bluuebunny/crossref_metadata_2025 huggingface dataset:
An Internet of Things (IoT) Project Based on a Text Messaging (SMS) Gateway Applied to a Pipeline SCADA System
Authors: D. Bezerra Marco Antonio , Cabral Mateus da C. S. , Santiago Edson R.
Published: November 2018

The present work arose from problems occurred during the revamp of a pipeline SCADA (Supervisory Control and Data Acquisition) system at the beginning of 2012, when occurred some unexpected system crashes that could interrupt the operation of the second major Brazilian pipeline maritime terminal.

Before a system breakdown, we observed some signs, like fail-overs in the event log files. If the development and maintenance crews were aware of these events not only the problem causes could be better understood, but also the imminent crash could have been avoided. A faster and autonomous way for the system communicates its problems was necessary.

ACARS (Aircraft Communications Addressing and Reporting System) — a part of an autonomous communication system, which reports aircraft condition for a system on the ground, through satellite links and short messages — inspired us to develop an Internet of Things (IoT) system, using text messages (SMS, short message service) of the Global System for Mobile Communications (GSM).

Autonomous and short text messages are the keywords that drove our work, and the solution came through a text message gateway — the solution to get information in advance.

This presentation will discuss the idea, hardware and software components, message format, applications and future perspectives.
Corrosion Growth Modeling Based on Mass In-Line Inspection Data Using Variational Inference
Authors: Birkland Monica , Dann Markus R.
Published: November 2018

In-line inspection (ILI) data is commonly used in corrosion growth models (CGMs) to predict the corrosion growth in energy pipelines. A hierarchical stochastic corrosion growth model is considered in this paper which considers the variations in the corrosion growth, both spatially and temporally, the inherent measurement error of the ILI tools as well as the model uncertainties. These uncertainties are represented as unknown model variables and are often inferred using a Bayesian method [1], [2] and samples of the unknown parameters’ posterior probability density functions (PDFs) are obtained using Markov Chain Monte Carlo (MCMC) sampling techniques [3].

ILIs can result in massive data sets. In order for MCMC-based inference techniques to yield reasonably accurate results, many samples (approaching infinity) are required. This fact in addition to the massive data sets exponentially increases the scale of the inference problem from an attainable solution to a potentially impossible one that is limited by today’s computing power. For this reason, MCMC-based inference techniques can become inefficient in the cases where ILI datasets are large. The objective is to propose variational inference (VI) as an alternative to MCMC to determine a Bayesian solution for the unknown parameters in complex stochastic CGMs. VI produces approximations of the posterior PDFs by treating the inference as an optimization problem. Variational inference emerged from machine learning for Bayesian inference of large data sets; therefore, it is an appropriate tool to use in the analysis of mass pipeline inspection data[4]–[7].

This paper introduces VI to solve the inference problem and provide a solution for a hierarchical stochastic CGM to describe the defect-specific corrosion growth experienced in pipelines based on excessively large ILI datasets. To gauge the accuracy of the VI implementation in the model, the results are compared to a set of values generated using a stochastic gamma process that represents the corrosion growth process experienced by the pipe.
Next Generation Ductile Fracture Arrest Analyses for High Energy Pipelines Based on Detail Coupling of CFD and FEA Approach
Authors: Botros K. K. , Clavelle E. J. , Uddin M. , Wilkowski G. , Guan C.
Published: November 2018

Axial ductile fracture propagation and arrest in high energy pipelines has been studied since the early 1970’s with the development of the empirical Battelle Two-Curve (BTC) model. Numerous empirical corrections on the backfill, gas decompression models, and fracture toughness have been proposed over the past decades. While this approach has worked in most cases, the dynamic interaction between the decompression of the fluid in the vicinity of the crack tip and the behaviour of the pipe material as it opens to form flaps behind the crack has been very difficult to solve from a more fundamental approach. The effects of the pressure distribution on the flap inner surface making up the crack-driving force which drives the crack propagation speed has been suggested in the past, but due to intensive computational effort required, it was never realized. The present paper attempts to tackle this problem by employing an iterative solution procedure where the gas pressure field in the vicinity of the crack tip is accurately solved for by computational fluid dynamics (CFD) for a given flap geometry determined from a dynamic FEA model to render a new flap geometry. In this model a cohesive-zone element at the crack tip is employed as a representation of the material toughness parameter. The final outcome is the determination of the cohesive energy in the FEA (as a representation of the material toughness parameter) to match the measured fracture propagation speed for the specific case. A case study was taken from full-scale rupture test data from one of the pipe joints from the Japanese Gas Association (JGA) unbackfilled pipe burst test data conducted in 2004 on the 762 mm O.D., 17.5 mm wall thickness, Gr. 555 MPa (API 5L X80) pipe.
Transverse Strain Aging Behaviour of Uncoated Thick Walled X70 UOE Microalloyed Steel Pipes
Authors: Wiskel J. B. , Ma J. , Ivey D. G. , Henein H.
Published: November 2018

Transverse tensile samples were extracted from the centreline position of three different compositions of uncoated thick walled microalloyed X70 UOE pipe at a location 180° from the weld. Aging heat treatments of 5, 15, and 25 minutes and temperatures of 175, 215, and 255°C were applied. Tensile tests were conducted on both the original pipe and on pre-strained samples. Microstructural analysis was undertaken using optical microscopy and scanning electron microscopy (SEM). The effects of a combined time and temperature aging parameter, pre-strain, microstructure and tensile work hardening behaviour on the pipe yield stress and yield to tensile strength ratio, is presented.
Assessment of Stress Based Design Pipelines Experiencing High Axial Strains
Authors: Andrews Robert , Stephens Mark , Carr Malcolm , Brückner Johannes
Published: November 2018

Strain based design concepts have been extensively used for subsea pipelines for both installation and service. However, most onshore transmission pipelines are designed assuming a maximum longitudinal stress, typically 90% SMYS. Some onshore pipelines have been designed for a limiting axial strain generated by causes such as seismic activity, frost heave, discontinuous permafrost or landslides. Models have been developed to predict the axial strain capacity in both tension (usually limited by the girth welds) and compression (where the limit is local buckling of the pipe wall).

In service monitoring of a pipeline initially designed on a stress basis may reveal that strains approaching or exceeding the design level are occurring, or are predicted to occur in the future. In these cases the pipeline operator will have to assess if the pipeline is fit for continued service. In principle strain based design approaches could be adapted for such an assessment.

Strain based design approaches place more onerous demands on the linepipe and the girth welds, but for a new pipeline these requirements can be addressed during design, material specification, procurement and weld procedure qualification. However, for an existing pipeline the data required to use strain based approaches may not be readily available. Some strain capacity models are only valid over a restricted range of inputs and so cannot be used in all cases. Hence there is a need to develop guidance for assessing the fitness for purpose of a stress based design pipeline that is found to be experiencing high axial strains.

The European Pipeline Research Group (EPRG) has initiated a program to develop such guidance. This paper presents the results of the first stage of this program. The requirements for data such as inspection records, weld metal fracture toughness and parent pipe mechanical properties are considered. A flow chart has been developed to guide operators when assessing an existing pipeline found to be subject to high strains, and a gap analysis identifies areas where additional work is required.
Condition Assessment for Optimizing Gasunie’s Network Improvement Program (GNIP)
Authors: Hommes Martin , van Bloemendaal Karen , Coster Roelof , Gielisse Maurice , van Agteren Martin H. , Jager Eric E. R.
Published: November 2018

The regional gas transmission network of Gasunie Transport Services in the Netherlands consists of roughly 3000 km pipelines, 3000 valve stations, 75 pressure regulating and metering stations and 1100 gas receiving stations. Because the majority of these stations was built in the period 1960–1980, questions have arisen regarding their remaining technical lifetime and which measures should be taken to comply with future safety and transport standards. In the Gasunie Network Improvement Program (GNIP), these stations are replaced completely, prioritized on their expected condition.

By supplementing the GNIP Verification Project (GVP) to the GNIP, a “Plan-Do-Check-Act” circle was introduced to identify improvements from executing the GNIP. In the GVP, lifetime critical parts of the replaced stations are inspected by specialized companies, in-situ as well as in their laboratories, to assess their actual condition. The lessons learned and results from the GVP have led to adjustments in the replacement program in terms of both scope and pace.

This paper gives a general overview of the GNIP and the GVP. The results of the GVP are then presented with a focus on the condition of gas delivery stations, particularly the condition of components that are not or poorly accessible during normal operation, such as headers and wall crossings. The actions taken by Gasunie to adjust the GNIP based on the GVP outcomes will be discussed.
Terrain Analysis and Geologic Hazards Assessment: A Comparison of the Objectives and Methods of Each, and the Benefits of Completing Both in Parallel
Authors: Theriault Bailey , O’Leary Dennis , West Donald , Nixon Mark
Published: November 2018

Terrain analyses and geologic hazards assessments are recognized as important components for pipeline planning, permitting, and asset management. Although the two types of assessments have inherently different objectives and outputs, there is some overlap in the results between the two and they tend to complement each other; thus, there are benefits to conducting the two assessments in parallel, and integrating the results. Likewise, situations may arise where information from both assessments may simultaneously prove useful in driving decision-making.

Terrain analyses seek to identify homogenous terrain units based on material types, surface expression, depth to bedrock, slope, drainage, and geomorphological processes. Information compiled during a terrain analysis helps to develop a detailed understanding of the local terrain, which can be used to estimate geotechnical soil properties, provide cost savings, and formulate sound decision-making throughout the life of a pipeline.

Geologic hazards assessments generally seek to individually identify, map, characterize, and ultimately allow for mitigation/monitoring of potential geologic hazards, through increasingly detailed geomorphic/geologic assessments. Some typical geologic hazards that are evaluated include landslide, seismic, subsidence, and hydrotechnical hazards. Once identified, a qualitative hazard classification (e.g., low, moderate, high) is generally assigned to each possible hazard, based on several criteria such as the activity level of the geologic process, rate and magnitude of movement of the hazard, the areal extent and proximity of the hazard, the estimated likelihood that the hazard would affect or engage a pipeline during its service life. The hazard classifications are often then tied to recommendations for additional assessment and/or response and mitigation.

The identification of a landslide will be used as an example to highlight how the two assessments can overlap and complement one another, but still provide unique information, and how the two assessments can be used in conjunction to inform better decision-making. Both assessments may identify the location of the same landslide or potentially unstable slope. The geologic hazards assessment would further characterize the landslide’s spatial relationship to the pipe both laterally and vertically, its activity level, etc., in order to evaluate the potential hazard the landslide poses to the pipeline. If mitigation was deemed necessary, information from both the terrain mapping and geologic hazards assessment could be used to evaluate the specific characteristics of the landslide, as well as the surrounding terrain, in order to select the most suitable form of mitigation.
Failure Assessment of the Gas Pipeline by Considering the Geometric Constraint Effect
Authors: Hui Feng , Chunyong Huo , Qiang Chi , Junnan Lv , Qun Li
Published: November 2018

Due to the extensive applications of large diameter/thickness and higher pressure gas transmission pipelines, and there will be an increasing need for reliable pipeline design and failure assessment that will preclude catastrophic accident. Specifically, the actual fracture toughness needs to be determined accurately. The present work innovatively correlate the material’s fracture toughness with the crack-tip geometric constraint effect by using the crack-tip plastic zone. The significant “thickness effect” impact on pipeline steel’s fracture toughness is elucidated by the proposed out-of-plane constraint factor 1αout. The critical loads (FCi) of three groups of thin thickness specimens at fracture are recorded by the three-point bending tests performed on the single-edge notched (SENB) specimens, corresponding fracture toughness are calculated according to the ASTM E1921-97 procedure. Moreover, finite element simulation of the SENB specimens, coupled with the applications of cohesive zone model (CZM), virtual crack closure technique (VCCT), the X70 pipeline steel’s critical energy release rate (ERR) is achieved and applied to predict the FCi of arbitrary specimen thickness while crack initiates, corresponding fracture toughness KCi are obtained and compared with the experimental ones. The present research will be beneficial for the prediction of pipeline steel’s actual fracture toughness and the retrenchment of experimental costs.
Management System Competency Model and Development Program
Authors: Jean Mark S. , Sikorski Lynn A. , Zaleschuk Laura P.
Published: November 2018

The pipeline industry continues to look for ways to improve its compliance and performance. Management systems have increased prevalence in the pipeline industry, with recognition that carefully designed and well-implemented management systems are the fundamental method that should be used to keep people safe, protect the environment and align organizational activities.

Experience has shown significantly better success rates with management system implementation, both in terms of the quality and speed, when the person responsible for the design, implementation and sustainment of the management system has an integrated set of technical and enabling competencies. However, there is currently no standardized competency model that can be used to support a Management Systems Professional’s specialized knowledge and skills. The paper outlines the competencies needed by individuals to be effective in the design, implementation, measurement and evaluation of management systems.

Applying a ‘whole-person’ perspective, the model includes business, relational and technical competencies that contribute to performance excellence for management system practitioners, including outlining example behaviours at target level performance and proficiency, and supported by a defined body of knowledge.

This paper describes the Management System Competency Model, including how it can be used to create a position-specific development program for application within various organizations. This research establishes a basis for the creation of a practical, systematic and easy to use development road map for individuals and organizations who use or leverage a management system.
Safety Culture Assessment and Continuous Monitoring Approach
Authors: Jean Mark S. , Zaleschuk Laura P.
Published: November 2018

Safety culture is not a new concept, with origins dating back to 1986 and the Chernobyl nuclear disaster.[1] The recognition of safety culture in organizations and its influence on incidents has been growing, with gaps in safety culture having been cited as a major contributory factor to recent failures in the oil and gas industry including the Piper Alpha event nearly a quarter of a century ago and was most recently identified as a causal factor in the 2010 Deepwater Horizon disaster.[2]

Many different approaches have been developed to measure and assess organizational attitudes and behaviours, with the goal of improving safety culture. Traditional approaches for measurement have focused on:

▪ Questionnaires or surveys.

▪ Interviews.

▪ Observations.

▪ Focus groups.

▪ Document analysis.

While these approaches have provided valuable information regarding safety culture, more progressive approaches are being considered by leading companies. The establishment of Safety Culture Indicators and Continuous Monitoring as a method for improving safety culture is becoming more prevalent. This new approach enables companies to leverage the management systems that already are in place for managing their increasingly complex operating environments. Regulators have recognized this too and are beginning to recommend that continuous monitoring be included in a company’s toolbox as an additional approach to assessing internal safety culture.

This paper describes a comprehensive safety culture maturity model created to provide organizations with a method to review their management system and assess their existing safety culture. The assessment aids the development of a suite of organization-specific indicators to facilitate application of a continuous monitoring approach for ongoing improvement of safety culture.
A Calculation Model for Leak Detection and Location of Single Pipeline With Two Leaks
Authors: Diao Xu , Jiang Juncheng , Ni Lei , Pan Yong , Chen Qiang
Published: November 2018

Pipeline, as one of the transportation modes, is playing an increasingly important role in national economy. But leakages in pipelines may cause severe problems, such as environmental damages and economic loss. Therefore, how to calculate the leak location and leak size has been investigated for last decades. This paper presents a calculation model based on time-domain analysis solution for detecting and locating two leaks in the pipeline. The model is based on a transient event that is generated by fast closure of the valve at the end of a reservoir-pipeline-valve (RPV) system. The presence of leak causes continuous drops in pressure waves and leak information can be revealed by analyzed the leak transient pressure waves. The time of reflection wave represents the leak location and the magnitude of the piezometric head represents the leak size. The governing equations for calculating the leak size are derived as a system of linear equations based on the Method of Characteristics (MOC). The first transient pressure wave was analyzed to obtain the calculation parameters. Then the applicability of this method is verified on simulated pressure data. The results indicate that this model can perfectly solve two leaks problem in a single pipeline.
Effective Risk Management for In Service Pipelines: Achieving ALARP by Pressure Management and Slab Protection
Authors: Carroll Francis , Hayes Jan
Published: November 2018

In Australia (and the UK), pipeline operating companies have a regulatory obligation to ensure that their assets are designed, constructed, operated and maintained so that risk to people and the environment is as low as reasonably practicable (ALARP). In many routine cases, demonstration that risk is ALARP is a matter of compliance with relevant technical standards. There are some cases, however, that are more complex.

If a pipeline has been subject to significant urban encroachment and does not conform to current design standards for this service, how does a pipeline operator decide whether risk controls are sufficient? In Australia, rather than either ‘grandfathering’ requirements or mandating retrospective compliance with new standards, operators are required to ensure pipelines are safe and that risk levels are acceptable. The answer in cases such as this is a matter of judgment and we have legal, moral and reputational responsibilities to get decisions such as this right. There is currently no formal requirement in the US for pipeline risks to be ALARP, although the concept is gradually being introduced to US industry safety law. Examples include US offshore well control rules, California refinery safety regulations and the nuclear sector concept of ‘as low as reasonably achievable’.

In this paper, we demonstrate application of the ALARP process to a case study pipeline built in the 1960s that has been heavily encroached by urban development. The Australian risk-based approach required formal ALARP assessment including consideration of options to reduce pressure, relocate or replace the pipeline, or increase the level of physical or procedural protection.

Current and predicted operating conditions on this existing pipeline allowed reduction in operating pressure in some of the encroached segments, sufficient to achieve the equivalent of current Australian requirements for ‘No Rupture’ in high consequence areas for new pipelines. In other areas this was not achievable and a lesser degree of pressure reduction was instigated, in combination with physical barrier protection. The physical barrier slabbing comprised over 7 km of 20 mm thick high-density polyethylene (HDPE) slabs, buried above the pipeline. This approach was new in Australia and required field trials to confirm effectiveness against tiger tooth excavators and rotary augers.

These upgrades to the case study pipeline have significantly decreased the risk of pipeline failure, by reducing both likelihood and consequences of accidental impact. In combination with rigorous procedural controls such as patrol surveillance and community liaison, real risk reduction has been achieved and ALARP has been demonstrated.
Robust Nanocomposite Coatings Inspired by Structures of Nacre
Authors: Kockerbeck Zachary , TabkhPaz Majid , Park Simon , Hugo Ron
Published: November 2018

Carbon steel piping can be exposed to environments that contain various chemical and organic elements that induce corrosion and cracking events. This can lead to the loss of fluid into surrounding sensitive and remote environments. To minimize this inherent risk, various coating technologies have been utilized over the years in industry. These coatings typically suffer from complex application methods, high application cost, and vulnerabilities to environmental effects such as mechanical damage and cathodic disbondment. To overcome these challenges, a novel epoxy based composite coating that utilizes the properties of various nano-particulates such as graphene nanoplatelets (GnP), multi-walled carbon nanotubes (MWCNTs), chitosan, and hBN (Hexagonal boron nitride) is developed. These nanoparticles create a nano-scale “brick and mortar” type effect that is analogous to various natural structures such as the abalone shell (nacre). These nano-structures also enhance coating performance by increasing mechanical strength and anti-bacterial properties while simultaneously decreasing gas permeability. This performance enhancement serves to reduce overall corrosion-induced disbondment area. The dispersion of nanoparticles is verified using various microscopy methods such as scanning election microscopy and an optical 3D profilometer. To confirm the role of nanoparticles in the epoxy composite, the samples undergo rigorous testing to determine both mechanical properties as well as the feasibility of coating application, in particular, for use on girth welds. Using a dynamic mechanical analysis (DMA), the material strength of each combination of nanocomposites is tested and used to determine the glass transition temperature. The testing also includes abrasion, and both long-term mechanical and thermal behaviors of the coating. To test the feasibility of the coating, cathodic protection tests in an accelerated corrosive environment, and gas permeability tests are carried out. The results show that the composite coating made from these nanomaterials had a decrease in cathodic disbondment area and gas permeability and an increase the glass transition temperature and scratch resistance. Therefore, the nanocomposite coatings are found to be a significant improvement over standard epoxy-based coating.
Investigation on Drag Reduction Through Dimple Machining
Authors: TabkhPaz Majid , Howell Lindsay , Kockerbeck Zachary , Park Simon , Hugo Ron
Published: November 2018

High friction between a fluid and a pipe wall results in increased pumping requirements. This friction contributes to lower production rates and reduced system capacity. Thermal heating, fluid blending, and drag reducing agents (DRA) are commonly used methods for decreasing pressure drop in pipelines. Surface patterns inscribed onto internal pipe walls have also been shown to reduce fluid friction.

In this paper, the effects of different surface patterns on the shear between a fluid and a wall are studied. Surfaces with different dimple patterns are investigated. Micro-dimpled patterns on the surface are created using an inclined, flat end micro-milling tool. The surfaces with different dimpled patterns are characterized and tested through morphological, contact angle, and viscosity measurement studies. The effects of the surface patterns are also studied through simulation. A Power Law relationship and apparent fluid viscosity is determined for the low Reynolds numbers investigated. The deepest dimpled surfaces investigated (0.2 mm dimple depth) result in a drag reduction of approximately 20% for silicone oil. Further research and application of the results to transmission pipeline systems are discussed.
Development and Execution of Consequence Assessment for Liquid Pipeline Facilities
Authors: Ferdous C. M. Refaul , Beaudin Chris , Payoe Anthony , Li Lily
Published: November 2018

Risk assessment is an effective and commonly practiced process in industry, including oil and gas sector, as a basis for designing new pipeline terminals and stations and managing integrity of existing facilities. A holistic risk assessment method, which could be qualitative or quantitative, includes both the likelihood and consequence assessments of an undesired event. Prior to 2015, Enbridge Pipelines employed a qualitative risk assessment algorithm to assess the likelihood and consequence of a failure of liquids pipeline facilities.

Over the past decade Enbridge has identified a number of shortcomings with the qualitative approach, necessitating the development and use of Quantitative Risk Assessment (QRA) to support consistency and defensibility in risk-informed decision making. A QRA requires rigorous quantitative algorithms to measure public and environmental safety, and potential business consequences of an undesired event at a facility. While significant literature has been produced, and considerable effort has been expended to quantify the potential impacts of a flammable product release on public safety, very limited work has been done on the quantitative measurement of environment related impacts. In particular, limited research has been successful in aggregating environmental consequences, public safety and business consequences to estimate the total consequence of a liquid hydrocarbon release within a pipeline facility.

The consequence assessment of an unwanted event conducted through QRA can be combined with the associated likelihood to provide a quantitative measure of risk. This risk level may be used to support organizations in making risk informed decisions and in analyzing and treating facility risks, specifically in the:

• Identification of top risk facilities and high consequence functional areas;

• Identification of assets posing the most risk and worst case consequences;

• Understanding of system reliability risk and opportunities to optimize facility operation;

• Prioritization of facility maintenance projects in the capital and operating budget processes;

• Supporting regulatory requirements and expectations;

• Presentation of risk down to the equipment or component level; and

• Understanding of residual risk and achieved risk reduction.

This paper describes the development of a consequence model that monetizes the quantitative measure of public and environment safety, and potential business losses for a liquid product release at pipeline facilities. The proposed model characterizes the severity of impact of released product, expressed in dollars per event, as a function of system volume, proximity and category of receptors, asset location, and available controls.
Adaptive Ultrasonic Imaging of Electric Resistance Welded Pipeline Seams
Authors: Haines Harvey , Hörchens Lars , Schouten Jasper
Published: November 2018

Imaging techniques using full matrix capture (FMC) ultrasonic NDE are well suited for in-service examination of electric resistance welded (ERW) pipe seams. We have been involved in developing an imagine technique since 2013 and presented results from Phase I at IPC in 2016 showing the system capable of detecting seam weld and SCC flaws and determining their orientation. The advantages over other methods such as phased array (PA) is the ability to image the flaw surface in addition to the flaw tip and corners where the flaw intersects the pipeline surface. This improves the ability to determine flaw orientation for discrimination of different types or crack-like features. The system produces UT images by overlaying multiple modes using reflections off the ID and OD pipe surface for ultrasonic illumination of the weld area from different directions. Using multiple modes produces a reflection off features regardless of flaw orientation from at least one of the modes. A complementary mode can then be used to size each feature by detecting the tips or ends of the feature from lower amplitude diffraction signals. Phase I used a model which assumed a cylindrical pipe shape. Real world use of this technique found limitations when pipe deviated from the assumed cylindrical shape such as severe offset plate edges, flat spots which can be the result of poor crimping adjacent the seam weld, or thickening of the seam caused by post weld heat treatment.

In Phase II a need for reduced sizing error led to improved calibration and more advanced processing. To compensate for the non-perfect nature of real pipe, a new adaptive IWEX technique was developed to improve focusing and alignment of the various modes using the actual geometry to construct better focusing laws. First the OD and ID surfaces are imaged and the resulting surfaces are used to construct focusing laws which adapt to changes in the OD and ID surfaces. Results are better aligned UT images with the ability to image complex flaws with changes in orientation, and the ability to discriminate complex flaws from multiple small flaws in the pipe. Results show improvements in pipe with the greatest improvements in pipe with the largest deviations from a cylindrical shape.
Utilizing Value Management to Increase Project Competitiveness
Authors: Tozer Michael , Tetteh-Wayoe Debra
Published: November 2018

With the current economic pressures being faced by the oil and gas sector, organizations are increasingly required to become more competitive on their capital projects. Enbridge has implemented the practice of Value Management (VM) to help achieve the needs and expectations of stakeholders with the least possible resources.

VM is a systematic approach that is used by a multidisciplinary team to improve the value of a project (or aspects of a project) through the analysis of its functions, and is most effective when applied at the planning and development stages. A value study enables the expected performance (i.e. the desired functions) of a project to be clearly identified at the onset, and assesses a range of possible solutions/alternatives against the functions required by the owner.

While VM is commonly used in the manufacturing industry, as well as on transportation and municipal projects, few examples of its application in the oil and gas sector were found. Enbridge researched a variety of VM best practices and created a framework that compliments existing company practices.

This paper also highlights how the value methodology was recently applied to a capacity expansion project at the Front End Engineering and Design (FEED) stage. Our approach to the various elements of a value study will be discussed, including pre-workshop activities, the VM workshop, and post-workshop activities.

Enbridge has seen significant benefits from the VM studies completed on projects to-date. Given the broad applicability of the value methodology, it is believed that our approach can also be successfully applied in other areas (e.g. improving business processes).
A More Accurate and Precise Method for Large Metal Loss Corrosion Assessment
Authors: Zhang Shenwei , Yan Jason , Kariyawasam Shahani , Huang Terry , Al-Amin Mohammad
Published: November 2018

Pipeline integrity decisions are highly sensitive to the assessment model. A less accurate and less precise model can conservatively trigger many unnecessary actions such as excavations without providing additional safety. Therefore, a more accurate and precise model will reduce excavations and provide higher assurance of safety. This is akin to using a more precise surgical tool such as a laser for cutting out a brain tumor where you can cut closer to the edge and be assured of cutting out more of the tumor (safer) and yet cut less of the surrounding brain tissue (less conservative).

This paper presents a novel model for assessing large metal-loss corrosion based on in-line inspection (ILI) or field measurement. The model described in this paper utilized an unconventional approach, namely multiple plausible profiles (P2), to idealize the shape of the corrosion, and therefore is referred to as P2 model. In contrast, all existing models use one single profile for characterizing corrosion profile, e.g. RSTRENG utilizes a single worst-case river bottom profile to characterize the shape of corrosion.

The P2 model has been initially validated using fourteen (14) full scale specimen-based hydrostatic tests on pipes containing real large corrosion features. Validation results showed that the P2 model is safe, but less conservative and more precise than RSTRENG. The magnitude of reduction in conservatism depends on the corrosion morphology. On average, the P2 model achieves 15% reduction in model bias and 44% reduction in standard deviation of model error. Further validation was provided using the testing data published by PRCI and PETROBRAS. Another set of burst tests are being conducted by TransCanada as part of the continuous validation of P2 model.

The effectiveness of the P2 model was demonstrated through two case studies (denoted by Case study 1 and 2). Case Study 1 included 170 external metal-loss corrosion features that were excavated from different pipeline sections, and have field-measurements using laser scan tool. Case Study 2 included 154 ILI-reported external metal-loss corrosion features with RSTRENG calculated rupture-pressure-ratio (RPR) of less than or equal to 1.25 (i.e. RPR ≤ 1.25); hence, these features were classified as immediate features. The Case Studies showed that the use of the P2 model resulted in 80% less number of ILI-reported features requiring immediate action (i.e., RPR ≤ 1.25) and 89% less number of excavated features requiring repair (e.g., sleeve or cut-out) compared to the respective number of features identified by RSTRENG-based assessment. The reduction in the number of features requiring excavation or repair is highly morphology-dependent with the highest reduction achievable for pipeline containing long and wide corrosion clusters (e.g., tape-coated pipeline). However, the P2 model is applicable to all clusters regardless of the number of individual corrosion anomalies associated with the cluster.
Validating a Single-Phase Flow Pipeline Simulation Model Against Real Data From a Vapor Collapse Event
Authors: Pietsch Ulli , Sieben Hanna
Published: November 2018

Transient hydraulic conditions during a shutdown and subsequent start-up of a segment of a pipeline that runs through a mountainous region were simulated using commercially available hydraulic simulation software and a model of the relevant portion of the pipeline facilities. The segment of interest is located in an area where the pipeline is normally operated with vapor present (slack line flow conditions) due to the large change in elevation. Pressure data that was recorded by the pipeline’s data acquisition system indicated a pressure surge occurred when the line was restarted. The suspected cause of this pressure surge was the collapse of the vapor in this pipeline segment. Beginning with an estimate of the flow, pressure and temperature data for the pipeline segment at steady state conditions prior to the shutdown, the simulation was tuned to reasonably match the measured data. The resulting simulated data closely replicated the surge event. Examination of the simulated data provides insights into the hydraulic conditions in the pipeline at locations where pressure data is not measured, as well as during the time intervals between data acquisition scans. It also reveals impact of the timing of the mainline valve opening sequence. Further, since the simulated data does accurately replicate the actual measured data, the model can be used to evaluate how changes to facilities or operating conditions impact the formation and the collapse of vapor in this pipeline segment.
Effect of Model Error on Reliability Analysis of Surface Cracks
Authors: Ibrahim Mahmoud , Doucette Karmun , Hassanien Sherif , Langer Doug
Published: November 2018

The application of reliability-based structural integrity enables the process of quantitative risk assessment as part of pipelines’ integrity management program (IMP). This paper explores two topics that present challenges in terms of the practical adoption of a reliability-based IMP. The first challenge is the balance between perceived and true risk when implementing a quantitative reliability-based integrity model. This is a cornerstone for building stakeholder confidence in the calculated probability of failure (PoF) which is applied to safety and economically driven integrity decisions. The second challenge is the assurance that all relevant sources of uncertainty have been incorporated, which is essential for ensuring an accurate representation of the risk of failure of the pipeline. The level of conservatism (i.e. sufficient margin of error to maintain safety) incorporated when addressing these challenges may create a situation where calculated PoFs become inflated; becoming disproportionate to the failure history and contradictory to the current safe operation of pipelines being modeled. Two different PoF calibration approaches are proposed as practical options to address these challenges. The first method calibrates model error using an operator’s in-service failure history (i.e. failures that occurred under normal operation). The second method uses a set of failure data (including hydrostatic test failures and in-service failures) as selected by the operator considering key factors to ensure adequate representation of their specific pipeline system. These options will be demonstrated by assessing the integrity reliability of a hypothetical pipeline system. This work is expected to help evaluate the feasibility of challenging current practices regarding practical inclusion of epistemic uncertainty in integrity reliability analysis of pipelines.
An Authoritative Comparison of Remaining Life Assessments for Pipeline Dents
Authors: Dotson Rhett , Holliday Chris , Torres Luis , Hagan Damien
Published: November 2018

A significant amount of effort has been expended in the area of advancing pipeline dent remaining life assessment methods beginning in the late 1980s and extending to the current day. Initial research efforts were primarily empirical in nature while more recent research efforts have incorporated finite element modelling. Coupled with advancements in assessment techniques, the capabilities of advanced in-line inspection (ILI) tools have increased to a point where they can provide consistent, reliable information that is suitable for dent assessments. As a result of these advancements in assessment models and ILI tools, operators can now perform remaining life assessments using ILI data, and a multitude of remaining life assessment models are available, including solutions from the European Pipeline Research Group (EPRG), Pipeline Research Council International (PRCI), American Petroleum Institute (API), and finite-element based approaches. In addition to these remaining life assessments, many operators routinely perform strain-based assessments based on guidance from ASME B31.8. To date, there have been few studies comparing the various assessment methods on large numbers of dents, and as a result, significant questions persist as to the conservatism inherent in each method. In addition, the EPRG and PRCI methods are largely based on full-scale testing and finite-element models performed with idealized indenter shapes while actual pipeline dents typically exhibit complex shapes and interactions between multiple dents. Each model also has limitations and advantages that are discussed in this paper, such as ease of use and how pipeline geometry and weld association are considered. This paper provides a robust comparison of selected dent assessment methodologies on 220 actual dents from a 24-inch pipeline with depths ranging from 0.6–4.5% OD, and 32 dents from a 30-inch line with depths ranging from 1–2.5% OD. The assessment includes both top and bottom of line dents and investigates the influence of restraint on remaining life. The results presented in the paper are based on high-resolution ILI caliper data collected during two in-line inspections. Furthermore, the paper provides statistical comparisons between strain and remaining life methodologies and also between the various remaining life assessments. The paper also provides a comparison of the restraint parameter from the PRCI model with calculated stress concentration factors from finite-element models. The paper provides a first of its kind comparison of the various methods and discusses how the work may be extended to other pipe diameters and wall thicknesses.
Validate Crack Assessment Models With In-Service and Hydrotest Failures
Authors: Yan Jason , Zhang Shenwei , Kariyawasam Shahani , Pino Maria , Liu Taojun
Published: November 2018

Crack or crack-like anomaly is one of the major threats to the safety and structural integrity of oil and gas pipelines. Various assessment models have been developed and used within pipeline industry to predict the burst capacity for pipelines containing longitudinally-oriented surface cracks. These models have different level of conservatism, accuracy, and precision which significantly impacts pipeline operators’ integrity mitigation decisions such as pressure restriction, excavation, and repair, and also lead to different level of safety.

This paper compares the accuracy and precision of the most commonly used crack assessment models, i.e. Modified Ln-Sec, CorLAS, API 579 Level 2 and the recent-published PRCI MAT-8 model using in-service and hydrostatic testing failure data. A total number of 12 in-service and 63 hydrostatic test pipe ruptures due to stress corrosion cracking (SCC) with actual burst pressure, material property, and detailed crack size measurements are collected, and used to derive the probabilistic characteristics of the model errors associated with each model. Compared to the burst tests conducted in the laboratory and investigated in other previous studies, the results obtained from in-service and hydrostatic test ruptures are more representative of the real boundary conditions in pipeline operation. All the assumptions and empirical correlations associated with each model are discussed in details. The analysis result suggests that CorLAS is the most accurate model with the least uncertainty (or highest precision). Mitigation activities can be optimized without compromising safety by using the most accurate and precise model.
Quantitative Risk Assessment Techniques Based on Uncertainty Theory for Natural Gas Distribution Station
Authors: Zhou Jiao , Peng Xingyu , Yao Dongchi
Published: November 2018

Pipeline stations, as an important part of long-distance pipeline systems, include lots of facilities which are highly concentrated and always operate continuously. Risk assessment is an important foundation work for the risk management of these stations. Since various uncertainties exist during the quantitative risk assessment (QRA), this paper explores the theories and approaches of QRA for station accidents, and also introduces some specific mathematical theories for quantification and dealing with uncertainties. This paper combines uncertainty theory effectively with the QRA for gas distribution stations, analyzes the uncertain factors in the QRA of gas distribution station, and establishes Bayesian update model for estimating basic events’ failure rates and probabilities of failure on demand based on generic failure data and plant-specific data. And it also offers conversion method among conjugate prior distribution of different types. Besides, probabilistic estimation model is set up by the combination of fuzzy set theory, expert judgments and fuzzy group decision making. The paper builds Fuzzy Bow-Tie quantitative model for distribution station under dependency relationships, and proposes the sensitivity analysis method for the accident model based on fuzzy importance index, fuzzy uncertainty index and minimal cut sets importance index.