development of accurate wrinkling prediction procedures for the Alyeska Pipeline Service Company. The procedures are applicable to corroded pipes subjected to combined loading such as longitudinal bending, internal pressure, and axial compression.

During the test program, full-scale 48-inch diameter sections of the trans-Alaska pipeline were subjected to internal pressure and loads designed to simulate longitudinal bending from settlement, axial compression from the transport of hot oil, and the axial restraint present in buried pipe. Load magnitudes were designed based on normal and maximum operating conditions. Corrosion in the pipe section is simulated by mechanically reducing the wall thickness of the pipe. The size and depth of the thinned region is defined prior to each test, and attempts to bound the dimensions of depth, axial length, and hoop length for the general corrosion observed in-service.

The analytical program utilizes finite element analyses that include the nonlinear anisotropic material behavior of the pipe steel through use of a multilinear kinematic hardening plasticity model. As in the tests, corrosion is simulated in the analyses by a section of reduced wall thickness, and loads and boundary constraints applied to the numerical model exactly emulate those applied in the full-scale tests.

Verification of the model accuracy is established through a critical comparison of the simulated pipe structural behavior and the full-scale tests. Results of the comparisons show good correlation with measurements of the pipe curvature, deflections, and moment capacity at wrinkling. The validated analysis procedure is subsequently used to conduct parameter studies, the results of which complete a database of wrinkling conditions for a variety of corrosion sizes and loading conditions.
Correction for Longitudinal Stress in the Assessment of Corroded Line Pipe
Authors: Roberts K. Andrew , Pick Roy J.
Published: October 2016

It is common to assess corroded line pipe using ASME B31-G, its Canadian equivalent CSA Z662 Clause 10.8.2, or more recently RSTRENG. These techniques consider only the circumferential stress in the pipe in predicting the burst pressure of corroded pipe. This paper describes the results of experiments and finite element modeling to investigate the effect of longitudinal stress on the burst pressure of pipe with isolated corrosion pits. The results are used to develop a correction factor applicable to the assessment procedures listed above.
Application of Material Standards and ISO Quality Management Systems
Authors: Coulson Keith E. W. , Quinton Dennis G. , Slimmon Thomas C.
Published: October 2016

Since the early 1970’s, the pipeline construction and operation industry has supported the development and implementation of various material standards and specifications. The emphases within the pipeline energy industry was to standardize manufacturing and performance testing processes in the provision of a product which would ensure public safety and reliability of service. The pipeline segment of the energy industry has succeeded in incorporating minimum quality levels by way of industry standards, codes, regulatory requirements and propriety company standards. In addition to these minimum product requirements quality assurance programs have been introduced to enhance the likelihood of conformance to the applicable requirements. In 1975, Canada became the first country to prepare and publish quality system standards for commercial use (Z299 standards). International quality system standards development proliferated in the following years, leading to the establishment of the ISO/TC 176 work team which subsequently led to the issue of the internationally accepted ISO 9000 series of standards.

This paper will review both the concept and stages of development of CSA pipe and coating standards. It will also analyze the impact that international standards for Quality Management Systems are having in establishing systematic approaches to assessing levels of quality during material manufacture. Finally, a vision of the possible road to the future will be drawn and the positive impacts for the pipeline industry will be projected from a full life cycle cost perspective.
The Australian Petroleum Pipeline Code AS 2885 - 1997
Authors: Bilston Ken J. , Fletcher Leigh
Published: October 2016

The Australian Standard AS 2885 - 1997 Pipelines Gas and Liquid Petroleum contains mandatory risk assessment procedures which are deeply integrated into route selection, design and operation and maintenance. The procedures require systematic identification and assessment of threats which are specific to the pipeline, the location, the threat itself and its effect on the pipeline. External interference protection design is one fundamental step in the risk assessment procedure which involves formal specification of physical measures for the prevention of damage and procedural measures for the prevention if incidents with the potential to cause external interference. A land classification system based on land use and design which separates the design factor for pressure containment from the requirements for other engineering parameters combine to ensure that economy, reliability and public safety are optimised together. A fracture control plan is required as part of the integrated design process and the plan requires formal and systematic treatment of fluid composition and type and fracture arrest length. The welding section of the standard differs significantly from API 1104 and includes fitness-for-purpose defect acceptance limits based on the EPRG guidelines.
Reliability of Mechanised UT Systems to Inspect Girth Welds During Pipeline Construction
Authors: de Raad Jan A.
Published: October 2016

As an alternative to radiography, a field-proven mechanized ultrasonic inspection system is discussed. Called Rotoscan, this system has been developed for inspection of girth welds during construction of long-distance pipelines, both on- and offshore. It is characterized by high inspection speed and instant recording of results. Unlike prevailing radiography, it provides immediate feedback to the welders.

Recent technical improvements in flaw sizing and recording have allowed the application of rejection/acceptance criteria for weld defects based on fracture mechanics principles. The development and actual use of such modern acceptance criteria, particularly in Canada, supported the introduction of mechanised ultrasonic inspection. World wide applications proved that, contrary to expectations, ultrasonic inspection does not lead to higher weld repair rates than radiography does. Between early 1989 and now, over 5.000 km of pipeline (300.000 welds) were inspected with Rotoscan and its reliability proven.

The introduction of colour enhanced transit distance “C-scan mapping”, producing a coherent picture based on the signal’s transit distance, enabled the system to cope with most existing ultrasonic procedures and acceptance criteria, because of its capability to detect and quantify volumetric defects. Moreover, the integrated simultaneous Time Of Flight Diffraction (TOFD) function enables through-thickness sizing of defect. The present system is capable of achieving a high Probability Of Detection (POD) together with a low False Call Rate (FCR).

In the meantime, Rotoscan has been qualified in various countries, for different customers and for a variety of weld processes, pipe diameters and wall thicknesses. Because of its features, the now mature system has demonstrated its capabilities also for use on lay barges as an alternative to high-speed radiography.
Customized Ultrasonic Systems for Gas Pipeline Girth Weld Inspections
Authors: Moles Michael D. C. , Dubé Noël , Ginzel Ed A.
Published: October 2016

Gas pipeline ultrasonic inspection girth weld systems have been well established for typical Canadian conditions, primarily through the efforts of TCPL and NOVA. However, the specific weld profiles, wall thickness, environment and operating conditions found in Canada do not necessarily represent girth weld inspections elsewhere. This paper describes some different inspection conditions, and some of the possible solutions, which may or may not have been implemented to date. For example, the extreme Canadian weather may require heating transducer wedges, or using dummy wedges to measure temperature. Sandy or salty conditions may require different designs and materials. Different weld profiles will require different ultrasonic set-ups, as will different inspection specifications. For flexibility, it is possible to design expandable inspection heads with replaceable probe modules, and to include extra ultrasonic transducers for TOFD or additional scans. Tight time constraints can lead to quick-release levers for speedy head changes, as well as modular, replaceable components. Since the operator is critical in the inspection, a number of software additions can be added to speed inspection, interpretation and set-up. For example, defect locations can be automatically displayed on the weld profile to aid interpretation. A table of defects can be shown so the operator can click on a selected defect to automatically display the appropriate scan region. Defects can be analyzed automatically by length and amplitude to determine accept/reject. Calibration set-up for a particular transducer can be recalled simply by clicking on the appropriate zone in the weld display. Automated recording and acceptance of calibration scans can be performed.
Pipeline Design and Construction Using Higher Strength Steels
Authors: Glover Alan G. , Horsley David J. , Dorling David V.
Published: October 2016

Grade 550 (X80) pipeline steels are now the basis of a standard platform for the design and construction of large-diameter pipeline projects at NOVA Gas Transmission (NGT). Their introduction in 1995 and further application in 1997 have provided material savings, provided greater gas flow capacity and fuel gas savings and, once again, shown NGT to be an industry leader in successfully developing and applying new technology in response to business needs. The paper will outline the development of a Canadian capability to supply these steels, discuss design aspects including fracture initiation and arrest and weld/pipe strength mismatch, the overall cost efficient approach to material and weld requirements, and pipeline construction using mechanized welding with mechanized ultrasonic inspection and alternative weld acceptance standards. Future directions at NGT with respect to higher strength steels will also be described.
Quality and Productivity Improvements in the Field Welding of High Strength Thin Walled Pipelines
Authors: Barbaro Frank J. , Henderson Ian D. , Dunne Druce P. , Painter Michael J. , Norrish John , Harrison Robert P.
Published: October 2016

During the past 20 years the Australian Pipeline Industry has achieved significant economic improvements in the design and construction of natural gas transmission pipeline networks. This improvement is based on the use of thin walled high strength high pressure pipelines which serve relatively small markets separated by long distances from gas reserves.

The Industry in conjunction with the WTIA/APIA Research Panel 7 and the Cooperative Research Centre for Materials Welding & Joining, have developed a research program with a number of key deliverables which aim to improve the overall economics of pipeline design, construction, inspection and maintenance activities by providing the level of assurance necessary to confidently build reliable pipelines using high strength linepipe including X80 grade.

This paper details recent developments in the Australian Pipeline Industry and the coordinated research and development program to advance the economic use of high strength pipeline technology under Australian conditions.
An Investigation of the Factors Influencing the Formation of Hollow Bead Pores in Pipeline Girth Welds
Authors: Cantin Gersende M. Delphine , Bee John V.
Published: October 2016

Hollow bead is an elongated linear pore aligned with the weld axis. The sporadic appearance of epidemics of hollow bead defects during the construction of pipelines has for years been responsible for increasing the cost and time required for completion of a number of projects in many parts of the world. The inability to identify the cause of this defect has been one of the major obstacles in attempting to reduce its occurrence. As a result of this situation, following an important pipeline construction project which was seriously disrupted by problems with hollow bead, a number of Australian companies contributed to a major three year programme of research undertaken by the Cooperative Research Centre for Materials Welding and Joining. A systematic study of the effects of a range of parameters including welding variables, parent metal composition, joint geometry, surface condition and welding consumables has been undertaken. The data obtained has been used to ascertain their influence on the occurrence of hollow bead pores, and to provide guidelines for field welding practice which provide a high level of confidence that hollow bead can be eliminated as a practical problem in pipeline construction.
Material Assessment of Canadian SAW Line-Pipes
Authors: Mak D. K. , Tyson W. R.
Published: October 2016

Eight pipes, manufactured between 1952 and 1981, have been collected from various Canadian pipeline companies and tested. They include six pipes from the field made in the 1950’s and 1960’s of X52 grade, one experimental pipe manufactured in the early 1970’s of X65 grade, and a modern clean steel of X70 grade manufactured in 1981. The steels have been characterized by chemical composition, grain size, yield and tensile strengths, notch toughness (Charpy V-notch absorbed energy), and fracture toughness (J-integral and crack-tip opening displacement). The modern steel has much lower carbon content and much smaller grain size compared to the pipes manufactured in the 1950’s and 1960’s. The former is a fully-killed controlled-rolled steel while the latter are semi-killed ferrite-pearlite steels.

All eight pipes have ferrite-pearlite microstructures, with the average grain size ranging from 4 to 14 μm. The transverse yield strength was found to be significantly higher (by about 20%) than the longitudinal yield strength. Notch toughness and fracture toughness were similar for pipes manufactured in the 1950’s and 1960’s. In comparison, the modern steel has much higher toughness and higher strength.

J-integral and CTOD δ were found to be related by J = m σyδ with m = 1.8 and σy the transverse yield strength. The J-integral at 0.2 mm crack growth was consistent with a linear correlation with the upper-shelf Charpy energy. All the steels in this study fractured by ductile tearing in slow loading in spite of the low toughness of the older steels. It is suggested that, in the absence of Charpy upper shelf data, a reasonable representative toughness for resistance to axial surface flaws propagating by ductile tearing is J = 120±15 kJ/m2.
Seismic Hazard Assessment and Remediation of Pipelines
Authors: Fitzell Trevor P. , Wijewickreme Dharma K.
Published: October 2016

The performance of pipeline systems under seismic loading is an important consideration in regions subject to earthquakes. This paper briefly describes a study to evaluate the vulnerability of a natural gas transmission system to seismic hazards, along with some of the remedial treatment options which are being considered. The study was carried out for BC Gas Utility Ltd. in the Greater Vancouver Region of British Columbia. The results of the study are being used by BC Gas in emergency response planning and remedial treatment activities to limit their risk exposure.

The paper describes the approach used to assess liquefaction and lateral spreading risks, and remedial treatment options which were considered. This involved generation of design seismic ground motions, seismic hazard mapping, geotechnical investigations to determine the subsurface conditions, and geotechnical and structural numerical modeling and analysis to assess pipeline performance and remedial treatment options.

Several different approaches to remediation are described; one involves ground treatment to reduce the risk of unacceptable ground deformations; another involves structural modifications to improve the resistance of the pipeline to seismic motions, while another makes use of directional drilling to re-align the pipe below infirm areas.
Analysis of Stresses on Buried Natural Gas Pipeline Subjected to Ground Subsidence
Authors: Kim Hyoung-Sik , Kim Woo-Sik , Bang In-Wan , Oh Kyu Hwan
Published: October 2016

This study was initiated to examine the stress and deformation characteristics of the pipelines which were subjected to various environmental conditions in order to confirm their integrity. As the part of them, this paper presents the analysis results for the effect of ground subsidence combined with main loads on buried natural gas pipelines. The ground subsidence which can occur for buried gas pipeline has been classified to the three cases.

Finite element method was used to analyze the effect of ground subsidence on pipeline of 26 inch (0.660 m) and 30 inch (0.762 m) diameter used as high pressure (70 Kgf/cm2(686.4 Pascal)) main pipelines.

This paper shows the result of stress analysis for the pipelines subjected to those three case ground subsidence. Comparing these results with safety criterion of KOGAS (0.9 σ y), maximum allowable settlement and loads have been calculated.
In-Situ Evaluation of Pipeline Bedding and Padding Spring Constants
Authors: Tart Rupert G. , Hughes John M. O.
Published: October 2016

Structural response analyses of pipelines using computer models, such as AutoPIPE, incorporate soil “springs” to model the restraint provided by pipeline bedding and padding. These “springs” are referred to as spring constants and are most frequently determined from a limited number of sources in the literature. In some cases representative soil properties are used with theoretical and empirical formulae such as those presented by Nyman (1984). This technique which is referred to herein as the ASCE technique has been used by Alyeska Pipeline Service Company (Alyeska) engineers in their calculations of structural response of the buried pipeline along the Trans Alaska Pipeline System (TAPS) (Hart et al, 1998).

This paper describes a field study at a pipeline inspection dig in which spring constants were determined directly from a series of field tests to develop a better understanding of the pipeline restraint the bedding and padding is providing for the pipe. Four other papers which cover other aspects of the work performed at this site are also a part of this conference (Hart et al, 1998, Norton et al, 1998, Stevick et al, 1998, Tonkins et al, 1998).

The field work included the drilling of multiple boreholes in which drive samples were taken at about 1 to 2 meter (3 to 5 foot) intervals. In each borehole, pressuremeter tests were also conducted at the same intervals as the drive samples. At two levels in the open pipe trench plate, load tests were conducted. Both nuclear and sand cone density tests were made at several levels in the pipe trench.

Results of these tests were correlated to each other. Stress strain relationships were developed from the pressuremeter test and plate load test data which were used independently to develop spring constants. Spring constants were found to vary with the strain level in the soils and were correlated to the drive sample blow count data. Recommended methods for estimating spring constants are presented.
Incorporating Muskeg Soil Shear Strength Into Buoyancy Control Design
Authors: Simmonds Gordon R. , Thomas Lance N.
Published: October 2016

For the past four years, NOVA Gas Transmission Ltd. (NGTL) has included the backfill shear strength in buoyancy control design for natural gas pipelines built and operated in muskeg soil laden terrain. Incorporation of muskeg soil shear strength has resulted in major cost reductions. In typical muskeg soil laden terrain, the weighting requirement for NPS 4 and smaller pipelines has been eliminated, while the need for weighting of larger pipelines has been significantly reduced.

Traditionally, muskeg soil shear strength has not been considered due to an absence of adequate theoretical and performance data. NGTL has constructed a series of laboratory and field studies in an attempt to quantify the contribution of “muskeg soil shear strength.” The results of this research program, when combined with a rudimentary field investigation, are part of NGTL’s current buoyancy control design methodology for pipelines traversing muskeg soil laden terrain.

This paper presents a practical methodology used by NGTL for buoyancy control. Design examples are provided to calculate two design components; the maximum tolerable muskeg depth and optimum weight spacing. The paper concludes with a discussion of construction and operational considerations which influence buoyancy control design.
Determination of Pipe Roughness and Heat Transfer Coefficient in Pipeline Networks Using Multidomain Solution Method
Authors: Jelen Jaroslaw , Golshan Hossein , Rizopoulos Sandy
Published: October 2016

In the development of new pipeline projects, all too often assumptions that are made in the initial stages of the business development opportunity are, for the most part, overly conservative. This inaccuracy is carried out through to the operation of the pipeline system and most assumptions do not change with subsequent expansions in the future until a conscious effort is made to determine and monitor those significant parameters that impact the pipeline’s overall performance.

In highly complex systems such as NOVA Gas Transmission Ltd.’s (NGTL’s) pipeline network, with over 21400 Km of pipe segments of different sizes and ages, for an accurate determination of pressure drop while 12 BCF of gas, on average, is flowing through our network, we need a technique to precisely assess the values of friction factor and heat transfer coefficient. These values have a profound impact on the accuracy of the hydraulic simulations.

The calculated values of pressure, flow rate, and temperature may be distorted by imprecise values of some parameters, such as friction factor or heat transfer coefficient. Thus, a proper estimation of these parameters is of great importance to the successful numerical flow simulation. Both friction factor and heat transfer coefficient are very difficult to measure; therefore, their values can only be assessed by solving an inverse problem (i.e. parameter identification process).

Since the parameter estimation procedure reported in this paper requires multiple solution of inviscid gasdynamics differential equations, describing the gas flow through the pipeline system, a multidomain solution method has been applied to effectively solve the parameter identification problem.
Pipeline Fault Diagnosis System Enhancement
Authors: Xiujia Tang
Published: October 2016

In order to decrease the false alarm rate and improve the sensitivity of pipeline fault diagnosis system, three artificial intelligence based methods are first proposed. Neural networks with the input matrix composed by stress wave characteristics in time domain or frequency domain is proposed to classify various situations of the pipeline, in order to detect the leakage from pipeline online running data. Context-free grammar of symbolic representation of the negative wave form is used and a negative wave form parsing system with application to syntactic pattern recognition based on the representation is described. New complex thermal and hydraulic models, in which the flow regime, viscosity-temperature characteristics, density-temperature characteristics and specific heat-temperature characteristics, etc., of the running fluid in the pipelines are set up for non-isothermal pipeline carrying higher temperature fluid or in ambient environment.
Improved Leak Detection by Method Diversity
Authors: Pichler Ruprecht M. J.
Published: October 2016

Leak detection systems for liquid pipelines are installed to minimize spillage in case of a leak. Therefore reliability, sensitivity and detection time under practical operating conditions are the most important parameters of a leak detection system. Noise factors to be considered among others are unknown fluid property data, friction factor, instrument errors, transient flow, slack-line operation and SCADA update time. The opening characteristics and the size of leaks differ considerably from case to case.

Each software-based leak detection method available today has its particular strength. As long as just one or two of these methods are applied to a pipeline a compromise has to be found for the key parameters of the leak detection system.

The paper proposed illustrates how a combination of several different software-based leak detection methods together with observer-type system identification and a knowledge-based evaluation can improve leak detection. Special focus is given to leak detection and automated leak locating under transient flow conditions. Practical results are shown for a crude oil pipeline and a product pipeline.
Application of CFD to the Design of Multirun Meter Station With Ultrasonic Meters
Authors: Jelen Jaroslaw , Studzinski Wojciech , Brown Michael
Published: October 2016

Designers of ultrasonic meter stations with headers do not have any experimental data which can help to determine proper location of the multipath ultrasonic meter within the meter run. The results of meter tests are limited to such configurations as a single 90° elbows and two elbows out of plane. Because of the variety of header layouts used in practice any experimental information related to this piping configuration will be of limited use in the design process.

The proposed approach is based on the application of Computational Fluid Dynamics (CFD) methods to the evaluation of header effects on ultrasonic flow meter using a commercial CFD code combined with a numerical model of the ultrasonic meter.

The numerical simulation of the flow field in the header and meter runs and subsequent integration of the obtained velocity field in a numerical model of multipath ultrasonic meter were used to determine the optimal meter position. This approach was validated against available experimental data on the ultrasonic meter performance downstream of single and double elbow. The comparison of simulations and test data has shown very good agreement of trends exhibited by the meter. The trends were replicated by the simulator within approximately 1% for X/D ≥5 and within 0.5% for X/D ≥9.
Pipeline Operations Training Using a Pipeline Simulator
Authors: Sutherland Dale , Lehmann Wolfgang
Published: October 2016

This paper details the authors’ experiences in using a pipeline simulator in pipeline operations training programs.

Pipeline simulators allow trainees to practice basic and advanced operating techniques in a “safe” environment. In the early stages of applied operator training, the simulator usually represents a fairly simple, generic pipeline. This allows clear illustration of operational concepts with a focus on specific tasks. In more advanced stages of an operator’s training cycle, the simulator can provide an exact simulation of the pipeline that the trainee will have to control in the future. Realistic scenarios can be presented and operator trainees are able to exercise almost all tasks and deal with any possible incident that may occur during the operation of a pipeline. Accurate records detailing trainees’ operational decisions during a simulator exercise are maintained and help in determining the skill level of different trainees. This information allows pinpointing of specific areas where more training may be needed.

At the same time, pipeline operations training which uses a simulator can address certification requirements. A simulator allows a company to set standards, and then to test operational skills and knowledge against those standards in a quantifiable and controllable manner. Since the performance of a trainee during a simulator training session is fully recorded, companies can use this record as a measure when qualifying operators.
Exploring the Potential for Constructivist Learning Theory in SCADA Domains
Authors: Cox Lynne , Jackson Craig
Published: October 2016

SCADA software training is undergoing a remodeling of technical training courseware to incorporate new cognitive learning approaches. In order to better facilitate the learning requirements of our customers’ knowledge domains, Valmet technical trainers are looking at ways to infuse concepts from cognitive science, constructivism and the models of andragogy into their training materials. This paper synthesizes the research undertaken by Valmet trainers towards building a training model for the delivery of future courseware. A pilot Train the Trainer course, aimed at helping intermediate to advanced learners acquire knowledge and hone problem-solving skills, has been created as a result of our research.
Development and Implementation of the NOVA Gas Transmission Ltd. Conservation and Reclamation Standard
Authors: Nixon Jeannette K. , Etherington Karen L.
Published: October 2016

Currently, under Alberta’s Environmental Protection and Enhancement Act and regulations, all pipelines transporting natural gas with an index of 2690 or greater require an approval (Conservation and Reclamation Approval) for the conservation and reclamation activities associated with construction and reclamation of a pipeline. Administratively, Alberta Environmental Protection considers a pipeline requiring an Environmental Protection and Enhancement Act approval as a “Class 1” pipeline. The index is a calculation of length of pipe (in kilometers) multiplied by the outside pipe diameter (in millimeters).

NOVA Gas Transmission Ltd. (NGTL) has developed and implemented a Conservation & Reclamation (C&R) Standard to streamline the provincial C&R Application process. By re-formatting the currently accepted C&R Application into a Standard document, textual information submitted for an individual project has been reduced, without affecting the quality of environmental planning.

The Standard document compiles NGTL’s environmental standard practices and mitigative measures undertaken for all pipelines. It also explains NGTL’s decision-making processes during the design phase of a project.

The project-specific document presents issue focused site-specific environmental details in a simplified format The C&R Standard in combination with the project-specific submission form the NGTL C&R Application.

NGTL’s C&R Standard was developed within a concept which uses key building blocks to achieve industry accountability. This concept requires an organization to have performance measurement tools in place, and to demonstrate commitment to that performance in order to earn public confidence. Once this confidence is established and maintained, an organization can realize industry accountability. Considering this concept, NGTL leveraged past performance and experience by documenting our consistent approach to pipeline design, and our performance measurement criteria into the C&R Standard.

Fundamental to the development of the Standard was NGTL’s Platform Design Concept. Initially this design concept was adopted as an integral component of NGTL’s business need to reduce and streamline internal processes. This concept was then applied to external processes in an effort to meet business needs.

The Standard includes two primary components, Guiding Principles and Platforms. By combining NGTL Guiding Principles (‘What’ and ‘Why’) and NGTL Platforms (‘How’), the Concept provides a systematic design guide for all projects that allows NGTL to make the right decisions based on the right design criteria.

NGTL submitted the C&R Standard document to Alberta Environmental Protection for review in July 1997 and is currently implementing the Standard for all C&R Applications. This paper describes the development of the document as well as the implementation process and experience of the Standard.
Environmental Management for Regulated Industrial Wastes
Authors: Loven Larry
Published: October 2016

This paper is to keep you informed of certain recent developments in the Alberta Energy and Utilities Board (AEUB) that is of particular interest to pipleline companies. Since these changes were first initiated, the Board has undertaken a significant transformation of the management of regulated wastes from the petroleum industry.

The passing of the G-58 guidelines will have far reaching effects on the business environment of the petroleum industry.

We have analyzed some of the more important aspects of this reform.

We continue to closely monitor changes from our western Canadian operations, particularly the impact of those changes on those generating regulated wastes in Alberta.
Response, Remediation and Risk Management of a Crude Oil Pipeline Spill
Authors: Doupe J. T. , Livingstone W. R.
Published: October 2016

In December 1995, an oil spill was discovered along a section of pipeline located near the bank of a major river, less than 1 km upstream of the water supply intake of a southern Alberta community. The spill, which involved light crude oil, was observed at ground surface over an area of approximately 3 000 m2 at the top of the river slope and had also migrated downslope through the subgrade soils and along the groundwater table toward the river.

The initial emergency response activities consisted of removing and disposing of oil-stained vegetation and snow, and the containment and recovery of free oil pooled on ground surface. Subsequent subsurface assessments involved the drilling of test holes and boreholes, and installation of groundwater monitoring/recovery wells. Based on the results of these assessments, a remedial action plan was developed. As part of this plan, some of the impacted soils were excavated and placed in lined treatment cells for bioremediation. The limits of the excavation were based on field screening measurements and on soil clean-up criteria developed through an assessment of the human health risk and ecological impacts.

Investigations conducted at the site also indicated that phase-separated crude oil had migrated further downslope and had accumulated at the water table within the flood plain sediments adjacent to the river. Therefore, remediation systems were installed to recover the oil, recover and treat the impacted groundwater, and prevent further migration of the impacted groundwater and oil toward the river. Impacted groundwater recovered from the flood plain deposits was treated onsite and was then injected back into the flood plain deposits via an infiltration gallery. The performance of the pumping and remediation systems was monitored regularly and water samples were recovered from the treatment system, selected monitoring wells and the river. Based on the results of these analyses, the quality of local groundwater steadily improved and the zone of impacted water was effectively contained.
Impacts and Recovery in a Coldwater Stream Following a Natural Gas Pipeline Crossing Installation
Authors: Anderson Paul G. , Fraikin Christian G. J. , Chandler Trevor J.
Published: October 2016

Findlay Creek is a small, coldwater stream which was crossed by a natural gas pipeline using conventional open-cut techniques in late August 1992. Pipeline crossing activities included the removal of a beaver dam which was located along the proposed alignment, the installation of a temporary road crossing, and the actual pipeline installation. A monitoring study was initiated to examine the impacts of pipeline construction on this stream including changes in the physical and biological regimes of the aquatic ecosystem. Results of this study indicate that the dramatic sediment loads (suspended sediment levels of up to 3000 mg/L) caused by pipeline construction were sufficient to cause changes to the channel morphology as well as the fish and invertebrate communities. By twelve weeks post-construction, partial recovery of habitats and aquatic communities was apparent. Changes to the physical channel parameters and the stream population structure documented in this study suggest that impacts to Findlay Creek were localized, and full recovery was documented in affected areas by the one year post construction sampling period. This study concurs with other research investigating the impacts of pipeline construction, in that impacts on the aquatic fauna appear to be localized in extent and short term in duration.