bluuebunny/crossref_metadata_2025 huggingface dataset:
An Investigation Into the Benefits of Employing Multiple Assessments Methods for High Risk Pipelines
Authors: McMahan Tara , Graf Eric , Bubenik Thomas
Published: November 2018

Selecting the appropriate assessment method for a pipeline system requires an understanding of the pipeline segment, the potential threats to the pipeline segment, and the various assessment methods and technologies available along with their performance capabilities. Each assessment method has its own set of advantages and disadvantages depending on the pipeline and threat being assessed.

In most cases, the assessment of a pipeline segment using one method is sufficient for the management of that threat or threats. However, for high risk pipelines (driven by likelihood, consequence, or both), this paper explores the potential benefits of leveraging one or more assessment methods by examining a number of scenarios with a specific focus on the management of cracks within a pipeline segment. It looks at the benefits of multiple assessment methods employed at the same intervals but in varying order.
Development and Experiences of a Circumferential Stress Corrosion Crack Management Program
Authors: Bates Neil , Brimacombe Mark , Polasik Steven
Published: November 2018

A pipeline operator set out to assess the risk of circumferential stress corrosion cracking and to develop a proactive management program, which included an in-line inspection and repair program. The first step was to screen the total pipeline inventory based on pipe properties and environmental factors to develop a susceptibility assessment. When a pipeline was found to be susceptible, an inspection plan was developed which often included ultrasonic circumferential crack detection in-line inspection and geotechnical analysis of slopes. Next, a methodology was developed to prioritize the anomalies for investigation based on the likelihood of failure using the provided in-line inspection sizing data, crack severity analysis, and correlation to potential causes of axial or bending stress, combined with a consequence assessment. Excavation programs were then developed to target the anomalies that posed the greatest threat to the pipeline system or environment.

This paper summarizes the experiences to date from the operator’s circumferential stress corrosion cracking program and describes how the pipeline properties, geotechnical program, and/or in-line inspection programs were combined to determine the susceptibility of each pipeline and develop excavation programs. In-line inspection reported crack types and sizes compared to field inspection data will be summarized, as well as how the population and severity of circumferential stress corrosion cracking found compares to the susceptible slopes found in the geotechnical program completed. Finally, how the circumferential SCC time-average growth rate distributions were calculated and were used to set future geohazard inspections, in-line inspections, or repair dates will be discussed.
Mechanical Behaviour of Intercritically Reheated Coarse-Grained Heat Affected Zone in High Strength Line Pipe Steels
Authors: Mandal Madhumanti , Poole Warren J. , Garcin Thomas , Militzer Matthias , Collins Laurie
Published: November 2018

Multipass welding of high strength steels used for fabrication and joining of transmission pipelines presents a number of metallurgical challenges. A key concern is both the strength and toughness of the heat affected zone (HAZ) adjacent to both seam and girth welds. In this work, a systematic study has been conducted on regions of the heat affected zone in the base metal where the first welding pass produces a thermal excursion which results in a coarse-grained heat affected zone (CGHAZ). The subsequent weld pass involves intercritical annealing of this region, i.e. a microstructure associated with intercritically reheated coarse grain heat affected zone (ICCGHAZ). The small ICCGHAZ region is often identified as being particularly susceptible to crack initiation. This work was undertaken to understand microstructure development in this zone and how the ICCGHAZ may affect the overall performance of the HAZ.

Gleeble thermomechanical simulations have been conducted to produce bulk samples representative of different welding scenarios. Charpy impact tests and tensile tests have been performed over a range of temperatures. It was found that when a continuous necklace of martensite-austenite islands form on the prior austenite grain boundaries (i.e. for a M/A fraction of ≈10%), the Charpy impact toughness energy is dramatically decreased and the ductile brittle transition temperature is significantly raised. Detailed studies on the secondary cracks have been conducted to examine the fracture mechanisms in the different microstructures. The results show that the lower bainite microstructures obtained after the 1st thermal treatment, representative of CGHAZ have excellent impact properties. The impact toughness of the microstructures typical of ICCGHAZ is strongly dependent on the composition as well as morphology and spatial distribution of the resulting martensite-austenite (M/A) islands transformed from inter-critically formed austenite. This zone can play a significant role in fracture initiation and thus needs to be considered in alloy and welding process designs.
New Leak Location Approaches for Gas Pipelines Using Acoustic Waves
Authors: Liu Cuiwei , Li Yuxing , Hu Qihui , Wang Wuchang , Wang Yazhen , Li Xuejie , Xu Minghai
Published: November 2018

Natural gas is a vital energy carrier which can serve as an energy source, which is extremely vulnerable to leakages from pipeline transportation systems. The required ignition energy is low. Although the safety of natural gas pipelines has been improved, the average economic loss of natural gas accidents, including leaks, is large. To solve these problems, an acoustic leak localization system is designed and researched for gas pipelines using experiments with methods proposed according to different application situations. The traditional method with two sensors installed at both ends can be improved by a newly proposed combined signal-processing method, which is applied for the case that it is necessary to calculate the time differences with data synchronicity. When the time differences cannot be calculated accurately, a new method based on the amplitude attenuation model is proposed. Using these methods, the system can be applied to most situations. Next, an experimental facility at the laboratory scale is established, and experiments are carried out. Finally, the methods are verified and applied for leak localization. The results show that this research can provide a foundation for the proposed methods. The maximum experimental leak localization errors for the methods are −0.592%, and −7.62%. It is concluded that the system with the new methods can be applied to protect and monitor natural gas pipelines.
EMAT As a Basis for a Comprehensive System Wide Crack Management Program
Authors: Katz David , Potts Steve , Beuker Thomas , Grillenberger Jörg , Weber Ralf
Published: November 2018

The integrity of aging assets like gas pipelines are managed by a variety of inspection and validation methods. In the particular case of gas pipelines and their susceptibility to cracking, an ultrasonic inspection methodology has been introduced over the last decade, which is based on an electromagnetic acoustic transducer (EMAT). Meanwhile, a high resolution implementation of the technology has been utilized on in-line inspection (ILI) tools from 10″ to 48″ in diameter. Williams Gas Pipelines have utilized this inspection technology successfully on several pipelines, therefore an overview will be given about this experience. Secondly a case study will be presented, in which a post hydrostatic test ILI service was used to gain additional relevant safety and integrity information from the ILI inspection and to better understand the actual capabilities of a hydrostatic test. The approach taken is in accordance with API 1163 and in consideration of API 1176. As part of this approach the performance of the ILI tool was confirmed based on a set of full scale tests conducted at the PRCI ILI test facility. The results were used to increase the statistical confidence in the capabilities of the technology.
Effect of Room Temperature Creep on Hydrostatic Leak Test
Authors: Zand Benjamin B. , Steiner Adam
Published: November 2018

Because of the stochastic nature of line pipe characteristics a small percentage of the pipe joints in a given pipeline may possess actual yield strengths below the specified minimum yield strength. During a hydrostatic test these segments may experience some plastic deformation as the hoop stress approaches the yield point. It is well known that the effect of room temperature creep near the yield becomes notable and therefore can affect pressure trending during the hold period (leak test). In this work a numerical model is developed for the analysis of creep deformation. A conceptual study is carried out to demonstrate potential effects of creep on hydrostatic test pressure trending during a leak test. This analysis can help operators understand the potential effects of creep and distinguish it from other factors such as temperature changes or leakage and can help identify, or rule out, the occurrence of pipe yielding during hydrostatic tests.
Do We Need a Safe Excavation Pressure for Dented Pipelines: How Should it Be Defined?
Authors: Kainat Muntaseer , Langer Doug , Hassanien Sherif
Published: November 2018

Pipeline operators’ utmost priority is to achieve high safety measures during the lifecycle of pipelines including effective management of integrity threats during excavation and repair processes. A single incident pertaining to a mechanical damage in a gas pipeline has been reported previously which resulted in one fatality and one injury during investigation. Some operators have reported leaking cracks while investigating rock induced dents. Excavation under full operating pressure can lead to changes in boundary conditions and unexpected loads, resulting in failure, injuries, or fatalities. In the meantime, lowering operating pressure during excavation can have a significant impact on production and operational availability. The situation poses two conflicting objectives; namely, maximizing safety and maximizing operational availability. Current pipeline regulations require that operators have to ensure safe working conditions by depressurizing the line to a level that will not cause a failure during the repair process. However, there are no detailed guidelines on how an operator should determine a safe excavation pressure (SEP) level, which could lead to engineering judgment and subjectivity in determining such safety level. While the pipeline industry relies on well-defined fitness for purpose analyses for threats such as crack and corrosion, there is a gap in defining a fitness for purpose for dents and dents associated with stress riser features in order to set an SEP. Stress and strain based assessment of dents can be used in this matter; however, it requires advanced techniques to account for geometric and material nonlinearity. Additionally, loading and unloading scenarios during excavation (e.g. removal of indenter, overburden pressure, etc.) drive a change in the boundary conditions of the pipe that could lead to leakage. Nevertheless, crack initiation or presence within a dent should be considered, which requires the incorporation of crack geometry and application of fracture mechanics in assessing a safe excavation pressure. Recently, there have been advancements in stress and strain based finite element analysis (FEA) of dents coupled with structural reliability analysis that can be utilized to assess SEP. This paper presents a reliability-based approach to determine a safe excavation pressure for dented liquid pipelines. The approach employs nonlinear FEA to model dents interacting with crack features coupled with uncertainties associated with pipe properties and in-line-inspection information. A fracture mechanics-based limit state is formulated to estimate the probability of failure of dents associated with cracks at different levels of operating pressure during excavation. The application of the developed approach is demonstrated through examples within limited scope. Recommended enhancements and future developments of the proposed approach are also discussed.
Influence of Material Heterogeneity on the Strain Capacity of Pipelines
Authors: Höhler Susanne , Mondry Andreas , Kalwa Christoph , Samadian Kaveh , De Waele Wim , Hertelé Stijn
Published: November 2018

The strain capacity of pipes under combined loading is an important research topic within strain-based design. While strain capacity equations assume homogeneous pipe material properties, a realistic pipeline shows scatter in mechanical properties. Test and simulation programs have indicated that this “pipe heterogeneity” may reduce the tensile strain capacity under uniaxial loading by a factor up to two. To date, its effect in other scenarios (compressive; combined internal pressure and axial plastic deformation) has received little attention. To investigate these scenarios and compare them with uniaxial tensile loading, Europipe, Salzgitter Mannesmann Forschung (SZMF) and Soete Laboratory, UGent have set up a large-scale test program on UOE pipe X70 (OD = 1219 mm, WT = 17.5 mm), comprising a full-scale pressurized bend test and curved wide plate tension tests. All tested welds joined pipes with nominally equal pipe grade from the same pipeline project, with strongly different actual properties. Optical full field strain measurements by means of digital image correlation reveal local effects of pipe heterogeneity on the strain distribution in the vicinity of the girth weld. All tests showed pronounced degrees of non-uniformity in strain development, in some cases even inhibiting plastic deformation in the stronger material as its weaker counterpart collapses. Implications of the observations with respect to strain-based design are discussed.
Advanced EMAT Crack Tool for Unpiggable Pipelines
Authors: Bondurant Phillip , Farrag Khalid , Kannajosyula Haraprasad , Droessler Maureen , Mactutis Tony
Published: November 2018

This paper presents the development and testing of an Electro-Magnetic Acoustic Transducer (EMAT) sensor prototype to detect and quantify longitudinal cracks in small diameter and difficult to inspect or unpiggable gas pipelines. The development of the system was a collaborative and jointly-funded work between Quest Integrated, Gas Technology Institute, Operations Technology Development, and US DOT, Pipeline Hazardous Material Safety Admin (PHMSA).

The initial focus for the project was to inspect 8-inch (200 mm) diameter pipes with robotic or tethered towing, with the eventual goal of a free-swimming tool. A bench scale lab prototype has been successfully completed and tested in Phase 1 of the project in 2016. The prototype demonstrated the basic approach of a EMAT tool for crack detection and sizing that could be packaged into a single module, had reasonable flaw depth sensitivity, was bidirectional, and could negotiate a 1.5 D bend.

Phase 2 focused on identifying and solving additional implementation issues, developing a more hardened tool for field pull testing, improving flaw sizing, and the necessary internal electronics and processing algorithms. The prototype recently developed in Phase 2 was tested in an extended length of 8-inch diameter steel pipe with pre-set and controlled longitudinal cracks. The results demonstrated the applicability of the integrated prototype in locating and sizing multiple flaws in the axial direction.

This paper discusses the EMAT sensor development and results of the laboratory testing program.
Coupling Metallurgy and Manufacturing Parameters of Pipeline Fittings to Avoid Substandard Properties
Authors: Fazeli Fateh , Scott Colin , Saragosa James , Cicoria Robert , Fraser Jim
Published: November 2018

High strength, butt-welded pipeline fittings are critical components for the construction of reliable and safe pipeline systems to extract, gather and transmit oil and gas products. Due to stringent safety and environmental requirements, fittings manufacturers are obliged to adhere to commonly accepted industry standards (e.g. CSA Z245.11, MSS-SP-75) and adopt supplementary operators’ specifications. Nevertheless, there have been several recent cases where fittings delivered by qualified manufacturers and available through local stock suppliers have not met the specified tensile properties, such that they failed during hydrostatic pressure tests or in-service operations. The issue has triggered concerns of operators and regulators (e.g. NEB SA 2016-01) warning about the use of substandard fittings. Although deficiencies in engineering design or operation beyond permissible conditions could be contributing factors, the root cause of the recent fittings failures was mainly associated with the underlying metallurgy and processing resulting in critically low yield strength and/or toughness levels. Further, existing standards and specifications are not stringent enough to screen out fittings with inadequate steel composition or improper manufacturing parameters. As such, a comprehensive modelling and experimental study has been launched to understand the interplay between the composition, grade, geometry and plant-specific processing parameters of quenched and tempered pipeline components. The experiment entailed plant trials using an instrumented NPS 36″ 3D elbow to measure the actual thermal response of the fitting during reheating, quenching and tempering cycles. Data was acquired from 36 different positions on the part in order to monitor any deviations from intended production parameters. Further, the metallurgical behaviour of the base steel plate, in terms of austenite grain growth, continuous cooling transformations (CCT) and temper softening of the as-quenched microstructure, has been established by dilatometric tests and microstructural characterization. The analysis and coupling of these diverse data sets is not trivial and requires scientific-based computational modelling. An integrated thermal-structure-properties finite element model was developed to predict the temporal and spatial evolution of the microstructure and provide a 3D strength map for any as-quenched and as-tempered fitting. This predictive engineering tool aids the selection of adequate steels and suitable heat treatment parameters such that target gauges and grades can be manufactured by a given plant to meet the specified requirements and standards. This paper describes the aforementioned methodology and highlights the challenges associated with the manufacture of fittings; in particular thick-wall pipeline components. Further, guidelines and existing knowledge gaps for improved specifications and standards will be discussed.
Verification of Applicability of Battelle Two-Curve Method to Ultrahigh-Pressure Rich-Gas Pipelines Based on a Full-Scale Burst Test
Authors: Imai Yasuhito , Mitsuya Masaki , Toyoda Masao
Published: November 2018

A full-scale gas burst test was conducted to confirm the behavior of unstable ductile crack propagation and arrest and to confirm the required toughness value to prevent unstable ductile fracture under an ultrahigh pressure of 18 MPa. A full-scale test was conducted at the Spadeadam test site in the UK for unburied pipes. The test pipes used in this test were of API 5L Grade L450 with outer diameter of 610 mm and thickness of 17.5 mm. The toughness of the test pipes increased away from the center, where an explosive charge was placed across the top of the girth weld for crack initiation. The gas used in the test consisted of ∼89% methane and other heavy hydrocarbon gas components, and the test temperature was 0 °C. A gas circulation loop was constructed to ensure that a homogeneous gas mixture and temperature were achieved throughout the test rig.

In addition to dynamically measuring the ductile crack velocity and decompression behavior of the rich gas, as has often been done in previous burst tests, the circumferential distribution of the decompression behavior was measured using circumferentially placed pressure transducers. Furthermore, the fracture strain near the propagating crack was measured.

The initiated unstable ductile crack was arrested in the third pipe. From the material properties of the test pipes in which the unstable ductile crack was arrested, the required Charpy absorbed energy and DWTT absorbed energy to prevent unstable ductile fracture in unburied pipes were obtained. In addition, the above data can be useful for validating numerical models that evaluate the propagation/arrest of unstable ductile fracture.

The required Charpy and DWTT absorbed energy values obtained in this test were compared with those predicted by the Battelle Two-Curve Method (BTCM). As noted in previous studies, it was confirmed that the BTCM underestimates the required Charpy absorbed energy and requires a certain correction factor for precise evaluation, whereas the DWTT absorbed energy predicted by BTCM was consistent with the experimental result.
Do You Have Wrinkles? A Strain- and Stress-Based Approach for the Assessment of Wrinkles Reported by In-Line Inspection
Authors: Holliday Chris , Wynne Dominic , Clyne Alasdair , Wilde Andrew
Published: November 2018

Improvements in in-line inspection (ILI) technology have led to an increase in the probability of detection and ability to characterize geometric features such as wrinkles, the assessment of which was introduced into CSA Z662, “Oil & Gas Pipeline Systems”, in the 2015 version.

The CSA wrinkle acceptance limits are based predominantly on fatigue assessment criteria; part of the assessment procedure is confirmation that wrinkles are free from associated cracking. In practice, this often restricts the assessment to wrinkles that have already been investigated in-field and where the absence of cracking has been confirmed by non-destructive examination (NDE).

This paper describes the assessment of a series of wrinkles that exceeded the CSA height criteria, reported by ILI within field bends in an insulated liquid pipeline. Strain-based assessment, supported by in-field investigations, was used to investigate the likelihood of associated cracking.

Utilizing the high resolution caliper ILI tool data, three-dimensional profiles of the wrinkles were generated. Previous work that compared “tool-measured” with “field-measured” profiles identified that caliper tool measurements can underestimate the true depth and profile of wrinkles, this effect is more pronounced for particularly sharp wrinkles. The wrinkle profiles were therefore adjusted based on the historical field-tool correlation. Strain profiles were then calculated using the guidance within ASME B31.8 Appendix R. It was identified that the majority of the wrinkles exceeded the 6% strain limit commonly applied to dents.

One field bend containing multiple wrinkles was subsequently excavated in order to gather detailed profile information and to inspect for cracking. Upon excavation, the wrinkles were not visually apparent, but their presence was confirmed following removal of the insulating coating. Profile information was subsequently recorded using laser scanning technology. In addition, NDE confirmed the absence of cracking, despite the fact that the majority of wrinkles were associated with strain levels that exceeded the CSA limiting value, 6%. The laser scan data were then compared with the adjusted “tool-measured” profiles. It was observed that the adjusted measurements based on the ILI tool data were conservative, and in some cases excessively so. The caliper measurements were optimized by identifying a factor that could be systematically applied to the “tool-measured” wrinkle profiles, which provided consistency with the profiles measured by the laser scan, thereby improving the accuracy of the dimensions and strain estimation of the remaining (non-excavated) wrinkles.

Finally, a S-N based fatigue assessment was performed using operational cyclic pressure data and estimates of the stress concentration factors associated with the wrinkles. The calculated fatigue lives exceeded the expected operational life of the pipeline.
Real-Time Continuous Pipeline Integrity Monitoring Utilising Telecommunications Optical Fibre Cables
Authors: Hayward Peter J. , Fryer Tom A.
Published: November 2018

A recent trend in the field of pipeline monitoring has been the utilisation of an optical fibre based distributed acoustic sensing (DAS) technology, for the purpose of security monitoring of buried pipelines [1–3]. The technology comprises an interrogator, connected to an optical fibre cable, which is interrogated to acquire coherent Rayleigh backscatter. Localised environmental vibrations may result in a proportional strain of the fibre. This strain results in a localised optical path length variation, resulting in a phase distortion in the measured signals. Application of signal processing techniques infer the characteristic of the originating stimulus, and thus identify and locate the source activity of interest. Activity may arise as a result of ground excavation, vehicular movement, or similar in the vicinity of the pipeline.

Researchers are now studying the possibility of utilisng this technology for the purpose of pipeline leak detection monitoring [4]. This paper provides a review of one such programme of work.

Results are presented for a permanent installation, where signatures relating to leaks were identified, and located in the resulting DAS data. Results are provided relating to liquid leaks, where product was emitted at a flow rate of 20.0l/minute and operational pressure 20.0bar.
Calibration of a Nondestructive Toughness Tester (NDTT) for Measuring Fracture Toughness of Pipeline Steel
Authors: Palkovic Steven D. , Bellemare Simon C. , Botros Kamal K. , Chen Xiande (Derek) , Kania Richard
Published: November 2018

In-ditch/in-service characterization of pipelines using nondestructive evaluation (NDE) can provide valuable data for confirming operating pressure and qualifying pipelines for transporting natural gas of different quality or gas mixture, as well as for determining repair criteria for integrity management programs. This is especially relevant for vintage pipelines that may not have material test reports (MTR) available, and for aging infrastructure that have been subjected to suspected or unknown integrity threats. However, measurement of material fracture toughness currently requires the removal of large samples for laboratory testing, such as compact tension (CT) fracture testing or Charpy impact testing. The present work introduces a new concept, the Nondestructive Toughness Tester (NDTT), that provides a NDE solution for measuring the fracture toughness of pipeline steel in a superficial layer of material (∼0.005 inches). The NDTT uses a specially designed wedge-shaped stylus to generate a Mode I tensile loading that results in a ductile fracture response. NDTT tests are performed in multiple orientations on 8 different pipeline steel samples covering 3 different grades to compare the NDTT material response with the fracture toughness measurements from laboratory CT specimens. Analysis of these results indicate that the height of a fractured ligament that remains on the sample surface after NDTT testing exhibits a linear relationship with traditional CT J-integral measurements normalized by its yield strength. This type of behavior is analogous to the crack-tip-opening-displacement (CTOD) calculated through elastic-plastic fracture mechanics. Tests conducted on the pipe outer diameter and in the longitudinal direction near the pipe mid-wall indicate that the NDTT can measure differences in fracture toughness for different crack orientations. Furthermore, the results show that outer diameter tests provide a conservative estimate of the overall steel fracture toughness. These observations indicate that the NDTT is a viable method for assessing toughness properties of steel materials. Additional research is required to further refine the implementation of the NDTT concept and understand the relationship with laboratory test results on pipe cutouts, but the progress is already a significant step towards obtaining additional material toughness data for integrity management.
Crack Shape Development for Leak-Before-Break Analysis in Pipelines
Authors: Zhang Kathy , Xu Luyao , Ferguson James , Zadery Dennis
Published: November 2018

Surface cracks in pipelines under certain service conditions may grow due to fatigue, which is caused by pressure (cycles). The leak-before-break (LBB) assessment method is employed to avoid any catastrophic failure prior to a detectable leakage. In the LBB analysis, crack critical length is an essential element for determining the pipeline leak or rupture.

The common approach regarding the evaluation of LBB is to calculate the critical crack length and through-wall length under iven pressure cycling conditions. If the critical crack length is less than the through-wall length, LBB conditions could occur and be detected if leak detection capability is high. This involves complex calculations in crack fatigue growth and could result in extensive analysis if thepipeline has a large crack population.

This paper presents a simplified approach for assessing the leak-before-break of the flawed pipelines. This approach is based on industrial code API 579-1/ASME FFS-1 Fitness-For-Service. Through the investigation of effects for different parameters on crack growth, including crack initial geometry, pipeline materials, loading conditions, pipeline diameter and wall thickness, it was determined that the crack initial aspect ratio is a major factor influencing crack growth and geometry evolution. Based on these parameters, a crack fatigue growth map was developed. By comparing the behaviors of different cases, it was confirmed that the proposed method is a valid approach for the pipeline LBB analysis.
Are Integrity Management Programs Making a Difference?
Authors: Paviglianiti Joe , Murray Alan , Elabor Tijani (TJ)
Published: November 2018

As a result of numerous stress corrosion cracking incidents in the 1980s and early 1990 the National Energy Board (NEB) held an Inquiry1 in 1995 on the SCC failure mechanism and how to prevent failures. One of the recommendations of the Inquiry was Companies were to develop a SCC management program to proactively identify and mitigate SCC. Based on the apparent success of the SCC programs in significantly reducing SCC failures, the NEB revised its Onshore Pipeline Regulations in 1999 (OPR-99)2 to require companies to develop an integrity management program (IMP) for all hazards.

This paper discusses the evolution of integrity management program (IMP) requirements and evaluates incident rates and other performance metrics to determine if there is evidence that IMPs have contributed to the improvement of safety of pipelines. The paper highlights the challenges associated with gathering incident and IMP performance metrics and evaluating the data to determine if there is a correlation between the implementation of IMP and pipeline safety. In addition, the analysis discusses the challenges associated with comparing data between different countries and regulatory jurisdictions. Suggestions for future improvement are identified.
Achieving North American Record for Longest Intelligent Inspection of a Natural Gas Pipeline
Authors: Epur Sheshi , Schartner Aaron , Sander Frank
Published: November 2018

TransCanada was faced with a significant challenge to inspect a 941 km NPS 48 pipeline. The options for the inline inspection (ILI) were multiple segments which would cause an increased cost with new pigging facilities required and a delay to the ILI schedule or attempt to pig the longest natural gas pipeline section in North America. The extraordinary proposal would require a massive 48″ combination Magnetic Flux Leakage (MFL) tool to traverse a high-speed gas pipeline 941km from Burstall, Saskatchewan to Ile des Chenes, Manitoba, Canada. Given the alternative of the installation of 3 additional launcher and receiver stations and the risk to overall project schedule from extended inspection operations, TransCanada took the bold decision to perform an MFL inspection in a single pass. However, as expected, this option created a new set of challenges to guarantee first run success in one of the harshest environments for an ILI tool and in a line where the cleanliness condition was unknown. This last factor, was a critical concern as the volumes of debris that could be collected with the highly aggressive MFL tool brushes, could easily and very quickly have led to very significant debris build up during inspection that at best would likely cause degraded data leading to an unwanted re-run and at worst the possibility of a stuck pig and subsequent retrieval program. From a project perspective either occurance was considered to be mission critical — if either occurred there was no easy solution to collecting the much needed condition data of the pipeline. In July 2017, a successful VECTRA HD GEMINI inspection was completed. This paper discusses the main program risks, mitigation steps taken over and above a standard ILI run. Key considerations and actions taken relating to additional engineering and tool modifications to various components of the inspection vehicle itself will be discussed. Lastly, insight will be given into an extensive smart cleaning program developed with the ILI vendor, using a combination of mechanical cleaning associated and debris level assessment, specifically designed and tailored for the project to ensure that the pipeline was both ready for ILI and that cleaning had reached optimum for ILI so that full, high quality MFL data would be collected the first time.
Preserving Pipeline Integrity With Large Diameter Stone Columns at Dead Horse Creek Crossing, Southern Manitoba, Canada
Authors: Wong Wing-Keat (Wayne) , Wiebe Brad , Treen Curtis , Richmond John
Published: November 2018

Pipeline integrity has been threatened at the Dead Horse Creek pipeline crossing in southern Manitoba by a slow-moving slope failure with a potential for crest retrogression. The movement zone extends from the slope crest to the bottom of the creek, a vertical distance of about 25 m and is approximately 80 m long from toe to scarp and 100 m wide along the creek. The slope has degraded over time and is controlled by the combination of local geology, which consists of weak colluvium overlying high plastic clay shale, and creek bank erosion and channel degradation. Saturated soil conditions, a function of poor drainage and elevated seasonal precipitation, have exacerbated the problem over the years.

The slope movements have been monitored on a regular basis since 2008 and presented an increasing risk to the integrity of multiple pipelines located in two rights-of-way (ROWs) situated within and immediately adjacent to the failing soil mass. The site is surrounded by various infrastructure and recreational areas that are key to the community, and therefore is considered a high consequence area with respect to potential pipeline failures. To manage the risk and protect pipeline integrity, various stress relief and other mitigating measures have been implemented since 2013 [1], culminating in a major slope rehabilitation project undertaken in 2015, which comprised earthworks, drainage and watercourse improvements, and slope stabilization using stone columns.

While the use of stone columns to stabilize embankments is not a new technique, it is not commonly used in the pipeline industry and represents another option for geohazard stabilization in the right situations. This paper presents the slope stabilization techniques employed and discusses the challenges of working on an active moving slope confined by a watercourse and live pipeline assets. The positive benefits of the stabilization measures are illustrated through the use of 2D and 3D numerical modelling, and confirmed through an ongoing geohazard management program that includes site inspection and instrumentation monitoring which continues to show improvements in slope performance post construction.
Implementing API RP 1173, Pipeline Safety Management Systems: Tools and Resources to Facilitate Industry Implementation
Authors: Duke Aaron , Murk Dave , Byrd Bill , Saulters Stuart
Published: November 2018

Since the publication of API Recommended Practice (RP) 1173: Pipeline Safety Management Systems, in July 2015, the energy pipeline trade groups in North America (API, AOPL, AGA, INGAA, APGA and CEPA) have worked collaboratively to develop tools and programs to assist energy pipeline operators with the development and implementation of appropriate programs and processes. These resources include a Planning Tool, Implementation Tool and Evaluation Tool, as well as a Maturity Model that describes a continuum of implementation levels. The Planning Tool is used to compare an operator’s existing management system to the RP requirements and develop action plans and assign responsibilities to close gaps. It is intended to help operators achieve Level 1 maturity (develop a plan and begin work). The Implementation Tool is used to evaluate and summarize implementation status by question, element and overall, and helps track development of program implementation to Level 3 maturity. The Evaluation Tool plays two key roles addressing the conformity and effectiveness of the system. This tool is used to assess and report the level of conformity to the requirements, the “shall” statements, of the RP and possible Level 4 maturity. The Evaluation Tool also provides the means to appraise the effectiveness of an operator’s programs in achieving the objectives of the RP, asking the key question, “Is the system helping and driving improvement?” These resources can be supplemented by the voluntary third-party audit program developed by API and the Peer-to-Peer sharing process.
Instructive Value of Flow Assurance Assessment Based J-Curve Analysis on Pipeline Maintenance and Operation
Authors: Cheng David
Published: November 2018

This paper develops an optimization concept based on J-curve analysis in pipeline system design as a tool in the quantitative evaluation of pipeline operation efficiency and maintenance decisions. The method includes the creation of the J-curve (total Capex and Opex per unit volume versus the pipeline flow rate) of the as build system without maintenance, the improvement or changing of the J-curve after maintenance goal is achieved, and the return of expenditure curve of the maintenance at different flow rate based on the current commodity market price. The J-curve improvement and the return of expenditure curve will show the efficiency of the maintenance activities as basis for their priority and necessity. The return curve also help to set up the range of optimized flow rates that the pipeline should be operated at given the market price status. The creation of J-curve is based on the pipeline performance hydraulics model bench marked with pipeline measurement data.
The Future of In-Line Inspection: Free-Floating Smart Sensors
Authors: van Pol Anouk , van Pol John , McNealy Richard , Goudy Clay
Published: November 2018

Advances in micro-electronics and machine learning open the door to a new method of in-line pipe inspection: small free-floating smart sensors moving in the flow, capturing critical data and enabling operators to optimize pipeline performance, detect anomalies, and flag changes in pipeline condition.

The free-floating nature of these smart sensors allows for full length pipeline inspection without interrupting the operation. This makes frequent inspection possible turning it into a cost-efficient data driven solution. The alternative requires significant capital to modify the pipeline system to accommodate traditional ILI. Furthermore, traditional ILI methods are a one off costly and labor extensive measurement executed once every 5 to 10 years, where these free-floating sensors allow for high frequency, low cost measurements.

Frequent inspection allows for early detection of changes in the pipeline condition such as deposit formation and metal loss as well as timely detection and localization of leaks or similar hazardous conditions. The free-floating nature, combined with the capability to detect pipeline elements such as flanges and welds, permits accurate localization without the need for external markers.

An alternative to the free-floating deployment, the sensor device can also be attached to an off-the-shelf cleaning pig. This solution is especially suited for gas lines and allows for screening of the pipeline condition while cleaning the pipeline with limited extra effort from the operator.

The paper will demonstrate the outcome of over ten validation projects that have been conducted during the course of 2017 using an implementation of this technology in a golf ball-sized (1.5 inch diameter), robust and chemically inert integrated sensor system called Piper™. The Piper™ is equipped with a comprehensive set of sensors, consisting of a 3-axial accelerometer, gyroscope and magnetometer, a combined pressure and temperature sensor, and an advanced system for acoustic leak detection.

Topics that will be addressed include the advantage of using a free-floating integrated device, the capability of reconstructing positioning, the ability to locate and quantify leaks, and the ability to locate pipeline elements such as welds and flanges, and changes in wall thickness. In the Piper™ pig combination, the detectability of bends including the angle and radius of curvature will also be demonstrated.
Satellite Data Analytics for Natural Disaster Assessment and Application to Pipeline Safety
Authors: Piazza Mark , Gregorian Karineh , Robert Gillian , Svacina Nicolas , Gamble Lesley
Published: November 2018

Understanding where, when, and how conditions are changing along the extent of an energy pipeline system, which can be vast, is a challenging task. The challenge can be even greater when natural disasters1 create a condition where access to affected pipelines, qualified personnel, and equipment is limited.

To address these challenges, pipeline operators are working directly with experts in satellite technology to develop innovative applications incorporating the use of satellite technology and analytical processes to improve natural disaster monitoring and response. Through recent experiences following Hurricane Harvey in the Gulf Coast region of the United States in August-September 2017 and the wildfires and mudslides in Southern California that occurred in December 2017 to January 2018, space-borne Synthetic Aperture Radar (SAR) satellite data was shown to be a useful tool for wide-area monitoring. Satellite-based SAR imagery has the unique advantage of penetrating through cloud cover and smoke and is capable of providing an early view of the extent of damage in both conditions.

Satellite data and continuous improvements to their derived analytical products have resulted in significant benefits for pipeline operators preparing for and responding to the effects of potentially damaging natural processes, including river scour, erosion, avulsion, mudslides, and other threats to pipeline integrity and public safety. SAR change detection algorithms and processes can provide effective results in identifying areas affected by natural disasters that are not readily available by other means. These methods also provide timely information for allocating and directing resources to the most critical locations in support of post-disaster assessment and analysis. SAR satellite data and Amplitude Change Detection (ACD) algorithms provided the basis for confirming where flooding near pipeline infrastructure was most substantial following Hurricane Harvey. In the case of the Southern Californian forest fires and mudslides in Ventura and Santa Barbara counties, recent investigations into ACD and Coherence Change Detection (CCD) algorithms showed promising results, providing a detailed view of damaged areas in near-real time.

This paper describes the process of collecting, analyzing, and applying satellite data for assessing the impacts of natural disasters on pipeline infrastructure, and the methods applied, consisting primarily of multiple change detection algorithms, that are used to process the large volume of satellite archive images to extract relevant changes. This paper also describes how these tools and products were practically applied to support decisions by pipeline operators to protect and ensure the integrity and safety of pipelines in the affected areas.
Ultrasonic NDE Technology Comparison for Measurement of Long Seam Weld Anomalies in Low Frequency Electric Resistance Welded Pipe
Authors: Torres Luis , Fowler Matthew , Bergman Jason
Published: November 2018

In the pipeline industry, a widely accepted methodology for integrity crack management involves running ultrasonic In-Line Inspection (ILI) technologies. After an ILI tool run is completed, the performance of the tool is typically validated by excavating the pipeline and conducting in-the-ditch investigations. Ultrasonic Non-Destructive Evaluation (NDE) techniques are used in the field to characterize and measure crack-like features. These in-the-ditch measurements are compared back to ILI results in order to validate tool performance and drive continuous technology improvements. Since validation of the ILI tool relies on NDE measurements, acquiring accurate and representative data in the field is a critical step in this integrity crack management approach. Achieving an accurate field inspection comes with its challenges, some of which relate to complex long seam weld conditions present in older vintage pipelines including: weld misalignment, weld trim issues, and dense populations of manufacturing anomalies. In order to better understand the challenges associated with complex long seam weld conditions, an evaluation and comparison of the performance of NDE technologies currently available was conducted.

In this study, a portion of a Canadian pipeline with complex long seam weld conditions was cut-out and removed from service. Multiple NDE crack inspection technologies and methods from three different vendors were used to assess the condition of the long seam weld. Conventional Ultrasonic Testing (UT), Phased Array Ultrasonic Testing (PAUT), Time of Flight Diffraction (TOFD), and variations of Full Matrix Capture Ultrasonic Testing (FMCUT) were used to assess the long seam weld and their results were compared. The performance of all NDE technologies is baselined by comparing them with destructive examination of sections of the long seam weld. The newer NDE assessment methodologies were shown to be consistently more accurate in characterizing long seam features.