bluuebunny/crossref_metadata_2025 huggingface dataset:
Buried Steel Pipeline Design: External Load Methodologies and Strain Limits
Authors: Chou Z. L. , Wittenberg L. J. , Adeeb S. , Cheng J. J. R.
Published: December 2014

Buried steel pipelines are one of the most efficient means of transporting oil and gas from their resource deposits to their markets. The pipeline industry is experiencing an increased demand for larger diameter pipelines along with the implementation of thinner walls and higher operating pressures.

In these cases, the external pipeline loads have significant effect on the pipeline stresses and deformations, thus influencing wall thickness and associated cost effectiveness. The external loads are made up of the weight of the backfill material combined with live and impact loads due to traffic.

For the designs of buried pipelines, API RP1102, CSA Z662, American Lifelines Alliance (ALA) “Guidelines for the Design of Buried Pipelines”, ASCE “Design and Installation of Buried Pipes” and AWWA Manual M11 are commonly used to calculate external loads on buried pipelines. For the calculation of backfill loads, these methods are based mainly on the same theory, i.e., Marston load theory, while the calculation of live load, due to traffic loads, is based on different approaches. Depending on the design methodology selected, there is a large variation in the calculated external loads due to both backfill and live loads. In this paper, the experimental results of a field monitoring program will be compared with the calculated results from the various methods. An alternative approach for calculating external loads is presented and verified to field studies.

In addition, for the design of onshore pipelines the industry uses design criteria which are based on allowable stress and ovalization deformation limits. Pipe stresses and deformations resulting from the external loads are commonly based on the Spangler stress and the Iowa equations. The parameters in the formulas include pipe and soil properties, pipe-soil stiffness and the geometric relation of a pipe section during deformation. As pipe materials, pipe sizes, operating means and pipe coating techniques change over time, the allowable design criteria shall be re-examined, especially for the ovalization deformation limits. In this paper the allowable strain and the corresponding ovalization deformation limits are re-examined by reviewing experimental results and industrial requirements.
Pipeline Leak Detection Technologies and Emergency Shutdown Protocols
Authors: Geiger Gerhard
Published: December 2014

Pipelines are the least expensive and most efficient way to move liquids and gases, but there is a high potential risk of danger in case of a leak. This paper therefore describes pipeline leak detection technologies and emergency shutdown protocols to ensure reliable and safe pipeline operations. The main focus of this paper is on internal leak detection systems which use existing field instrumentation and usually run continuously. External leak detection systems using dedicated measurement equipment such as probes and sensor cables are briefly considered. Particular emphasis will be placed on model-based techniques such as the Real Time Transient Model (RTTM) and Extended Real Time Transient Model (E-RTTM) methods. In case of a leak, appropriate emergency actions are required to limit the consequences and in particular to protect people and the environment. The last part of the paper therefore is devoted to emergency shut-down protocols.
Pipeline Aerial Crossings
Authors: Johnson Murray M.
Published: December 2014

Modern pipeline construction includes many techniques for safely burying the pipe beneath watercourses or other obstacles with minimal environmental impact. Situations often occur, however, where bringing the pipe above-ground to cross an obstacle on a purpose-built bridge may be necessary or preferred. Such aerial crossings are often used for steep-sided deep canyons, streams with sensitive aquatic habitat, rivers with shifting or unstable beds or deep scour potential, and where sub-surface conditions are unsuitable for horizontal directional drilling.

This paper explores situations where an aerial crossing may be called for and outlines various structure types that may be used, including girder bridges, space trusses, and cable-supported bridges. Factors affecting selection of structure type are discussed, along with design criteria, pipe support methods, expansion provisions, durability, and inspection access. General construction issues are also covered, including access requirements, foundation considerations, fabrication, methods of erecting superstructures, and pipe installation.

Examples are provided of aerial crossings for gas, oil, and water pipelines that have been constructed in the past several decades, as well as crossings now under construction or being designed.
Implementing an Algorithm and Training the Console Operators of the TRANSPETRO Integrated Gas Pipeline Networks for Decision-Making in Scenarios of High Psychological Pressure
Authors: Merçon Eduardo G. , Peres Paulo Bruno V. , da Fonseca Maurício G. , dos Santos Arnaldo M. , Penavilla Anderson
Published: December 2014

The National Control and Operation Center (CNCO) of Petrobras Transporte S.A. — TRANSPETRO — is responsible for the remote and uninterrupted operation (24 hours a day and 7 days a week) of approximately 7,100 km of gas pipelines, including 11 compression stations and around 135 city-gates. Its Control Room, located in the Head Office of the company in Rio de Janeiro, is composed of a structure of five consoles, monitored by a team formed by four operators and one supervisor.

The purpose of this work is to present and discuss the implantation of a systemic tool that enables the decision-making of the CNCO operators in scenarios of high psychological pressure, so as to incorporate the values of the organization relative to the environment, safety, the assets of the company and society in general.

The first step was the development of the tool, a process achieved based on an algorithm that quantifies the degree of severity of a gas leak from a set of scores and weightings attributed to ten items in a standard questionnaire. This involves factors relative to: the source of information; the time of arrival of the local emergency group or third parties; location, intensity and categorization of the leak; impacts on the community, the environment and the gas transport customer, and the internal classification of critical facilities, among others.

The application of the algorithm questionnaire results in the Evaluation Index of Occurrence (EIO), whose maximum value, which reflects the worst scenario, is 1000. For values of EIO below 600, the emergency is considered to be under control. During the event, the algorithm should be calculated every 15 minutes, so that the rate of variation in the EIO is also monitored and utilized in a decision-making flowchart. Ultimately, based on a questionnaire and flowchart structure, the algorithm aims at rendering information in numbers and actions.

The second stage of the work is the training of the operators, where the program is composed of a theoretical part and a practical part. The theoretical part is based on services contracted from a consultancy with recognized expertise in the Brazilian market. The practical part is carried out in a simulation environment involving our own simulator software and emergency scenarios developed by CNCO together with the consultancy. The software reproduces in different degrees of difficulty, all the conditions of a real leak and the psychological pressure involved. This process will be evaluated by a qualified instructor who will assess the progress of the operator.

Finally, the work also shows how the tool is being incorporated into the operational processes of CNCO, aiming at taking action that is standardized, safe, fast and effective in the mitigation of leakage events.
Effects of UOE Manufacturing Process on Pressurized Bending Response of Offshore Pipes
Authors: Chatzopoulou Giannoula , Karamanos Spyros A. , Varelis George E.
Published: December 2014

Thick-walled steel pipes manufactured through the UOE process are used in deep-water pipeline applications for the safe and cost-effective transmission of hydrocarbon energy resources. Such pipes are subjected to bending loads in the presence of high external pressure during their installation stage. The combination of bending and external pressure often triggers the development of structural instability due to excessive ovalization of the pipe with catastrophic effects. In the present study, the effect of UOE line pipe manufacturing process on the bending response of externally-pressurized thick-walled pipes is examined, using finite element simulation tools.
Application of Multi-Nodal Network Simulation Models in Debottlenecking Complex Pipeline Network
Authors: Cernelev Dumitru , Chegus Allan , Lin Frank
Published: December 2014

The problem of identifying and removing bottlenecks in a multi-terminal oil & gas pipeline network while achieving quality and delivery targets is a very real and complex problem. The most effective way to meet the above business objective is to develop a terminal network simulation model.

This paper is a case study describing the approach in designing a complex multi-nodal pipeline network simulation model with objective to resolve a critical inter-company storage problem for a major refiner.

Various complex system modeling techniques and approaches are elaborated with a focus on practical application. A case study is also presented to demonstrate the practical application of the modeling techniques for terminal network simulation model development.
Short Term Hydrotechnical Risk Control Measures Used During the Implementation of Watercourse Pipe Replacement Projects
Authors: Dewar Doug , Costerton Bob , McClarty Edward , Bracic Jan
Published: December 2014

Pipeline watercourse crossings are designed according to the best available industry/technical standards at the time of construction. Older pipeline systems were typically installed without the benefit of modern hydrotechnical engineering practices with little or no allowance for ongoing fluvial processes. The level of protection at specific crossings can deteriorate such that a relatively small flood (i.e. 1:10 year) can pose a significant integrity threat.

The hazards associated with maintaining an existing crossing may not be acceptable for the continued safe operation of a pipeline; therefore, a pipe replacement may be required. The designing, planning, permitting, funding, contracting and construction of any pipe replacement option can require considerable time to implement. In most watercourses in Canada and the United States this means that the pipeline at risk, but not in an emergency situation, will likely go through at least one spring freshet and/or other seasonal peak flow event(s) prior to implementation of the pipe replacement project.

Four examples of short term risk control measures are discussed for river crossings in and around central and northern British Columbia, Canada.
Onshore Natural Gas and Hazardous Liquid Pipeline Natechs in the USA: Analysis of PHMSA Incident Reports
Authors: Girgin Serkan , Krausmann Elisabeth
Published: December 2014

Natural hazards can be initiating events for accidents in oil and gas pipelines. Severe past incidents bear testimony to the risk associated with pipeline accidents triggered by natural hazards (natechs). Post-incident analysis is a valuable tool for better understanding the causes, dynamics and impacts of such accidents. To identify the main triggers of onshore transmission pipeline natechs in the USA, natural gas and hazardous liquid incident reports collected by the Pipeline and Hazardous Materials Safety Administration were analyzed. Potential natech incidents were identified by automated data-mining followed by expert review. The analysis covered ∼21,000 incidents, about 6% of which were identified as natechs. Geological hazards triggered 50% of the identified natechs, followed by meteorological (25%), climatic (11%), and hydrological (11%) hazards. Landslides are the main geological hazard with 43% of the incidents within the category. Among meteorological hazards, lightning is the major hazard with 36%. 84% of the hydrological hazard related natechs were found to be due to floods. Cold-related hazards make up 93% of the natechs caused by adverse climatic conditions. Some preliminary qualitative results on consequences are provided as well.
The Development and Application of Virtual Flow Metering System in Offshore Gas Field
Authors: Wang Zhi , Gong Jing , Wu Haihao , Li Qingpin
Published: December 2014

Well flow rate surveillance is essential for reservoir characterization and selecting potential activities and optimization production. Ideally, surveillance would be achieved using multiphase meters on each well, but generally it is not economically feasible especially for subsea production system. Therefore, the technology of virtual flow metering comes up.

In this paper, the development and application of virtual flow metering system, used for determining production rates including gas oil and water flowrates in well, is discussed. Without any metering devices, the system, developed by China University of Petroleum, can automatically estimate single well and whole production rates every five minutes, only taking advantages of the instrumentations typically installed on wells. In hardware, the system is mainly made up of two servers, one of which in charge of communication, the other calculation. In software, the core algorithms are based on validated models of well hydraulics and flow through choke in oil industry. Also, the components and heat transfer influence is also taken into considered by their corresponding models. Based on these models, three independent algorithms are established for well flow rates prediction. Each algorithm is replicable for others in order to prevent measurement distortion and end caused by individual instruments faults. The value of estimated flow rate uncertainties in addition to real-time continuous well flowrate estimates is described. The flowrate basis on a daily or weekly reconciled by real-time calibration program basing on calculated uncertainties.

The system practically applied in one subsea production system producing gas-condensate. In field commissioning, the system showed a great accuracy. The total mass flow rate and volumetric flowrates for each phase at standard conditions calculated with VMS showed a great agreement with the field data. The maximum error is below 10% and the averaged error is nearly 5%.
Risk Assessment Procedures and Prioritization of Mitigation Actions in Pipeline Crossings
Authors: da Costa Victor Carlos Teixeira , de Paula Eduardo Lopes , de Souza Lima Deise , Gonçalves Bruno Martins
Published: December 2014

Pipeline operators usually are very concerned to reduce the possibility of damage to their facilities by third-party action. The third-party action is an important failure mode in buried pipelines. Pipeline crossings are a point of special consideration in assessing the risks due to damage possibility by others. In general, means of protecting the line from mechanical damage are used in these situations. These means include concrete coatings of different thickness, pipe casing, concrete slabs, warning tapes, warning mesh and signs.

When a new pipeline is under construction mechanical protection is in general considered in the design phase. However due to urbanization and construction of new roads many new pipelines crossings can exist without any additional mechanical protection. Due to the large amount of such points, there is no feasible plan to act on every single point at the same time. This happens due to problems controlled by financial, time and technical resources. Such a cumbersome task demands a procedure to assess the risks due to third-party action, to rank the points and to receive proper treatment.
Limit States Design for Onshore Pipelines: Designing for Hydrostatic Test Pressure and Restrained Thermal Expansion
Authors: Adianto Riski H. , Nessim Maher A.
Published: December 2014

Reliability-based design rules have been developed for the key serviceability limit states applicable to onshore pipeline including local buckling due to thermal expansion and excessive plastic deformation under hydrostatic test pressure. The design rules are characterized by three elements: the formulas used to calculate the characteristic demand and capacity; the criteria used to define the characteristic values of the key input parameters to these formulas (such as diameter and material strength); and the safety factors defining the required excess capacity over the demand.

The overall methodology used in developing the design rules and the practical implications of applying them are described in a companion paper. This paper describes the process used to calibrate safety factors and characteristic input parameter values that meet the desired reliability levels. The results show that local buckling under restrained thermal expansion is only potentially relevant for a small sub-set of cases and based on this, an explicit design rule was not developed. For excessive deformation under hydrostatic test pressure, two alternate design rules are provided; one stress based and the other strain based. The final design rules are described and an assessment of their accuracy and consistency in meeting the reliability targets is included. Guidance is also provided on the conditions in which each check is used.
Mode Mixity in the Fracture Toughness Characterization of HAZ Material Using SEN(T) Testing
Authors: Kalyanam S. , Hioe Y. , Shim D.-J. , Wilkowski G. M.
Published: December 2014

Single-Edge-Notch-Tension, SEN(T), specimens have been found to provide good similitude for surface cracks in pipes, where a surface-cracked structure has lower constraint condition than bend-bars and C(T). The lower constraint condition gives higher upper-shelf toughness values, and also a lower brittle-to-ductile transition temperature. Also, the SENT specimen eliminates concern of material anisotropy since the crack growth direction in the SENT is the same as in a surface-cracked pipe. While the existing recommended and industrial practices for SEN(T) have been developed based on assumption of monomaterial across the crack, their applicability for the evaluation of fracture toughness of heat-affected-zone (HAZ) is evaluated in this paper. When conducting tests on SEN(T) specimens with prescribed notch/crack in the heat-affected-zone (HAZ), the asymmetric deformation around the crack causes the occurrence of a combination of Mode-I (crack opening) and Mode-II (crack in-plane shearing) behavior. The extent of this mode mixity is dependent on the relative difference between the material properties of the adjacent girth weld and pipe base metals, as well as the amount of crack growth in the test. This mode mixity affects the measurement of the crack-tip-opening-displacement (CTOD) and evaluation of fracture mechanics parameter, J. The CTOD-R curve depicts the change in toughness with crack growth, in a manner similar to the J-R curve methodology. Observations also show a mismatch in the length of the crack growth that is measured on the fracture surface, attributable to the material deformation differences across the two adjacent materials (weld and base metals). This paper discusses the experimental observations of Mode-I and Mode-II behavior seen in tests of SEN(T) specimens with notch/crack in the HAZ and as the crack propagates through the weld/HAZ thickness. The paper addresses the issues related to and the changes needed to account for such behavior in the development of recommended practices or standards for SEN(T) testing of weld/HAZ. The effects of mode mixity in HAZ testing is critical to the development of crack growth resistance, CTOD-R and J-R curves employed in Engineering Critical Assessment (ECA) of pipelines.
Effects of High-Low Misalignment on Girth Weld Integrity
Authors: Wang Yong-Yi , Kotian Kunal , Rapp Steve
Published: December 2014

High levels of high-low misalignment in pipeline girth welds have been identified as one of the possible contributing factors to some of the recent pre-service hydrostatic test failures or subsequent service failures. However, pipeline service experience indicates that nominally defect-free girth welds with high levels of misalignment and proper weld profiles can provide satisfactory long-term service. In this paper, recent analytical and experimental work aimed at understanding the impact of high-low misalignment in girth welds is described. In nominally defect-free welds, the performance of the welds is found to be predominantly determined by the misalignment ratio, weld strength mismatch ratio, and the weld profile. Iso-load-capacity relations are developed through finite element analysis (FEA) to capture the interdependence of those key parameters. The analysis procedure is validated by cross-weld tensile testing of girth welds with various levels of misalignment and weld strength mismatch. The effects of the circumferential extent of misalignment, alternatively termed local misalignment, are also analyzed. The effects of misalignment in girth weld with planar flaws are examined in the context of the tensile strain capacity.

The analytical and experimental evidence indicate that the absolute level of misalignment is not a sole indicator of girth weld performance. Weld transition profile, pipe wall thickness, and weld strength mismatch all play an important role. With proper weld profiles, minimal or small reduction of load capacity is observed even at very high levels of misalignment. Work is continuing to further examine the effects of high-low misalignment with a goal of making practical recommendations to be included in codes and standards.
SCC In-Field Inspection Technology Evaluation and its Application to EMAT Based Pipeline Integrity Management Programs
Authors: Tandon Samarth , Gao Ming , Krishnamurthy Ravi , Kania Richard , Piazza Mark
Published: December 2014

Most recently, as a complement to the ongoing efforts to monitor and document improvements in EMAT ILI technology, PRCI conducted an extensive study of NDE inspection technologies for characterizing SCC in pipelines using various in-ditch technologies and methods. The test pipes used for the study were cut outs from an operating pipeline where SCC features were identified and sized using EMAT ILI technologies. These are now sized with the NDE study and correlated with EMAT data to support an improvement of EMAT technology in characterizing SCC features. More importantly, the test pipes were burst tested to failure, with post failure analysis completed to fully characterize the crack features, including detailed length and depth measurements. This complete data set provides a comprehensive view of the current capabilities of NDE inspection technologies and EMAT ILI technologies to detect and characterize SCC and crack-like features.

In this paper, the approach used for the evaluation of in-ditch NDE and EMAT ILI technologies is presented first. The in-ditch NDE technologies used for evaluation which were commonly used for SCC characterization are then described. SCC characterization results from in-ditch NDE and EMAT ILI are summarized and compared to those directly measured from fracture surfaces exposed by burst tests. The findings and its application to pipeline integrity management programs are discussed.
Pipeline Stress Relief and Evaluation of Strain Measurement Technology at a Moving Slope
Authors: Dinovitzer Aaron , Fredj Abdelfettah , Sen Millan
Published: December 2014

A major slope in southern Manitoba has been experiencing deep seated movements of approximately 60mm per year. This 24m high × 85m long slope contains a pipeline right of way with five large diameter crude oil lines that were constructed from 1950–1998. It is estimated that the slope has moved up to 3 meters since the pipeline installations. Management of the effects of this slope movement on the pipelines has involved cross-functional strategies that include geotechnical, integrity, and stress evaluations.

A finite element analysis (FEA), which considers the interaction between the soil movement and pipeline, was generated to evaluate the pipeline stresses caused by the slope movements to date. The results indicated that the strain capacity on one of the pipelines may be near its limit. Correspondingly and in order to be conservative, a stress relief was conducted on three of the pipelines within the right-of-way. This mitigation involved excavating the pipelines 360 degrees which allowed for their decoupling from the surrounding soil, and the associated pipeline spring back was surveyed. Prior to backfilling, a low friction geotextile was installed around the excavated pipelines to help mitigate future movements. Drainage improvements and a toe berm were also installed to improve the slope stability.

Several strain measurement technologies that have been the subject of previous Pipeline Research Council projects were also installed at the site. Stress probe measurements were taken before and after the stress relief; a fiber optic cable was installed; inline inspection bending strain measurements were analyzed; and the FEA analysis was used to model the strains before and after the stress relief. All of these technologies are compared to the measurements from strain gauges that were read both before and after the stress reliefs were conducted.
Why Projects Fail (and What We Can Do About It)
Authors: Schoenhardt Matthew B. , Pardais Vachel C. , Marino Mitch R.
Published: December 2014

Over two-thirds of all mega projects result in failure, meaning they significantly exceed budget, miss schedule targets, or fail to achieve production close to design capacity. The reasons for project failure have been well documented over the past fifty years. Despite this large body of empirical evidence, many executive and project leadership teams continue to repeat the mistakes made on past projects. This can be partially attributed to project teams believing that their projects are somehow different from past projects and that others’ project mistakes are not relevant to their project. This paper is a literature review that considers the seven common root causes of project failure and how these root causes relate to the pipeline industry. No new primary data will be presented. The seven common root causes for project failure and their approximate impact on budget variance are:

1. Failure to complete front end loading = 60–85%

2. escalation = Up to 12%

3. Regulatory regimes = Up to 12%

4. Plant complexity = Up to 20%

5. New technology = Up to 20%

6. Solid feedstock = Up to 10%

7. Complex ownership = Up to 24%

This paper will also review and discuss seven common project traits closely associated with project failure, although not direct root causes. These traits are:

1. Concurrent detailed design and construction = up to four times greater risk profile

2. Non-integrated project team = up to three times greater risk

3. Contractual risk misallocation = up to two and a half times greater risk

4. Fast-tracking projects = up to two times greater risk

5. Lack of internal capacity = up to two times greater risk

6. Oil and Gas industry = up to two times greater risk

7. Brownfield vs. greenfield site = no direct impact

With these root causes and traits identified, several methods of risk and contingency analysis will be examined. An evaluation of each method’s ability to increase the success rate of capital projects will be discussed; ultimately, resulting in a recommendation on the optimal risk and contingency framework for improving project success rates. The paper will conclude with a summary of how Stantec’s risk and contingency framework is being implemented on pipeline projects.
Petrobras Transporte S.A.: Transpetro’s Ultrasonic Flow Meter Recalibration Program
Authors: Carvalho Thomaz , Ferreira Ana Luisa , Lourenço Tulio C.
Published: December 2014

In recent years, the use of ultrasonic flow meters has gained worldwide acceptance for natural gas custody transfer applications. TRANSPETRO has also increased significantly the use of this technology because of the important role it plays in reducing lost and unaccounted for (LUAF) gas. A plan of this equipment is essential to guarantee the proper operation and the specified accuracy of the meter runs as well as mandatory in order to comply with a national regulatory agency (ANP) ordinance, which requires ultrasonic meters to be recalibrated every 30 months. This interval can be extended if the agency approves a study submitted by the operator, presenting a reasonable historical metrological performance the meters. In 2009, the Measurement Technical Committee of the Pipeline Research Council International (PRCI) published a report recommending ultrasonic meters to be recalibrated based on time-in-service, but on periodic assessment of the diagnostic parameters provided by the equipment. The report states that if these diagnostic logs indicate performance change, the meter should be cleaned and the performance re-checked; the recalibration should be considered only if the performance change remains after the cleaning. Carrying out this procedure guarantees, according to the report, the calibration is within the uncertainty of the calibration facility for a period of at least six years. Although the several PRCI reports recommend some diagnostic parameters to be followed, their names, categories and limits vary from manufacturer to manufacturer. A narrow relationship with each manufacturer must be established in order to define the finest practices. The periodic basis of the diagnostic logs collection is also an important concern. The state-of-art on following the diagnostic parameters is to have them integrated to the SCADA system, random problems can be neglected if manual collection is performed from time to time. The objective of this paper is to present TRANSPETRO’s ultrasonic flow meters recalibration program based on PRCI reports and manufacturers’ recommendations, as well as show the company’s strategy for the diagnostic parameters collection.
Experimental Investigation on Combined “Dent and Gouge” Defects on Vintage Steel Transmission Pipelines
Authors: Zarea Mures , Hertz-Clemens Stephane , Batisse Remi , Cardin Philippe
Published: December 2014

Mechanical Damage on pipelines is the most frequent in service failure cause, at least in Europe. The category of Mechanical Damage actually covers on one hand rock dents, on the other hand, combined “Dent and Gouge” defects resulting from an impact by a ground moving machinery. The latter are complex defects in terms of geometry and mechanical behavior. Improved understanding of toughness reduction in these defects and their vicinity, especially in the case of vintage pipelines, and its impact on burst pressure and remaining fatigue lifetime is crucial in order to ensure a high safety level at the best economic conditions for transmission pipelines. PRCI and DOT/PHMSA supported a large experimental program to investigate the burst and fatigue strength of such defects in modern pipes as well as in vintage pipes by producing very detailed reference experimental data in order to support improvement of current burst and fatigue strength models for these defects.

This paper focuses on experimental results data for two vintage pipes removed from service, one 26″ in diameter, X52 grade (from US) with high carbon content and sulfur content involving very low toughness and another 24″ in diameter, X63 grade (from Europe) characterized by alternated pearlite and ferrite bands. In each pipe, two different types of combined “Dent and Gouge” defects were created, “shallow dent with shallow gouge” and “severe dent with moderate gouge”. Each defect was reproduced three times:

• One for destructive metallurgical investigation;

• A second one for highly instrumented burst test;

• A third one for highly instrumented fatigue test.

The defect profile was monitored during pressure increase until burst, and a camera recorded pictures at each fatigue cycle to detect crack initiation at the gouge bottom and its further propagation. The different features of the experimental work and results described in this paper are:

• Material characterization;

• Metallurgical and residual stress investigation on combined dent and gouge defects;

• Burst tests conditions and results;

• Fatigue tests conditions and results.

• Comparison with results from modern pipes containing the same types of defects.

All this experimental data is made available for an in-depth understanding of the “Dent and Gouge” type defects leading to improved models, as well as reference data for validating these improved models for burst and fatigue strength of these defects.
Benchmarking Consequence Models With Actual Pipeline Events
Authors: Pettitt Glenn , Ramsden Martyn , Shackleton Janine
Published: December 2014

This paper describes how past pipeline incidents can be used to test whether the consequences of major hazard events as predicted by computer model are realistic.

Most materials transported by cross-country pipeline are flammable in nature, e.g. crude oil, petroleum products and natural gas. The hazardous consequences of a loss of containment may be modelled by a variety of computer models. One of the key inputs is how the failure may be modelled, in terms of the initial source terms and how the released material behaves subsequently. Modelling appropriate behaviour of the release is incumbent on the modeller / engineer, as well as accurately interpreting the output from the computer model.

There have been a number of high profile pipeline incidents in recent years that have had a devastating effect on the local community. Although one recognises the distressing effects of such incidents, these also provide an opportunity to test the consequences predicted by computer models. One of the key questions is whether it is likely that the adverse effects of an incident are overpredicted by the modelling inputs / technique and therefore whether the outputs from the model present a conservative thermal radiation dose.

This paper presents such a benchmarking exercise, which has been carried out to assess the degree of realism provided by computer modelling and the way in which the modelling is carried out. This exercise was conducted following a number of pipeline risk assessments where it was predicted that in some cases, hundreds of fatalities may occur following rupture of a pipeline transporting natural gas. It was felt that there may be a level of over-conservatism in the modelling, particularly as many incidents that have occurred have not resulted in the predicted level of fatal injuries.
Large Scale Test Apparatus to Test External Leak Detection Technologies
Authors: Apps Chris , Ozkan Istemi , Rizwan Tania , Derakhshesh Marzie , Medynski Scott
Published: December 2014

When it comes to evaluating traditional computational leak detection technologies pipeline operators have a suite of simulated testing methods available. In the last several years however External Leak Detection Technologies have become more mature and potentially could provide operators with another layer of leak detection with more sensitivity than seen in traditional methods. The challenge with these technologies is in the evaluation of their sensitivity, reliability, and robustness. ENBRIDGE INC (Enbridge) and C-FER Technologies 1999 Inc. (C-FER) begun a comprehensive study to assess the state-of-the-art external, continuously distributed sensors for leak detection in early 2012.

Initially, a technology review was undertaken to identify commercial, off-the-shelf technologies with the potential to detect small leaks of oil from buried pipelines. From this literature review, four technologies were identified; Distributed Temperature Sensing (DTS), Distributed Acoustic Sensing (DAS), Vapor Sensing Tubes (VST), and Hydrocarbon Sensing Cables (HSC). All four methods require proprietary materials and technology, which have had limited independent testing efforts to date. To evaluate these four leak detection methods and their vendors in an objective way, Enbridge and C-FER initiated the design and construction of a large-scale External Leak Detection Experimental Research apparatus (ELDER) that can accommodate a full-size segment of pipeline within a trench, at the same scale used in pipeline construction in North America. An instrumented pipe segment is buried in the trench with sensing cables laid alongside. The apparatus generates leaks with controlled variables including rate, pressure and temperature, and at various locations to accurately represent pipeline leaks. This paper summarizes the literature review on the four selected leak detection technologies that were identified as candidates for large-scale evaluation. The discussion will also include features of the ELDER apparatus, and re-engineered pipeline construction techniques that were required to accurately represent a full-scale pipeline trench within a laboratory environment.
The Pipe Inspection Lifecycle
Authors: Nemeth David , Walda Troy I.
Published: December 2014

Energy Transfer has implemented a new, comprehensive field-inspection system for the pipe inspection lifecycle that encompasses aerial observations, pipe exposures, foreign line crossings, in-line inspections, anomaly remediation, pipe inspection, and integrity sheet generation. In order to ensure the integrity of the pipe inspection program, the field inspection solution required full audit-trail capabilities, front-side data validation, and full integration with the corporate-wide GIS and Engineering Data Management System. Additionally, to ensure the success of the new inspection program, the inspection solution required a highly intuitive and field user-friendly interface, the ability to work equally well in both connected and disconnected environments, interactive mapping functionality, very high reliability, and a process-driven architecture.

Energy Transfer owns and operates approximately 43,000 miles of natural gas, natural gas liquids, refined products, and crude oil pipelines. Due to the size and diversity of Energy Transfer’s assets, the corporate GIS system must be distributed across seven independent instances consisting of server pools and large-scale relational database management systems (RDBMS). Although each system must be functionally independent, the field inspection system and the inspection process must interact with each server and RDBMS instance with equal functionality and be able to report on all pipe inspection activities across the enterprise.

The inspection system is used by over 1,200 Energy Transfer employees and contractors, and approximately 15,000 inspections are performed annually. The system supports a variety of devices, such as: laptops, tablet computers, iOS devices (i.e., iPads, iPhones), and Android devices. Whether on foot, in vehicles or aircraft, users can enter information from the platform that best meets the needs of their individual environment. Information collected on any device is available for continuance of the pipe inspection lifecycle on any other device and is available in real time at the corporate offices via a Web portal. The Web portal provides visualization tools for both business and engineering analysis such as progress tracking and remediation planning. These functions are supported through the portal’s integrated mapping, dash boarding, and a reporting functionality that includes advanced search capabilities for both comparative and predictive analysis. In addition to utilization for the pipe inspection lifecycle, the inspection system is being used for a variety of other inspection and regulatory compliance-related activities, including: cathodic protection, incident reporting, corrosion assessment, DOT structure location, MAOP-MOP establishment, shallow cover, unmetered gas loss, and many more right-of-way related activities.
Understanding of the Risks of High Pressures Following Rapid Pressurization in Pipelines Containing Entrapped Air Pockets: A Novel Energy Auditing Approach
Authors: Malekpour Ahmad , Karney Bryan
Published: December 2014

Rapid pressurization of liquid pipelines containing entrapped air may result in extreme overpressures. Both experimental and numerical studies have shown that the magnitude of the induced pressure has important sensitivities to many physical parameters even though the complex nature of the system’s transient responses has tended to obscure the physical mechanisms themselves. To provide insight and guidance to key design issues, this paper proposes an energy auditing approach to elucidate the physics of the transient events leading to the extreme pressure rise during pipe rapid pressurization events. The proposed approach is then utilized to provide physical understanding of the features of the flow and the system parameters affecting the maximum pressure rise during rapid pressurization of pipe system. Both rigid column and elastic numerical models are then employed to verify the results obtained from the proposed approach.
Development of Pipeline Leak Detection Technologies
Authors: Zhang Jun , Hoffman Andy , Kane Adrian , Lewis John
Published: December 2014

New development continues in pipeline leak detection technologies in order to meet the increasing demand of the oil, gas, chemical and water industry. After a review of the available technologies, this paper discusses the advances made in two key technologies: statistical volume balance and negative pressure wave.

Some application examples in brine, multi-product and crude oil pipelines are presented to demonstrate the improvement in leak detection sensitivity and location accuracy.
Alternative Geohazard Risk Assessment and Monitoring for Pipelines With Limited Access: Amazon Jungle Example
Authors: Moya John Malpartida , De la Sota Giancarlo Massucco
Published: December 2014

The Pipeline Integrity Management System (PIMS) of Transportadora de Gas del Peru (TgP) has identified the Weather and Outside Forces such as main threat which increases the risk of the integrity of its pipelines in jungle and mountains areas. In pipelines with particular characteristics such as pipeline which crosses the Andes and the Amazonian jungle, this threat can cause even a greater number of failures than other threats such as Corrosion or Third Party Damage (TPD).

Given this situation, the TgP’s PIMS has made a significant development in the use and management of the information provided by different techniques of inspections and monitoring of the pipeline and ROW. Due to the particular conditions of our pipeline system, where the weather and security issues are important restrictions in some locations, makes it impossible to access the right of way in order to get accurate and precise information. Some monitoring depends on people going to the field to collect data (geotechnical surveys, rain monitoring, strain gage measures, inclinometers, etc.). This information is essential to perform the risk analysis in the scope of the PIMS.

This paper shows different alternative techniques of monitoring which allow us to estimate the exposure of the pipelines to Geohazards. Among these techniques we have: topographic surveys with laser-detection LIDAR, monitoring of stress and displacement of the soil by fiber optics, UAV’s (Unmanned Aerial Vehicle) surveys, acoustic leak detection, Inertial Navigation Tools (in line inspection), etc. It is also important to mention the alternative assessment methodologies in order to determine the pipeline exposure, resistance and mitigation to this threat using geological information and exhaustive desk analysis. It is important to get the more accurate information of the actual state of the pipeline system in order to eliminate most of the “default” values during the risk assessment. By integrating these inspections, monitoring and particular assessments as part of PIMS, we have been able get accurate risk assessments in order to mitigate and/or minimize the occurrence of failures. In this way we are able to optimize efforts to preserve the integrity of our system and in addition minimize personal, environmental and business impact.
Effects of Temperature and Glass Transition on the Performance of Polymer Coatings on Steels
Authors: Ha Hung M. , Alfantazi Akram
Published: December 2014

The effects of temperature and glass transition on the corrosion protection behavior of an epoxy/urethane polymer coating on steels was investigated. The polymer experience glass transition at 67 ± 1 °C when heating at 4 °C/min. The ohmic resistance of the coating decreased by 4 orders of magnitude and the coating capacitance increased by about 2 times when the temperature increased from 20 to 80 °C. The ohmic resistance and capacitance of the coatings changed correspondingly to heating and cooling cycles, but the process is not totally reversible. The effect of temperature on the ohmic resistance of the coatings is attributed to the change in the size, the tortousity, and the number of the continuous pores in the coating. The effect of glass transition on the corrosion protection behavior of the coatings during a short period of exposure to a heat source was insignicant.
Quantitative System Specific Likelihood Algorithms for System Wide Risk Assessment
Authors: Kariyawasam Shahani , Wang Hong , Ong Boon , Al-Amin Mohammad , Zhang Ning
Published: December 2014

The System Wide Risk Assessment (SWRA) is an essential first step in the pipeline integrity management program. It is required by both Canadian and US regulators and is expected to estimate risk due to all threats, interaction of threats, and consequences. The main objective of the SWRA is to identify high risk segments so that segments with excessive risk can be mitigated.

The SWRA models developed in this study employs quantified likelihood models and consequence models. A companion paper explains the consequence models. This paper presents the framework and rationale used to produce quantifiable measures of likelihood for each threat. The quantification enables sensible comparisons between threat likelihood values and also enables realistic combining of likelihood values to produce total likelihood of failure due to all threats. It also facilitates identification of key parameters that contribute to each threat.

It is important to have a consistent risk framework that systematically applies to all the threats and accommodates all the different aspects and mitigative actions in each threat management process. For effective continuous improvement it is essential that the models are transparent and updatable. A consistent framework that is systematic, rigorous, transparent and updatable is utilized with explicit consideration to threat interactions.

The main advantages of the likelihood models developed in this study are:

• It is based on all evidence that is available for each threat (failure histories, observations from assessments, i.e., digs, HTs, and ILIs, and mechanistic understanding)

• It considers all nine threat categories and relevant subcategories where causal factors are different (such as SCC and Circumferential SCC within the crack threat category)

• It clearly considers all three types of threat interactions (Interacting coincident defects, Interacting-activating threats, and Interacting common-mode conditions) among all threat categories.

• It is based on subsystem specific historical failure rates for each threat, where subsystem is defined as a subset of pipelines that have different performance characteristics with respect to at least one threat. This basis enables the failure frequencies predicted to be more in line with reality and consequently improves accuracy of predictions and appropriate quantification.

• The subsystem specific historical failure rates are then calibrated to correlate to different mechanistic characteristics so that within-pipeline-subsystem variation due to changes in parameters is represented.

• Finally assessments or observations are used to appropriately update threat likelihood with latest knowledge from measured local observations.

All of the improvements mentioned above have helped the SWRA 2013 to produce more representative results. The comprehensive set of validation exercises verify that the results are realistic.