bluuebunny/crossref_metadata_2025 huggingface dataset:
A Discussion on How Internal Pressure is Treated in Offshore Pipeline Design
Authors: Galgoul Nelson Szilard , Lupinacci Massa Andre´ Luiz , Claro Cla´udia Albergaria
Published: December 2008

The design of rigid submarine pipelines has been the object of extensive research work over the last few years, where the most relevant issues include upheaval and lateral buckling problems. Both of these problems systematically associate temperature and pressure loads, where the treatment of the first is obvious, while the latter have always been a matter of discussion. In 1974 Palmer and Baldry [1] presented a theoretical-experimental contribution, in which they have set a pattern that has been followed ever since. Another similar and well known paper was published by Sparks in 1983 [7], who only present a physical interpretation of this same theory. Most of the present day industry codes define an effective axial force, according to which, fixed end pipelines will be under compression due to internal pressure. The starting point of the discussion presented in [1] was that internal pressure produces a lateral force, which is numerically equal to the pressure times internal cross-sectional area times the pipeline curvature: q=p.Ai.d2y/dx2(1) This equation is demonstrated further ahead in this paper. Palmer and Baldry then based their arguments on the traditional equation of the pinned column buckling problem, studied by Euler [2]: EId4y/dx4+Pd2y/dx2=0(2) for which the well known solution is: P=π2EI/L2(3) and on the associated problem studied by Timoshenko [3], which adds a distributed lateral load q to the same problem: EId4y/dx4+Pd2y/dx2=q(4) Replacing q with the lateral pressure given above, they were able to have their own problem fall back onto the Euler solution: EId4y/dx4+Pd2y/dx2=p.Ai.d2y/dx2P-pAi=π2EI/L2(5) After correcting for the Poisson effect they were able to determine the new critical axial force caused by the pressure. Unfortunately, however, the arguments set forth in [1] have been misunderstood. The fact that both axial force and lateral force multiply curvature does not make them forces of the same nature. Being able to add them has solved a mathematical equation, but still hasn’t converted the lateral force to axial. The authors wish to prove that [1] presents no more than a tool, which can be used in the analysis of global buckling problems of pipelines subject to both temperature and pressure. It will be shown, however, that this pressure will not produce an axial force, as now-a-days prescribed conservatively in many pipeline codes, which is even used for stress checking.
A Streamlined Approach for Pipeline Integrity Management
Authors: Porter Todd R. , Marr James E.
Published: December 2008

Formulating and implementing an integrity management plan (IMP) that satisfies Regulatory compliance requirements as mandated in the United States Department of Transportation (US-DOT, CFR 192 / 195) is a significant undertaking. The initial implementation step as defined in the regulations, is to identify high consequence areas (HCA’s or “covered segments”, and the integrity threats that could potentially impact the pipeline. These threats drive the data requirements, i.e. the minimal data sets required to address and evaluate these threats. This data must be gathered, aligned, integrated and technically analyzed (i.e. use of threat models) in a consistent and systematic manner. A baseline / risk assessment is then conducted using this data with the integrity threat models — to identify potentially higher risk areas within a system, individual lines, pipe segments, joints or specific points on the pipelines. The pipeline analysis normally includes time dependent, time independent and stable threats. Integrity management decisions are made based on the outcome of this initial assessment. This leads to selection of integrity assessment tools such as In Line Inspection (ILI) technologies, Direct Assessment (DA), Hydro Static testing, other methods, or combinations thereof. The outcome of the integrity assessment is used to develop an optimal, prioritized repair & mitigation program. In both regulated and non-regulated environments, there is critical need to prioritize and address immediate and near term repair situations a tactical approach. In order to effectively implement an IMP, a management system is normally required that captures the work process of the integrity team and delivers rapid, accurate, and economic decision support. Efficiencies can be realized with a well coordinated approach to data acquisition, management, and analysis. Tuboscope provides an integrated pipeline solution (TIPS) approach to streamline these processes, and an Integrity Management Vehicle LinaViewPRO™, to manage, analyze and present the results of the integrity analysis. In the quest for regulatory compliance and subsequent maintenance of the line, this paper will present an integrity process overview, implementation, results, and benefits from operating hazardous liquid and gas transmission pipelines integrity projects.
Integrating Automated Ball Indentation With ASME B31G Code to Assess Integrity of Corroded Pipelines
Authors: Haggag Fahmy M. , Phillips Larry D.
Published: December 2008

In order to provide deterministic structural integrity assessment for safe and efficient operation of corroded pipelines, the following information is required: (a) the actual key mechanical properties (yield and ultimate strength, and fracture toughness) of the pipeline materials, (b) the present thickness and diameter of the pipeline, and (c) the profile of the maximum depth of corrosion pits over the pipeline axial length, and the size of sharp cracks. Both items (b) & (c) can be determined by conventional techniques. A patented in-situ Stress-Strain Microprobe (SSM) system was used to provide item (a), the required key mechanical properties (tensile and fracture toughness), in a nondestructive and localized fashion without any interruption of the pipeline transmission using its novel Automated Ball Indentation (ABI) test technique. The SSM system was used on a short segment of a 356-mm (14-inch) diameter Kerosene pipeline. Although there was no documentation of the pipeline steel grade, the minimum ABI-measured yield strength at four locations was 277 MPa (40.2 ksi) and the minimum ultimate tensile strength was 378 MPa (54.8 ksi) indicating that the steel met the requirements of Grade “A”. Both the Rstreng software and the ASME B31G code were used to calculate the maximum safe operating pressure for the corroded pipeline. The calculations showed that a profile with a few corrosion pits [3–6 mm (0.075–0.236 inch) maximum depth spaced over 483 mm (19 inches) length] reduced the maximum safe pressure significantly from 4.24 MPa (615 psi) to 0.74 MPa (107 psi). The operator of the pipeline limited the maximum operating pressure to 0.69 MPa (100 psi). Furthermore, it was recommended that the ABI measurements be performed on at least 10% of the 7-km Kerosene pipeline and on all patches and welds in order to provide the minimum yield strength values required for determining the remaining strength of the pipeline. This work proves that the integration of the ABI measurements with the corrosion pitting profile allows calculation of the maximum safe operating pressure in order to make the appropriate decision of replacement or repair of certain pipeline sections.
SCC Detection and Mitigation Based on In-Line Inspection Tools
Authors: Kresic Walter , Ironside Scott
Published: December 2008

The focus of the Enbridge Integrity Management System is to prevent leaks or ruptures caused by all duty-related pipe deterioration including SCC. As with all pipe defect types, ongoing monitoring programs are employed to determine whether SCC has occurred. Where it has, preventative maintenance programs are employed to mitigate the SCC. Where required, Enbridge employs high-resolution crack in-line inspection (ILI) as the most precise method for managing SCC. As a member of the Canadian Energy Pipeline Association (CEPA), Enbridge participated in the development of a basic framework for SCC management programs and has adopted this framework as the basis for the Enbridge program. Ultrasonic crack detection ILI, capable of detecting SCC, has been employed on over 3000 km of Enbridge pipe and several hundred investigative excavations have been conducted in relation to the ILI data. The results gathered from these investigations have been trended to define the effectiveness of crack detection ILI to detect, size, and discriminate SCC defects. This paper and presentation describes Enbridge’s experience utilizing ultrasonic crack detection ILI for SCC management. The Enbridge trends have shown that ILI can be reliably utilized to detect SCC but, additional innovation is required for defect sizing. While ILI sizing is limited, trends developed from field inspection data have provided the ability to categorize ILI signals into general classifications that ensure all relevant SCC features are highlighted. The categorization is accurate but added precision would reduce the number of investigative excavations, which currently, are also conducted on many sub-relevant features. Coincident with SCC activities driven by ILI data, trends were also developed for peripheral aspects such as field NDT technology, fitness-for-purpose equations, and SCC initiation and growth causes. Observations and trends related to these activities are also described herein.
Metrology in Bolivia-Brazil Gas Pipeline
Authors: Palhares Julio Cesar
Published: December 2008

The measurement guidelines of Transportadora Brasileira Gasoduto Boli´via-Brasil – TBG, are intended to be ever-assisting to the client’s needs and in line with natural gas market changes. In five years of corporative organization TBG has been familiar with the legislation of regulatory agencies as well as the institution of the contract inspector, which are important benchmarks in market progress. This paper presents the definitions that routed TBG’s metrological course of action, which aims at satisfying its own needs plus the needs of its clients, as well as complying with the legislation requirements by using suitable tools in the response to each specific demand. The work embodies the calibration procedures, the qualification of suppliers, the upkeep of metrological reliability, daily totalization of the delivered volumes, failure treatment, as well as monitoring of unaccounted for gas and control thereof, all in line with the precise limits as accepted abroad.
Multi-Objective Optimization of Large Pipeline Networks Using Genetic Algorithm
Authors: Botros K. K. , Sennhauser D. , Jungowski K. J. , Poissant G. , Golshan H. , Stoffregen J.
Published: December 2008

This paper presents application of Genetic Algorithm (GA) methodologies to multi-objective optimization of two complex gas pipeline networks to achieve specific operational objectives. The first network contains 10 compressor stations resulting in 20 decision variables and an optimization space of 6.3 × 1029 cases. The second system contains 25 compressor stations resulting in 54 decision variables and an optimization space of 1.85 × 1078 cases. Compressor stations generally included multiple unit sites, where the compressor characteristics of each unit is taken into account constraining the solution by the surge and stonewall limits, maximum and minimum speeds and maximum power available. A key challenge to the optimization of such large systems is the number of constraints and associated penalty functions, selection of the GA operators such as crossover, mutation, selection criteria and elitism, as well as the population size and number of generations. The paper discusses the approach taken to arrive at optimal values for these parameters for large gas pipeline networks. Examples for two-objective optimizations, referred to as Pareto fronts, include maximum throughput and minimum fuel, as well as, minimum linepack and maximum throughput in typical linepack/throughput/fuel envelopes.
Optimization of Pump Energy Consumption in Oil Pipelines
Authors: Barreto Claudio Veloso , Pires Luis Fernando Gonc¸alves , Azevedo Luis Fernando Alzuguir
Published: December 2008

In the present work an optimization study was conducted with the objective of providing pipeline operators with a simple, spreadsheet-based computational tool to help decrease the electrical energy consumption associated with a particular transport operation. The methodology proposed encompasses the construction of a database of information on the pipeline regarding pumping power consumption, for all possible pumping arrangements and flow rate ranges considered viable for the pipeline. This database is fed to a spreadsheet programmed to calculate the minimum pumping cost for a particular operation. This calculation takes into account, the volume of product to be transported, start and finish times, fluid properties, and the possibility of the existence of a low and a high electricity tariff based on geographical location and time of the day. The methodology was applied to the ORBEL II pipeline in Brazil, and two case studies were conducted. Significant cost savings were obtained by the use of the methodology developed.
In-Service Pipeline Non Destructive Examination Technology Applications
Authors: Dawe Shaun
Published: December 2008

Enbridge operates the longest and most complex crude oil and liquids pipeline in the world. Enbridge Pipeline systems have operated for over 50 years and comprise approximately 15,000 kilometers (9,000 miles) of pipeline, delivering more than 2 million barrels per day of crude oil and liquids. A variety of in-service non-destructive examination (NDE) processes are available to pipeline operators to inspect for internal corrosion, external corrosion and cracks. Enbridge Pipelines have completed over 2000 excavations of in-line inspection (ILI) tool-identified defects in the past several years. Enbridge has tested and utilized various NDE techniques to assess these defects with varying degrees of success. This paper identifies how Enbridge has employed a selection of automated internal and external corrosion mapping systems and advanced ultrasonic flaw sizing techniques. The review of these processes and techniques states the author’s views of the benefits, drawbacks and application nuances.
Pressure Reductions and Pipeline Excavation
Authors: Coote Robert I. , Keith J. Kyle
Published: December 2008

Pipeline companies often reduce the pressure while performing maintenance activities and integrity excavations on in-service pipelines. Despite this practice, pipeline design codes, regulations and industry publications offer little guidance on what factors should be considered to determine how much, if any, the pressure should be reduced from operating levels during excavation activities. Also, it is not commonly understood what level of safety is introduced with these reductions and what historical operating pressure level should be used as the basis for the reductions. A literature survey and an interview process with CEPA member companies summarized common industry practices and determined factors to be considered when assessing if and how much of a pressure reduction is appropriate while excavating an operating energy pipeline.
Innovative PLC Design Concepts for Petroleum Pipeline and Terminal System
Authors: Rivera Arnold L. , Day Darren C.
Published: December 2008

Enbridge Inc. operates the world’s longest crude oil and refined liquids pipeline system. The company owns and operates Enbridge Pipelines Inc. (the Canadian portion of the Enbridge crude oil mainline) and a variety of affiliated pipelines in Canada and the United States. It also has approximately, a 12% interest in Enbridge Energy Partners, L.P. which owns the Lakehead Pipeline System in the United States. These pipeline systems have operated for over 50 years and now comprise approximately 15,000 kilometers (9,000 miles) of pipeline, delivering more than 2.2 million barrels per day of crude oil and refined liquids. The combination of the Enbridge System in Canada and the Lakehead System in the United States brings together the primary transporter of crude oil from Canada into the United States. It is also the only pipeline that transports crude oil from Western Canada to Eastern North America, serving all of the major refining centres in the province of Ontario as well as the Great Lakes region of the United States. The system consists of approximately 9000 kilometers (5,600 miles) of mainline pipe in Canada, and 5300 kilometers (3,300 miles) of mainline pipe in the United States. The Canadian portion of the pipeline system extends from Edmonton, Alberta as the primary initiating facility, across the Canadian prairies to the U.S. border near Gretna, Manitoba. It continues again from the U.S. border near Sarnia, Ontario, to Toronto, Ontario, and Montreal, Quebec, with lateral lines to Nanticoke, Ontario, and Niagara Falls, Ontario. The total length of the pipeline right-of-way is nearly 2300 kilometers (1,400 miles).
Managing Integrity of Submarine Gas Pipeline Based on the Application of ASME B31.8-S Standard
Authors: Wisianto Arie
Published: December 2008

Managing pipeline by implementing Pipeline Integrity Management (PIM) for both onshore and offshore pipeline now has been done by several operators because they had realized its benefit. Especially for offshore / submarine pipeline we have not yet found an appropriate guideline / recommended practice which can assist us to develop PIM system. After evaluating some guideline we were surprised by ASME B31.8S a PIM standard addressed for onshore pipeline, but we think this standard can be adopted and applied for submarine pipeline. According to our opinion this standard contains technical and non technical aspect, a structured methodology which can assist operator to develop PIM comprehensively. We bring our case of developing PIM for submarine pipeline using ASME B31.8-S, starting from data gathering, identification potential hazard, risk assessment, survey, engineering analysis and the result is rectification program as first priority for our inspection, maintenance and repair (IMR). Based on our experience, this standard is suitable for us when developing PIM program and conducting remedial work as part of IMR program although some notes are being taken.
Special Phased Array Applications for Pipeline Girth Weld Inspections
Authors: Moles Michael , Dube´ Noe¨l , Labbe´ Simon
Published: December 2008

Ultrasonic phased arrays present major improvements over conventional multiprobe ultrasonics for inspecting pipeline girth welds, both for onshore and for offshore use. Probe pans are lighter and smaller, permitting less cutback; scans are quicker due to the smaller probe pan; phased arrays are considerably more flexible for changes in pipe dimensions or weld profiles, and for different scan patterns. More important, some of the potential advantages of phased arrays are now becoming commercially available. These include: compensating for variations in seamless pipe wall thickness; wedge temperature compensation; premium inspections for risers, tendons and other components; small diameter pipes; multiple displays; clad pipe; portable phased arrays for tie-ins and repairs; improved sizing approaches. The paper will describe the latest phased array UT results for special applications.
The Significance of Low Toughness Areas in the Seam Weld of Linepipe
Authors: Andrews Robert M. , Morgan Glyn C. , Beattie W. Jack
Published: December 2008

There are concerns that there may be areas of low toughness in the seam welds of submerged are welded linepipe. These areas are typically associated with the Coarse Grained Heat Affected Zone and manifest themselves through low values obtained in Charpy impact and crack tip opening displacement (CTOD) tests. Although it is possible to locate areas of low toughness in linepipe seam welds, it is not clear if these are structurally significant. If it can be shown that low toughness areas in the seam weld HAZ do not affect the fitness for service of the pipe as a structure, these could be accepted for use. Under funding from PRCI, a study has been carried out to investigate this problem quantitatively. Experience in the offshore structural field, where the similar problem of local brittle zones in weld HAZs has received considerable attention, was reviewed. A constraint based fracture mechanics analysis was developed using the T-stress approach. Cracked body finite element analyses were used to obtain the T-stress for a range of surface breaking and buried defects in typical linepipe geometries. The results from these models were used to develop a constraint modified Failure Assessment Diagram for a fracture analysis. Fracture analyses showed that the structural constraint is low and failure will occur by plastic collapse for practical seam weld defect sizes. This shows that even when the seam weld toughness is very low, the dominant failure mode for the structure will be plastic collapse. Hence the low toughness values obtained in fracture mechanics tests are not structurally significant for practical defect sizes likely to occur in linepipe.
Materials and Spare Parts Management for Gas Pipelines
Authors: Andrade Reinaldo
Published: December 2008

The challenge for materials and spare parts management is to keep an economical inventory level and assure reliability to end-users. Another challenge is to have end users committed to the management model and procedures. The usual models call for re-order points and statistics analyses that do not fit the normal demand profile of pipelines. The proposed model works in committees by equipments or installations (as compressor stations, city-gates, etc.). The committee defines the necessary level of reliability for each material or component, estimated demand, normalized specification, etc. The Stock Base model supplies the statistical support for defining the quantity to maintain during the leading time plus a standard interval between semiannual or annual analyses. The model combines the most important concepts practiced by material management: Pareto’s Principle to indicate the economical standpoint to be considered in the analyses, statistical concepts to indicate the level of reliability required (accepted interval between two consecutive non-stock situation), traditional methods of material management (as the replenishment stock level) and the most important: the end users recommendation. The main results of this model are: low inventory levels, non-repetition of items in stock, different treatment for classes A, B and C items, combination of economical and operational importance resulting in reliability and stock investment reduction.
Determination of Conditional Probability of Dynamic Axial Crack Arrest for Conventionally-Rolled, Lower-Toughness Linepipe Materials
Authors: Rudland D. , Wilkowski G. , Kawaguchi S. , Hagiwara N.
Published: December 2008

This paper presents an analysis procedure to predict the conditional probability of dynamic ductile axial crack arrest within one pipe joint length for pipeline materials operating at temperature above the brittle-to-ductile transition temperature. These analyses assume there is an event to initiate a rupture with probability of one, so that the absolute probability of a fracture event occurring is the probability of the rupture event (i.e., from mechanical damage) times the conditional probability of arrest within one pipe joint. The underlying deterministic model centers on the Battelle Two-Curve approach with a correction to predict the arrest length given the actual material toughness relative to the minimum arrest toughness. Past full-scale experimental results were used to develop statistical parameters that were used with the deterministic model in a Monte-Carlo analysis. This model was calibrated for low-toughness (<150J) and low-grade (<X65) linepipe materials. Example cases are presented to demonstrate the variation of the conditional probability of arrest with the pipeline operating conditions.
China’s Modern Day Great Wall: The 40” West to East Gas Pipeline Project
Authors: Gray Loys A. (Buster)
Published: December 2008

PetroChina’s West to East Natural Gas Pipeline Project (WEPP) has been under construction since October of 2001. Upon completion, construction will be completed on the following major facilities: 3,800 km of 1,016 mm mainline; 294 km of 813 mm, 508 mm, and 406 mm lateral lines; Dual fiber optic conduits with the mainline pipeline; 1,100 km of access roads; 23 metering stations; 18 pigging stations; 10 compressor stations; 16 mountain tunnels; 16 aerial crossings; 41 mainline and 18 lateral line HDDs; 1 crossing of the Yangtze River (a 4.4 m concrete lined tunnel); 3 crossings of the Yellow River (pipe jacking, tunnel and aerial methods); gas control center and SCADA system. This paper covers topics including construction management; engineering, procurement, and construction; major construction challenges; and, business in China.
Environmental Effect of Crack Growth Rate of Pipeline Steel in Near-Neutral pH Soil Environments
Authors: Chen Weixing , Sutherby Robert
Published: December 2008

The laboratory work reported here was initiated to determine whether different soils can be shown to give rise to different growth rate for a given pipeline steel. Two soil synthetic environments with different near neutral pH value were designed based on various soil chemistries collected near the pipeline in the field where near-neutral pH SCC was found. The crack growth behavior in both the environments were determined using compact tension specimen. The crack growth rate was in situ monitored by the potential drop system. It was found that soil chemistry has a profound effect on crack growth rate. Although it is insensitive to the soil chemistry and cyclic frequency, the crack growth rate in the high ΔK regime has been significantly enhanced in comparison with that in air. In the low ΔK regime, the growth rate is shown to have minor dependence on ΔK value but strong dependence on the testing environments. The observed crack growth behavior in different ΔK regimes and environments was related to the crack tip sharpness and crack crevice wideness as a result of corrosion and room temperature creep deformation. Soil solutions with low general corrosion rate are associated with a blunt crack tip and wide crack crevice, which would result in lower stress intensity at the crack tip and weaker crack closure effect, respectively. Similarly, a loading wave allowing shorter creep time on a given volume of material at the crack tip at high loading stress tends to produce a sharper crack tip and narrow crack crevice. These two factors have opposite effect on crack growth rate, and the observed crack growth rate reflects the combined effect of these two opposite factors.
Ductile Tearing of Crack-Like Defects During Hydrostatic Testing of Pipes
Authors: Hippert Junior Eduardo , Teixeira Jose´ Cla´udio Guimara˜es , Peixoto Donato Guilherme Victor , Soriano de Lima Roˆmulo
Published: December 2008

Hydrostatic testing is a powerful tool in pipeline integrity procedures. However, there is the risk that few non-critical defects grow during the test, eventually reaching a quasi-critical size which can cause failure during future operation of the pipe (pressure reversal). This work evaluates the effect of pipeline hydrostatic testing on the ductile crack growth (ductile tearing) of prior crack-like defects. Testing of six segments of 3m length API X60 steel pipes were carried out, each segment containing one electro-sparking erosion part-wall defect of dimensions (a × 2c) 3 × 60mm, 7 × 140mm, and 10 × 200mm, positioned both externally and internally on the base metal. Additionally, for external part-wall defects 3 × 60mm and 7 × 140mm, crack extension was monitored by ultrasonic technique, so that pipe resistance curves of applied load vs. crack depth, J vs. Δa curves, were obtained for each crack configuration. These experimental curves showed good agreement to analytical solutions for defect-containing cylinders under internal pressure. Laboratory resistance curves, J vs. Δa, were obtained from fracture mechanics C(T) test pieces in TL orientation. These curves were used to determine the initiation of stable extension of the defect JIC. Finally, results suggest that JIC is a suitable (conservative) parameter for estimating hydrostatic testing pressure.
The Importance of Online Viscosity Measurement for Leak Detection and Other Simulation Applications
Authors: Nagala Daniel W. , Boufaida Moncef
Published: December 2008

Knowledge of viscosity is an important property in fluid dynamics because it is a key factor in determining the amount of fluid that can be transported in a pipeline during a specific period of time. Dynamic viscosity, defined as the viscosity measured under force induced flow, not only describes the nature of the fluid but is also useful in predicting the behavior of the shear stress with respect to the rate of the angular deformation of the fluid. The addition of the viscous deceleration component in the linear momentum equation is important in describing the real fluid flow in the pipeline. The two factors producing viscosity are cohension and the rate of transfer of molecular momentum. The Reynolds number, which is based on the viscosity, is an important quantity which engineers use to determine if a flow is laminar or turbulent. Hence viscosity plays a major role in the generation of turbulence. Knowing the viscosity is also essential to improving system performance (volumetric efficiency and mechanical efficiency). Because viscosity typically varies among the different fluids transported in petroleum pipelines, it is widely considered that online measurement can be beneficial to pipeline operations. This is particularly true for complex applications that depend on a real-time fluid mechanics model for leak detection, batch tracking, and power optimization, among others.
A Probabilistic Model for Internal Corrosion of Gas Pipelines
Authors: Kale Amit , Thacker Ben H. , Sridhar Narasi , Waldhart Chris J.
Published: December 2008

Locating internal corrosion damage in gas pipelines is made difficult by the presence of large uncertainties in flow characteristics, pre-existing conditions, corrosion resistance, elevation data, and test measurements. This paper describes a preliminary methodology to predict the most probable corrosion damage location along the pipelines, and then update this prediction using inspection data. The approach computes the probability of critical corrosion damage as a function of location along the pipeline using physical models, for flow, corrosion rate, and inspection information as well as uncertainties in elevation data, pipeline geometry and flow characteristics. The probabilistic methodology is based on the internal corrosion direct assessment (ICDA) methodology. The probability of corrosion damage is the probability that the corrosion depth exceeds a critical depth times the probability of the presence of electrolytes such as water. Water is assumed present at locations where the pipeline inclination angle is greater than the critical angle. The corrosion rate is defined to be a linear combination of three candidate corrosion rate models with separate weight factors. Monte Carlo simulation and the first-order reliability method (FORM) implemented in a simple spreadsheet model are used to perform the probability integration. Bayesian updating is used to incorporate inspection information (e.g., in-line, excavation, etc.) and update the corrosion rate model weight factors and thereby refine the prediction of most probable damage location. This provides a systematic method for focusing costly inspections on only those locations with a high probability of damage while allowing future predictions to better reflect field observations.
Evaluation of Carbon/Epoxy Composites for Structural Pipeline Repair
Authors: Kessler Michael R. , Walker Roger H. , Kadakia Dixit , Wilson Jeffrey M. , Duell Joshua M. , Goertzen William K.
Published: December 2008

The University of Tulsa, Citadel Technologies, and T.D. Williamson, Inc. were selected by The Oklahoma Center for the Advancement of Science & Technology (OCAST) for a program of research and testing a non-metallic structural pipeline repair composite sleeve. The name of this composite repair system is Diamond Wrap and the system is based on carbon fabric with an epoxy matrix wrapped around a damaged pipe. Baseline material coupon level testing has been completed on the repair system to compile data to fully define the engineering properties of the current primary product to which all changes and improvements can be compared. These properties include ultimate tensile strength and modulus in the longitudinal and transverse directions, lap shear strength, glass transition temperature, and coefficient of thermal expansion. Full scale fatigue and static rupture tests were also performed on pressure vessels to determine the effectiveness of repairs made using the overwrap repair system.
Innovative Approach for a Pipeline Pre-Operation
Authors: Ferioli Jose´ Fernando M.
Published: December 2008

“Oleoduto Cabiu´nas REDUC - OSDUC II”, a new 183km 10in pipeline, started operating for TRANSPETRO, a subsidiary of PETROBRAS, in September 2002, transporting Natural Gas Liquids from Cabiu´nas Terminal, the on-shore facility responsible for treating all natural gas coming from Campos basin crude oil production fields, to a NGL Fractionation Plant (UFL) inside Duque de Caxias PETROBRAS refinery (REDUC), near Rio de Janeiro. Because the NGL delivered from natural gas treatment process was absolutely free of water and considering the high sulfur content in the wet gas coming to shore, the pipeline was designed to be dried with nitrogen, after construction and hydrostatic tests, regardless of pipe materials specifications, in order to prevent corrosion and hydrogen-induced cracking. Commissioning, the next step, could not be performed as a simple and single operation, because the Liquids Recovery Plant (URL), in the first of three development phases, did not have the capacity either to feed main pipeline pump with the minimum flow required to maintain continuous operation or to assure pig run to be performed within the ideal speed range to guarantee good sealing efficiency. After none of the few available alternatives proved to be suitable, there was no doubt that an innovative approach was the only way to overcome the challenges on commissioning the line under such sort of restrictions despite running risks of postponing pipeline startup in case the filling process did not succeed accordingly. Then, TRANSPETRO engineering team came up with an unusual solution where the line fill process was divided into 8 pumping-stoppage cycles along with the use of polyurethane pigs as a mechanical barrier between liquid and gas phases. This work describes all key factors from pipelines conceptual design, to commissioning procedures and implementation, as well as the tools used to forecast flow conditions and all critical events.
Smart Utility Pigs Used to Determine and Monitor Pipeline Out-of-Straightness, With Specific Reference to Inspection of BP Alaska’s 10” Northstar Crude Oil Pipeline
Authors: Snodgrass Bob , Moore David , Nicholson Barry
Published: December 2008

Through necessity many pipelines and flowlines are required to operate under conditions where their position may be displaced over time. Such movements can occur for a wide variety of reasons, but are most commonly associated with either movement of the physical surroundings of the pipeline causing movement of the pipeline itself, and/or thermal changes in the pipeline causing expansion and contraction. Displacements as described result in the pipeline experiencing increased levels of strain at local out-of-straightness events, potentially resulting in pipeline failure. The ability to measure and monitor pipeline displacements, in particular identifying specific regions of out-of-straightness, is valuable to both the existing pipeline operator who wants to operate their assets safely, and also to the pipeline designer who is able to design future pipelines with the knowledge that such monitoring capabilities exist. Smart Utility Pig technology measures the longitudinal shape of a pipeline using an onboard accelerometer and angular velocity sensors. The data logged by these instruments allows out-of-straightness features to be identified and profiles of the vertical and horizontal shape of each to be calculated. This paper presents an overview of the requirements for such Smart Utility Pig technology, and details of out-of-straightness measurement applications. In particular, projects are identified where the technology has been deployed in such a role, including specific reference to BP Alaska’s 10” Northstar crude oil pipeline.
Type A Sleeve Pipeline Repair Heated by Induction
Authors: de Souza Filho Byron Gonc¸alves , de Marco Meniconi Luiz Cla´udio , Ghizoni Giovano , Frainer Vitor Jose´ , Betanzos Jailson Torma
Published: December 2008

This paper describes the experimental laboratory test in applying a snug fitted pipeline repair sleeve in an 8-inch diameter of non-defective pipe. The sleeve was forced to conform to the carrier pipe by induction heating. That procedure has successfully provided the mechanical interference between pipe and sleeve. The interference was evaluated by stress measurements by using strain gages installed after sleeve application over the pipe, but the measurements were performed during the disassembling of the sleeve.
Optimized Sampling Frequencies for Weld Reliability Assessments of Long Pipelines
Authors: Thacker Ben H. , Carrasco Cesar J. , Warke Robert W. , Amend Bill
Published: December 2008

This work responds to a need to obtain statistically adequate quantities of input data for probabilistic assessments of girth welded pipelines. It is desirable to limit the data collection efforts to that warranted by overall reliability and confidence requirements. This is motivated by the challenge of limited and/or high-cost access to in-service pipelines for property measurement and flaw inspection. The goal of this work is to develop a methodology for specifying the minimum, cost-optimized sampling frequency for each of the model input parameters in a multiple girth weld fitness-for-service (FFS) assessment. The sampling frequency specifies the number of samples for each of the model variables to minimize the given cost function. The methodology is based on a user-specified confidence level for the computed reliability of a given pipeline segment (or segments), as well as the estimated per-sample cost of obtaining data for each parameter. The methodology is implemented as an add-on module in the GirthRel computer program. By expressing FFS in the language of risk-based inspection and maintenance, tools such as the one developed here will be invaluable to the development of a pipeline risk management system.
Pipeline Safety Research and Development at the Office of Pipeline Safety
Authors: Wiese Jeff , Merritt James , Smith Robert , Wood Paul
Published: December 2008

A little over three years ago the US Department of Transportation’s Office of Pipeline Safety (OPS), the agency responsible for the regulation of pipeline safety at the federal level, was directed by the Congress to take deliberate steps to strengthen the regulatory framework, oversight of the nation’s pipeline network, and the technical basis on which pipeline integrity rests. The steps OPS has taken include (a) bolstering existing regulations, (b) creating new management-based and performance-based regulations designed to focus resources on areas where the consequences of failures could be the greatest, and (c) undertaking research and development to support improvement of pipeline safety and integrity. OPS has responded to this direction on many fronts, including by aggressively working with other federal agencies, state and local governments, industry partners and academia, to initiate a broad range of cost-shared research, development and demonstration projects to make pipelines safer. This cooperative effort is designed to attain the fundamental goal of improving pipeline safety performance, thereby contributing to building public confidence in the safety of the nation’s pipelines. This paper describes the OPS strategy and the research, development and demonstration program that has recently been undertaken to implement that strategy.
Regulatory Process Changes at the Office of Pipeline Safety
Authors: Wiese Jeff , von Herrmann James , Wood Paul
Published: December 2008

Over the past several years the Office of Pipeline Safety (OPS) in the Research and Special Programs Administration of the US Department of Transportation has begun to develop and implement a different approach to structuring its regulations and to carrying out the inspections it uses to evaluate operator conformance with the provisions of these regulations. Several new Rules have been promulgated incorporating provisions that are a combination of prescriptive, performance-based, and management-based. These rules include the hazardous liquid integrity management rules for large and small operators, the operator qualification rule, and the gas integrity management rule. The new rules have been designed to allow operators flexibility in their approach to addressing the objectives of the regulations. Such flexibility is needed because of the significant differences in the pipeline infrastructure operated by each company, and the corresponding need to acknowledge these differences to assure the objectives of regulation are achieved without imposing a needless and costly burden on the operators. Promulgation of highly prescriptive “one-size-fits-all” regulations is inconsistent with the variations present in the infrastructure operated by the US pipeline industry. One ingredient in the approach OPS has chosen is the imposition of “management-based” requirements. These requirements are so-called because they prescribe implementation of a program that includes the need for several management practices. The new rules allow some flexibility in which management practices are selected and exactly how they are implemented. Inspection against management-based provisions is different from inspection of purely prescriptive requirements. Management-based requirements provide flexibility in how operators evaluate, justify and change their practices to satisfy the intent of the rule within their unique operating environment. While such changes are designed to lead to improved performance, they will not immediately manifest themselves in recognizable changes in performance, so finely tuned measures of performance are needed to help evaluate the effectiveness of the new requirements. OPS has adopted several mechanisms to aid in the consistent inspection of the management-based provisions of the new rules. These mechanisms are discussed in the paper, as is the OPS approach to answering the question of how it will know if the new approach is working.
Pressure Cycle Fatigue: A Statistical Assessment Approach
Authors: Vieth Patrick H. , Maier Clifford J. , Jaske Carl E.
Published: December 2008

Operational pressure cycle fatigue (PCF) is one of the integrity threats managed by pipeline operators. Usually, hazardous liquid pipeline operators are most interested in the effects of pressure cycles since these pipelines inherently experience more significant pressure cycles than natural gas pipelines. The parameters considered in the assessment of operational pressure cycles include pipe geometry (diameter and wall thickness), mechanical properties of the pipe, distribution of hypothetical defect sizes that may exist in the pipeline, and pressure cycles. In performing these assessments, the most conservative value for each parameter is commonly used for predicting a time to failure. As such, the results are inherently overly conservative. A statistical assessment method, PCFStat, has been developed to more appropriately model the input parameters used in the assessment of operational pressure cycle fatigue; especially for cases where the deterministic approach identifies relatively short remaining fatigue lives. A distribution of each of the input parameters is developed, and then a Monte Carlo simulation of these parameters is performed. The results produced by this analysis are then used to evaluate the probability of a failure (leak or rupture) for a defined time interval.
Assessment of Pipeline Station Facilities Integrity
Authors: Jaske Carl E. , Lopez-Garrity Aida
Published: December 2008

This paper describes an approach for assessing the integrity of pipeline station facilities, excluding the transmission pipeline itself. It includes the development and implementation of an integrity management plan, an inspection plan, and a fitness-for-service assessment plan. These plans are adapted from accepted industry standards and implemented in accordance with accepted industry recommended practices. Risk-based assessment is used to prioritize inspections and schedule mitigation actions, including repairs and replacements. Anomalies and defects in equipment are assessed using fitness-for-service procedures. Application of the approach to station and terminal facilities is discussed.
The Pipeline Leak Location Techniques Based on Modal Acoustic Emission
Authors: Jiao Jingpin , Wu Bin , He Cunfu , Fei Renyuan
Published: December 2008

Due to the multiple modes and dispersive nature of acoustic leak signal propagation in pipeline, the traditional AE cross correlation method was ineffective to location the leak in pipeline. Based on the theory of modal acoustic emission (MAE), two different pipeline leak location techniques are brought forward. One is based on two modes with one sensor; the other is based on one mode with two sensors. The general process is narrated as following three steps. Firstly, based on the theory of guided waves propagation in cylinder, the acoustic leak signals in positions nearby the sensor(s) can be predicted using the information of dispersion characteristics of guided waves in pipeline and the acoustic signal received by the sensor(s). Secondly, by transformed the predicted signals in time and space, two (one) individual modes (mode) of the acoustic signal at the position of the sensor(s) are isolated. By correlated the two modes of the same sensor (one mode of the two sensors), the leak position can be located accurately. The leak location experiments have been carried out to prove the validity of the one sensor and two sensors leak location techniques; it is indicated that the location errors of the two leak location techniques are usually less than 5%, and the techniques can be used to location the leak of pipeline filled with liquid or gas.
Long Term Performance of Fusion Bond Epoxy Coated Pipelines
Authors: Worthingham Robert , Cetiner Matt
Published: December 2008

TransCanada Pipelines has been using fusion bond epoxy (FBE) external coatings for large diameter line pipe since the early 1980’s. Overall, this coating type, when applied in accordance to the CSA Z245.20 standard provides excellent protection and long term service life. However, some reports from the field described the periodic occurrence of blistering and disbondment of the coating. In order to understand the magnitude and causes of these phenomena, an investigative program was initiated. Laboratory tests and a program of field examinations were carried out. Some of the variables considered were: age of the coating; service temperature; cathodic protection (CP) levels; and soil type. No evidence of a pipeline integrity threat associated with fusion bond epoxy deterioration was found at any of the locations examined. Observations and correlations of coating to exposure conditions will be presented.