bluuebunny/crossref_metadata_2025 huggingface dataset:
Use of High Density Polyethylene (HDPE) Slabs As an Effective Risk Mitigation Method for Mechanical Damage Hazard
Authors: Al-Amin Mohammad , Law Jonathan , Choudhary Usman , Bolaños Carla
Published: December 2024

This paper presents the development history of high density polyethylene (HDPE) slabs as a mechanical protection barrier including all field and lab testing performed by various organizations to determine the effectiveness of HDPE slabs. All available test results for HDPE slabs were analyzed and compared with the test results for concrete slabs to determine the effectiveness of HDPE slabs in reducing pipeline hit compared to concrete slabs. The findings from the comparative study are presented in this paper. This paper describes the learnings and success story of TC Energy’s implementation of HDPE slabs as a mechanical protection method. The benefits of HDPE slabs compared to the traditional concrete slabs in TC Energy’s implementation are also presented in this paper.
Effective Analysis of Liquid Pipeline System Performance Post Upgrade Project
Authors: Ma Te , Mansour Vivianne , Qiao Sean
Published: December 2024

It is difficult to analyze the performance of liquid transmission pipelines that transport products through a process called batching which allows multiple products, such as heavy crude oil, refined and semi-refined products to be transported in batches one after another. This is because the products delivered vary in batch content, batch size and batch position. A combination of operating data analysis and Hydraulic Pipeline Simulator modeling could be used to effectively analyze the pipeline system performance improvements following a pipeline system upgrade to justify the project’s economic benefits.

The subject pipeline is a liquid transmission pipeline with approximately 1,150 km total length of pipe (nominal diameters of 610 mm / 762 mm / 914 mm) and twenty-three (23) pump stations. The pipeline delivers approximately 300,000 bbl/day of diverse types of crude products ranging from refined petroleum to heavy crude. In addition, the delivery batch line-ups vary from day to day. A system upgrade project was completed to improve the system throughput. The upgrade included installing larger motors and Variable Frequency Drive (VFD) at 7 of the 23 pump stations. Following the system upgrade, a method for quantifying post-project benefits was derived for a pipeline system using batch delivery to determine the pipeline throughput improvement and pump power consumption saving.

This paper showcases the analytical considerations and calculation methodologies involving pipeline operating SCADA (Supervisory Control and Data Acquisition) data analysis and Hydraulic Pipeline Simulator modeling as a combined approach. Both analytical approaches are utilized to evaluate the performance improvement of the subject pipeline system upgrade in terms of system throughput and power saving. It was concluded that the pipeline system throughput was improved up to 5% and annual energy savings of 18% was achieved post system upgrade.

With the optimized analytical evaluation method, the pipeline system performance improvement was effectively evaluated to demonstrate the economic benefits of such a system upgrade project. This combined analytical approach can be used for future system upgrade project discovery guidelines.
Going Beyond ASME B31.12: A Technical Feasibility Case Study for the Conversion of a 16” X 20 km Onshore Gas Pipeline to Hydrogen Storage
Authors: Sandana Daniel , Hopkin Sarah , Martin Tom , Gallon Neil , Doyle Jonathon , Guijt Wim , Timmerman Robert , Baby Benjose
Published: December 2024

The conversion of existing assets to hydrogen needs to be managed with due diligence. Current industry codes such as ASME B31.12 have remained relatively immature in their approach to repurposing and do not yet reflect the rapidly evolving research developments in this areas, for example accounting for the presence of historic defects and damages. This paper proposes a method for pragmatic and safe pipeline repurposing that presents the project with an early screening of major barriers that may potentially compromise repurposing. In line with current industry knowledge, this approach includes the removal of conservatisms associated with some of the design equations given in existing codes i.e. ASME B31.12.

The case study provided to illustrate this process is a 20 km 16″ pipeline proposed for conversion to hydrogen storage. The overall objective was to define a safe operating envelope within which the capacity of all segments of the vintage pipeline can be maximized. The input data, assumptions made where data was unavailable or incomplete, engineering critical assessment methods and defect compliance criteria, and results are provided. The operating envelope is tested against potential H2 operating cases, and a test and inspection plan proposed to confirm the assumptions made as future work. Conservative decisions in light of open industry gaps are highlighted where applicable.

The study provides a clear, documented demonstration of feasibility for hydrogen storage within a specified operating envelope of restricted pressure and pressure cycling before further committing to subsequent repurposing strategy phases.
Development and Implementation of a Dent Engineering Critical Assessment (ECA) in Accordance with PHMSA’s Gas Mega Rule
Authors: Tang Huang , Kohlenberg Derek , Sun Jialin , Zheng Guanbo , Oviedo Fernando , Di Blasi Martin
Published: December 2024

In the 2019 US Gas Transmission Rule referred to as the “Mega Rule”, PHMSA introduced a new section within CFR 192.712 [1], allowing operators the opportunity to develop procedures and perform Engineering Critical Assessment (ECA) leveraging industry standards such as API RP 1183, ASME B31.8S [2, 3], or other current research findings to determine if dents and mechanical damage anomalies should be responded or monitored beyond the prescriptive requirements referenced in CFR 192.714 and CFR 192.933. In addition, PHMSA provided guidelines to operators on what an acceptable ECA procedure should consider. If an operator chooses to perform an ECA process, submission of advanced notification with the relevant procedures in accordance with CFR 192.18 would be required.

For operators to assess a prevalent pipe integrity threat such as dents, industry standards refer to multiple levels of assessment methods, with increasing orders of complexity and decreasing levels of conservatism. The purpose of this paper is to provide technical suggestions on the development and implementation of an ECA workflow to assess dents and to determine their fitness for service. This paper provides suggestions on how to address plain dents with strain levels potentially exceeding 10% strain limit which typically can account for a significant portion of the dents identified through ILI. The paper also describes the FAD-based method to conduct fracture assessment on cracks/gouges coincident with dents. A workflow was also developed to conduct fatigue crack growth assessment on dents interacting with cracks/gouges in accordance the CFR Mega Rule requirements.

Finally, a software tool has been developed to automate the dent ECA process. With this automation, the efficiency in conducting dent ECA could be significantly improved ensuring that a prompt action will be taken on potentially injurious dents. A case study on hypothetical dents was conducted demonstrating the robustness of the workflow performed with the automation tool.
Real-Time Detection of Solid and Liquid Contaminants in Natural Gas Streams Using Microwave Sensing Technology
Authors: Chan Nicholas , Botros Kamal K. , Saif Ur Rahman Mohammed , Abou-Khousa Mohamed , Alshehhi Mohamed , Al-Wahedi Khaled , Leong Keith
Published: December 2024

The production and transportation of high-quality natural gas, that is free of liquid/solid contaminants, is critical to fulfilling the increasing global demand of this commodity. Despite several mitigation strategies from natural gas producers and distributors, liquid and solid contaminants are still commonly found within natural gas pipelines. As such, a need exists for real-time detection of these contaminants, within natural gas pipelines, in order to determine contaminant sources and reduce contaminant quantities. In this study, an in-line, non-perturbing, real-time, microwave-based contaminants sensing technology was developed and tested at a natural gas test facility located in Alberta, Canada. The contaminants detector was installed on DN150 pipe and tested over a gas velocity range of 1.3–13.2 m/s. First, glass oxide particles were intermittently injected into the gas stream immediately upstream of the detector. Two different glass oxide particles were tested with particle diameter ranges of 44–88 μm and 88–149μm. Second, liquid contaminant, in the form of compressor lubrication oil, was atomized into the gas stream immediately upstream of the detector. Three types of atomizing nozzles were used in conjunction with liquid injection pumps to test liquid injection rates in the range of 0.07–0.7 L/min. Liquid and solid contaminants were successfully detected using the standard deviation of in-phase and quadrature baseband voltage measurements from the contaminants detector. This paper quantitatively evaluates the solid/liquid contaminants detection performance of this detector in the context of natural gas pipeline applications.
Off-Property Release Likelihood Assessment of Liquid Pipeline Stations Through Barrier Analysis
Authors: Wideman Jeffrey , Sen Millan , Dombroski John , McKechnie Doug
Published: December 2024

Site containment is installed within pipeline stations as a protection barrier that prevents releases from traveling beyond the station boundary. However, with time barriers may degrade, for example berms may wear down due to vehicle traffic, containment valves may fail to close after decades of use, and/or facility patrol intervals may change. Correspondingly, there is potential that offsite release likelihoods may exceed company targets, which is especially pertinent for stations located in high consequence areas. Therefore, a methodology for evaluating the risk of an off-property release at facilities has been developed. This methodology quantifies both asset likelihood of failures, and the effectiveness of leak containment barriers inconsideration of operations (eg. drainage valve opening) and time dependent deterioration (eg. containment berm degradation).

Review of facility drawings was conducted to inventory the station assets and catalogue the station barriers installed during construction. Field visits were then conducted to acquire information on leak barrier condition, berm and containment pond draining frequency due to precipitation events, and flow paths within the facility should a release occur. Subsequently, fault tree analysis was applied to determine the likelihood of off-property release.

Asset specific probability of failures were used to quantify the basic events. Additionally, output gates determined the likelihood of off-property release via AND gates for redundant barriers and OR gates for dependent barriers. The likelihood of off-property release was quantified for each of the overland, spray, and below ground release modes. Environmental consequence was combined with this likelihood, to enable risk assessment.

The methodology has been applied to multiple pipeline operator stations, and mitigations have been executed based on the results. This demonstrates that application of this methodology may identify whether off property release risk and reliability targets are exceeded, enabling informing of decision makers on mitigation priorities.
An Operators Experience in Developing a Technical Strategy for Repurposing the UK National Transmission System (NTS) to Transport Hydrogen
Authors: Senior Gary , Johnstone Steven , Haswell Jane , Jones Corinna
Published: December 2024

National Gas Transmission (NGT) own and operate the 7660 km National Transmission System (NTS) in the United Kingdom (UK) and have a responsibility to develop the green energy system for the future, while delivering the natural gas needs of today.

There is worldwide interest in repurposing existing pipeline transmission systems from transporting methane to hydrogen. Extensive research is being conducted to understand the implications that hydrogen may have on design, materials, integrity and the resulting safety considerations.

The effective application of the developing research requires a robust technical strategy for repurposing that is underpinned by comprehensive technical procedures which address: the data requirements, the technical assessments to be performed and their reporting requirements.

This paper will describe:

- How NGT via Project Union will facilitate an efficient route to net zero and a hydrogen economy by repurposing existing high pressure natural gas pipelines in the NTS to create a hydrogen ‘backbone’.

- The challenges resulting from hydrogen operation.

- The design and construction basis of the UK NTS and how this understanding is being utilized to develop a hydrogen repurposing methodology.

- The Code challenges in hydrogen repurposing.

- A previous ‘change of use’ UK project and its relevance to hydrogen repurposing.

- An outline methodology for hydrogen repurposing of UK pipelines and installations, which takes due cognisance of the hydrogen challenges, Code requirements and the good practice that has previously been experienced in UK ‘change of use’ projects.

- The opportunity for digital transformation when developing and applying a repurposing methodology.

- The ongoing stakeholder challenges for regulators, code bodies, pipeline operators and service providers.
Development and Implementation of Risk-Informed Decision-Making Framework to Manage Corrosion Threat in Gas Transmission Pipelines
Authors: Kohlenberg Derek , Oviedo Fernando , Di Blasi Martin , Hubert Yvan , Yap Keng
Published: December 2024

Quantitative Risk Assessment (QRA) is becoming an increasingly important part of asset integrity management in the pipeline industry, particularly for assets that can be internally inspected using magnetic flux leakage (MFL) in-line inspection (ILI) tools. The application of QRA to corrosion management involves performing probabilistic risk analysis using structural reliability methods which leverage ILI results, corrosion growth rates (CGR), and relevant sources of uncertainties to calculate the probability of failure (POF) and consequence of failure (COF). The risk quantified in terms of POF and COF, and then assessed against a quantitative reliability framework for each corrosion anomaly.

One challenge arises when trying to make integrity decisions considering both the required prescriptive anomaly response criteria with the risk evaluated through QRA. It is common practice for operators to perform an annual QRA for an entire pipeline network, where anomalies found to be of higher risk are selected for risk-informed planning activities as part of the continuous improvement of integrity core process. This can usually happen after the prescriptive responses have been determined and, in many cases, the resulting repair programs have been started. This timeline disconnect in processes has the potential to lead to dig program inefficiencies and missing the opportunity to reduce even further the level of risk in a resource effective way. When compared to the Pipeline and Hazardous Materials Safety Administration (PHMSA) incident data [14] for natural gas pipeline operators, corrosion is the second most pervasive threat behind Third-Party Damage. This shows how industry-wide incorporation of QRA is becoming progressively more important for operators to optimize their risk-informed decision-making with respect to corrosion management.

The purpose of this paper is to provide technical guidance on how to implement an integrated risk-informed decision-making (IRIDM) framework when combining QRA with prescriptive response criteria referenced in the Code of Federal Regulations (CFR) Title 49, Part 192 and the Canadian Standards Association (CSA) Z662:23 to enhance the safety and efficiency of a corrosion management program. The paper will then establish how the proposed integrated risk-informed decision-making framework performs when applied to a hypothetical population of corrosion anomalies on a North American natural gas pipeline network.
Improvements to B31.8 Dent Strain Estimation and Assessment of Dent Formation Induced Cracking
Authors: Tang Huang , Zheng Guanbo , Sun Jialin , Kohlenberg Derek , Di Blasi Martin
Published: December 2024

Local plastic deformation associated with the dent formation can potentially cause ductile damage leading to cracks. Plastic strain is considered as a key indicator to dent formation-induced cracking. The estimation of local plastic strain in a dent is mainly based on the calculation of dent profile curvatures. The ASME B31.8 effective strain equations [1] provide a basis to convert the geometric curvatures into strains.

In this paper, a variety of methods used to estimate dent profile curvatures were evaluated for calculating the effective strain. Hypothetical dent profiles generated from FEA simulations were used for the evaluation. The effective strains obtained by using the B31.8 equations were compared with the FEA results on equivalent plastic strains for all the simulated dent profiles. It was shown that the estimation of plastic strain was sensitive to the methods used for extracting the dent profile curvatures. A method based on the 4th order polynomial curve fitting on a total of 9 points selected near the dent apex was shown to provide more consistent results compared with other methods investigated in the present paper.

Unconstrained dents pose a particular challenge when using the B31.8 effective strain equations to estimate the plastic strain. The measured dent profiles from pipeline inline inspection (ILI) for an unconstrained dent can be significantly different from the indentation dent profiles due to plastic re-rounding. The estimated plastic strains based on the current dent profile after re-rounding with the B31.8 equation display a significant scatter compared with the FEA simulation results. A regression model was developed to improve the strain estimates based on the B31.8 equations using the current dent profiles after re-rounding. The regression model was intended to compensate for the re-rounding and correct the strain estimates from the B31.8 equations by including the current dent geometries and pipe internal pressure. Trained with FEA simulation results for unconstrained dents, the regression equation was shown to significantly improve the strain estimates compared with the FEA results.
A Decision-Making Method for Scheduling of Branched Multiproduct Pipeline Systems Considering User Satisfaction
Authors: Xu Bin , Li Zhengbing , Tu Renfu , Liao Qi , Liang Yongtu
Published: December 2024

In the context of fairness and openness, multiproduct pipeline systems face significant challenges due to the complex market dynamics. There is an urgent need to enhance scheduling technology to improve the system’s service capacity and operational efficiency. In recent years, the scheduling of multiproduct pipelines has been studied extensively. However, most of previous work has focused on meeting the relatively static demands of fixed users, while seldom taking into account the increased demand for more flexible oil receipt times resulting from the addition of users in a fair and open market environment. Therefore, this paper proposes a decision-making method for scheduling of branched multiproduct pipeline systems considering user satisfaction. Firstly, the topological characteristics and the factors influencing user satisfaction of branched pipeline system are analyzed. Then a mixed integer linear programming (MILP) model is established based on continuous-time representation, the model aims to minimizing the penalty cost due to unsatisfied user requirements, and considers the constraints such as batch tracking, contamination control, refinery upload, oil depot download and transfer of junction to obtain a detailed schedule that meets the actual operational requirements of the system. Finally, the proposed method is applied to a real-world pipeline of China. The results demonstrate that the method can generate a schedule that meets the time requirements of multiple users to receive products, which contributes to increased user satisfaction and enhancing the fair and open service level of the system. This provides valuable technical support for the construction of fair and open pipeline systems.
Mechanistic Insight on Intergranular Near-Neutral pH SCC Using Advanced Microscopy
Authors: Long Fei , Zhang Ken , Persaud Suraj , Daymond Mark R.
Published: December 2024

Stress corrosion cracking (SCC) is a major pipeline degradation mode that often leads to leak or rupture during operation or hydrotest. Near neutral pH SCC was initially discovered to form beneath polyethylene-tape coatings in Alberta, Canada in the 1980s followed by reports from American operators. Unlike the well-studied high-pH SCC that is typically intergranular, previous metallurgical examination in laboratory studies suggest that near-neutral pH SCC is predominately wider and transgranular. The crack walls are often corroded heavily which makes studying the crack propagation mechanism challenging.

In this work, advanced electron-microscopy techniques are applied to study the microstructural characteristics of near-neutral pH SCC in ex-service pipeline material. Firstly, 3D tomography of a SCC was carried out on a plasma FIB (focused ion beam), which revealed the development of cracks with a complex network structure from the external surface. Second, careful examination through scanning electron microscopy (SEM) revealed areas containing fine un-corroded cracks along the main path of the heavily corroded crack. To further reveal the characteristics of the fine cracks, through thickness trenches were made by FIB at the areas where un-corroded cracks were observed. The subsequent 2D imaging revealed that the cracks developed along grain boundaries, as opposed to what conventionally is believed i.e., that near-neutral pH SCC develops transgranularly. Lastly, TEM (transmission electron-microscopy) characterization was carried out on FIB lift-outs from the fine un-corroded cracks. Through electron diffraction, the intergranular nature of the fine cracks was determined. The local plasticity was also quantified by comparing the dislocation densities in the grains where fine cracks developed, to the overall dislocation densities in the pipeline. It is shown that no significant plasticity was involved with the development of fine cracks. Lastly, high resolution EDX (energy dispersive x-ray spectroscopy) revealed only oxidation occurred along the walls of the fine cracks, and no distinct foreign elements existed in the developing crack.

The microstructural study revealed that the examined SCC did not require high stress intensity at the crack tip to propagate, which is in-line with the stress analysis based on operational history and bending strain measurement at the locations. Alternative crack propagation mechanisms will be hypothesized and confirmed by in-lab simulated studies.
Influence of Hardness on Hydrogen-Assisted Fracture in Pipeline Steels
Authors: Ronevich Joseph , Agnani Milan , Gagliano Michael , Parker Jonathan , San Marchi Chris
Published: December 2024

To decarbonize the energy sector, there are international efforts to displace carbon-based fuels with renewable alternatives, such as hydrogen. Storage and transportation of gaseous hydrogen are key components of large-scale deployment of carbon-neutral energy technologies, especially storage at scale and transportation over long distances. Due to the high cost of deploying large-scale infrastructure, the existing pipeline network is a potential means of transporting blended natural gas-hydrogen fuels in the near term and carbon-free hydrogen in the future. Much of the existing infrastructure in North America was deployed prior to 1970 when greater variability existed in steel processing and joining techniques often leading to microstructural inhomogeneities and hard spots, which are local regions of elevated hardness relative to the pipe or weld. Hard spots, particularly in older pipes and welds, are a known threat to structural integrity in the presence of hydrogen. High-strength materials are susceptible to hydrogen-assisted fracture, but the susceptibility of hard spots in otherwise low-strength materials (such as vintage pipelines) has not been systematically examined. Assessment of fracture performance of pipeline steels in gaseous hydrogen is a necessary step to establish an approach for structural integrity assessment of pipeline infrastructure for hydrogen service. This approach must include comprehensive understanding of microstructural anomalies (such as hard spots), especially in vintage materials. In this study, fracture resistance of pipeline steels is measured in gaseous hydrogen with a focus on high strength materials and hardness limits established in common practice and in current pipeline codes (such as ASME B31.12). Elastic-plastic fracture toughness measurements were compared for several steel grades to identify the relationship between hardness and fracture resistance in gaseous hydrogen.
Prediction of Gas Field Gathering Pipeline Liquid Accumulation and Analysis of Influencing Factors
Authors: Zhang Xinru , Hou Lei , Liu Jiaquan , Zhu Zuoliang
Published: December 2024

Gas field gathering pipeline connects the wellhead and processing station, wet gas gathering process is commonly used in this pipeline. During transportation, the liquid phase is tend to precipitate under low temperature and high pressure conditions, and gradually gather inside the pipeline. Liquid accumulation will reduce pipeline operation efficiency, clog the pipeline, and increase the corrosion rate, which will affect the safe operation of the pipeline. Accurate prediction of the amount and the serious area of liquid accumulation is of great significance for the safety and high efficiency of pipeline. In order to construct a gathering pipeline liquid accumulation prediction model, different saturated water content calculation models are compared to obtain the amount of precipitated liquid, different gas-liquid two-phase flow calculation formulas are compared to obtain the pressure drop and liquid holdup. The accuracy of the model is verified by combining gas field production data and simulation results. The changes of parameters such as pressure and liquid holding rate along the pipeline are analyzed. The influence law of inlet pressure and temperature on fluid accumulation is studied. The results show that the relative error of the calculation results of the liquid accumulation volume of the model is in the range of 1.82%∼5.56%. With the running time, the pressure and the amount of liquid accumulation along the pipeline gradually increase, and the amount of liquid accumulation reaches the maximum value after 243h, and the liquid accumulation is mainly distributed in the rising part of the low-lying pipeline section. The pipeline inlet pressure is directly proportional to the saturated liquid volume and discharge cycle, and inversely proportional to the saturated water precipitation rate. Pipeline inlet temperature is directly proportional to the saturated liquid volume and saturated water precipitation rate, and inversely proportional to the liquid discharge cycle. The prediction model of gas field gathering pipeline fluid accumulation established in this study is reliable and can provide scientific guidance for the prevention and control of pipeline fluid accumulation.
FFS Approach to Assessment of Vibrations Caused by Compressor/Pump Pulsations
Authors: Matta Lawrence M. , Breaux Lyle , Szasz Gyorgy
Published: December 2024

Vibrations in pipeline systems often result from the periodic flow from pumps and compressors, known as pulsations. Due to similarities in the prime movers, pulsations are problematic in both liquid and gas systems. While typically not an issue in long, constant diameter runs of pipeline, pulsation induced vibrations can occur in main transportation lines as well as in supporting systems throughout pumping/compression and treatment facilities.

Standards like API 618 and API 674 are used to provide guidance for predictive analysis to reduce the likelihood of pulsation induced vibrations from occurring. Predictive vibration modeling is very useful for planning purposes, but occasionally surprises occur. The analysis can be sensitive to factors that are not fully known in the design stage. Once in service, facilities may change, equipment may be added, flow rates may be increased, or fluid compositions and temperatures may vary. As a result, pulsation driven vibrations may occur despite predictive analysis.

For operating systems where vibration and pulsation amplitudes can be measured, it is more appropriate to use a FFS (Fitness for Service) approach to determine if mitigations are required and the success of any applied mitigations. While this approach is more involved, it may remove excess conservatism, leading to reduced overall costs.
A Novel Integrated Framework for Evaluating Laminations and Mid-Wall Imperfections in Vintage Pipelines
Authors: Hartl Katherine , Jäger Christoph , Urrea Santiago
Published: December 2024

The presence of mid-wall imperfections, particularly laminations, in pipelines, has been a longstanding concern addressed by pipeline operators for several years. Existing standards and written practices delineate the criteria that render these imperfections actionable, encompassing the intricacies associated with their morphology, while offering guidelines for assessing and ranking their severity. Despite these guidelines, the detection and characterization of complex, non-parallel laminations during in-line inspections (ILI) and in-field non-destructive examinations (NDE) frequently leads to misunderstandings. As a result, mitigation measures often lean towards being overly conservative, resulting in misjudgments that are translated into unnecessary repairs, while potentially leaving truly actionable features unrepaired in service.

By leveraging a database containing data on over one million detected, identified, and sized laminations and applying more than fifteen years of global knowledge accumulation, this paper aims to conduct a thorough gap analysis of existing written practices, with a focus on identifying key areas where misinterpretations commonly occur. The paper will then provide a novel and detailed, step-by-step approach on how to categorize laminations, clearly parametrizing attributes to pinpoint those requiring further assessment, including the proper extraction of their equivalent dimension as a quasi-three-dimensional feature. This process aims to assess whether verification/repair is required under current operational conditions while adopting a holistic approach, where additional factors such as pipeline movement and coincidental anomalies are also incorporated. In addition to these aspects, challenging topics such as assessing the interaction with pipe discontinuities, for example, determining and quantifying the area of weld contact, whether related to a long-seam, girth weld, or spiral weld, will be addressed, providing guidance to better inform and execute Integrity Management Programs.

In conclusion, this paper not only identifies and addresses common pitfalls in current practices but also introduces an innovative methodology for lamination assessments, contributing to a more comprehensive framework for evaluating pipeline integrity.
Soil Springs for Sloped Ground Movement in Saturated Soil
Authors: Eichhorn Geoff N. , Haigh Stuart K. , Baumgard Alex
Published: December 2024

Pipelines buried in sloping ground have not previously incorporated adequately defined soil-springs to represent the reality of forces applied on sloping ground. The soil-spring representation, with its three mutually orthogonal spring pairs, has been developed and defined first by ASCE (1984), and subsequently built on by others. These guidelines were based on physical modelling experiments conducted in the 1970’s and 80’s, and were composed of straight sections of rigid pipe. Those experiments saw the pipe translated relative to the soil in single directions under monotonic movement. The soils studied were largely laboratory (clean sand) and manufactured clays. These experiments define the soil springs for horizontal ground only, and do not necessarily represent the interaction occurring on sloping ground. Physical modelling in a geotechnical centrifuge has been undertaken to study the direct soil-pipe interaction in landslides. Centrifuge modelling recreates scale models in an accelerated gravity field such that the forces, stresses, and physical dimensions are multiplied representing the full-scale equivalent environment. A model pipe representing an NPS 18, ∼X52 line pipe has been designed to allow axial and bending response equivalent to the real-world pipe. Landslides were initiated by elevated pore water pressure, representing above mean seasonal rainfall in upland areas. Pipe strain was monitored using fiber optics and subsurface imaging was used to capture the strain demand (soil displacement) provided by the landslide. Pipe strain was decomposed into bending moment, as well as axial and orthogonal structural forces representing the soil loading on the pipe. Results of the pipe-soil experiments give new insight into the strain transfer between the sloping ground and the pipe. Results show that the peak bending moments shift downslope as the landslide movement progresses. A comparison of American Petroleum Institute (API), DNV, and other industry guidance for springs is made to the pipe-slide interaction results from the physical experiments.
Using Eliminative Argumentation to Enhance Trust in ILI Results
Authors: Casey Adam , Millet Laure , Joyce Jeff , Nachiappan Vijay , Keane Sean
Published: December 2024

Pipeline operators have traditionally relied on unity plots from integrity digs and their confidence in the in-line inspection (ILI) tool vendor as a basis for trust in the results of ILI. However, past digs provide a narrow view of ILI success, and operators have limited visibility into the vendor’s equipment and processes.

In this paper, we describe an analytical approach for the pipeline operator and the tool vendor to collaboratively enhance trust in ILI results. Borrowing methods from safety assurance decision-making in the automotive, rail and nuclear power industries, we present a live and reuseable assurance case framework in eliminative argumentation (EA) produced following this approach. This approach covers all factors impacting inspection results, from identifying required inspection performance to equipment and processes used by the vendor. Safety performance indicators derived from the assurance case can be used as warning signs that adverse events might have occurred during the inspection and that an ILI run might require further examination to confirm the trustworthiness of the results.

We also describe our experience applying this methodology to create an assurance case for an actual ILI program. Our experience demonstrated the benefits of involving the vendor directly in constructing the assurance case. The structure of the assurance case clearly defines the causal connection or “golden thread” between the evidence (including indicators) and trust in the inspection. This traceability allows the operator to differentiate between minor deviations from the norm that do not impact the trustworthiness of the ILI results, and anomalies that are of greater concern. Overall, this approach yields a comprehensive, robust, and examinable basis for trust in ILI results while reducing reliance on integrity digs.
An Innovative Simulation-Free Approach for Probabilistic Assessment of Buried Pipeline Integrity Under Landslide-Induced Ground Movement
Authors: Taraghi Pouya , Li Yong , Yoosef-Ghodsi Nader , Kainat Muntaseer , Adeeb Samer
Published: December 2024

Buried pipelines serve as reliable conduits for transporting energy products such as oil, gas, and chemical fluids. Their pivotal role in facilitating the transportation of these resources underscores their substantial impact on businesses, economies, and the overall quality of life for people. Landslide-induced ground movement poses a risk to buried pipelines, potentially causing buckling damage or tensile rupture, threatening their structural integrity and operational safety. Hence, it is crucial to investigate the response of buried pipelines to mitigate the potential impacts of landslide-induced ground movement. However, due to the uncertainties in material, geometry, soil properties, and ground movement, it is imperative to conduct reliability-based analyses rather than deterministic analyses. Reliability methods like Monte Carlo, known for their simplicity and effectiveness, are widely used in reliability analyses. However, their significant drawback lies in the need for extensive simulations to generate responses, a challenge that proves impractical for studying pipelines buried through areas prone to ground movement. As such, this study introduces an innovative simulation-free approach based on the Physics-Informed Neural Network (PINN) to predict the response of inelastic pipelines under landslide-induced ground movement. Using the simulation-free approach for response predictions, the Monte Carlo simulation is then employed to determine the probability of failure. PINN offers a comprehensive solution to the underlying physics of the problem by incorporating stochastic variables like ground movement and eliminating the need for an extensive number of simulations to obtain the response. PINN utilizes a deep learning approach that operates without the need for training data by leveraging the underlying physics expressed through differential equations. The applicability of the employed method to pipelines subjected to permanent ground movement is demonstrated through a case study. The strain-based limit state function relies on established equations from the literature for determining strain capacity, while the strain demand is predicted using the PINN-based approach.
Constraint-Independent Constant CTOA Determination for Ductile Stable Crack Growth
Authors: Zhu Xian-Kui
Published: December 2024

Crack tip opening angle (CTOA) has been used as a reliable fracture toughness parameter for decades to characterize stable ductile crack growth for thin-walled aerospace structures in the low-constraint conditions. Recently, the CTOA parameter was also applied to the pipeline industry, and a CTOA test standard ASTM E3039 was thus developed for testing a critical constant CTOA. Research showed that the constant CTOA can reasonably describe fracture toughness required to arrest a dynamic crack propagation for a modern gas pipeline. However, the CTOA fracture criterion requires constraint-independent CTOA toughness against stable ductile crack growth.

ASTM E3039 recommends a drop weight tearing test (DWTT) specimen for CTOA testing. Since a shallow crack is used, DWTT measured CTOA may depend on constraint level at the crack tip. To understand if it is the case, this paper evaluates the critical CTOA for a set of fracture toughness tests on single edge notched bend (SENB) specimens with shallow and deep cracks based on four CTOA estimation models. In which, the Ln(P)-LLD linear fit model is similar to that used by ASTM E3039 in the CTOA calculation. Fracture test data for X80 pipeline steel and HY80 structural steel are considered in the CTOA evaluation. The results show that the four CTOA models can determine a crack size-independent constant CTOA over stable ductile crack growth for the SENB specimens. As a result, CTOA determined by ASTM E3039 is constraint-independent and transferable to use for an actual crack propagating in a gas pipeline.
Extra-High-Resolution UTCD Solution for Small-Diameter Pipelines – Introducing Extended Depth Sizing
Authors: Atto Abdullahi , Klinge Lukas , Bauer Stefan , Beuker Thomas
Published: December 2024

Depth sizing beyond 4 mm for crack-like anomalies has been made available recently for large-diameter ILI tools. For small-diameter pipelines (OD ≤ 12 inches), additional challenges to the measurement performance had to be considered and addressed by the inspection tool design before an extended depth sizing could be provided in a robust and reliable manner.

The sharp circumferential curvature of small-diameter pipes has a focusing effect on the ultrasonic beam, thus altering the characteristics of the sound pressure distribution and signal strength. For small-diameter pipelines, the ultrasound propagation angle in the pipe wall can significantly differ for internal and external axial anomalies because of the difference between the curvature radius of the outer and inner pipe surface (OD vs. ID).

Small-diameter pipelines generally have a limited tolerance for variations of the incidence angle. Therefore, UT-C inspections of small-diameter pipes are generally more sensitive to the operating conditions and to sound velocity variations of the coupling medium (due to temperature variations during the run).

This article discusses the above limitations in detail and presents technical solutions for realizing high-performance UT-C tools for small-diameter pipelines. Furthermore, the paper presents the performance qualification procedure and results of new generation of extra-high-resolution UTCD tools for 6″, 8″ and 10″ pipeline diameters.

The UTCD performance qualification is based on so-called “extended depth sizing” method, resulting in discrete depth sizing even for anomalies deeper than 4 mm. This method incorporates both direct and indirect corner echo amplitudes into the depth sizing.
Understanding Security Program Risk Assessments Through a Secure Asset Framework
Authors: Zhao Lisa , Nairn Jamie , Jean Mark
Published: December 2024

The energy industry is responsible for critical infrastructure that keeps individuals, public services, and private industry functional and safe. Industry threats are constantly evolving and require robust security controls to protect people, assets, the environment, and operations. As organizations automate processes to increase operational efficiency, assets are becoming more interconnected, and security programs are increasingly tasked with protecting more interconnected assets than ever before. These programs need to be flexible enough to manage evolving security risks, vulnerabilities, and threats to the company, while meeting regulatory compliance requirements. By establishing a secure asset framework (SecureAF), a company can be prepared to anticipate future security challenges in the current threat landscape. This proactive stance enables safe and sustainable business growth in an interdependent and technologically connected world. Security programs protect assets from threats such as terrorism, violence, sabotage, and theft by proactively assessing and managing physical, cyber, and cyber-physical risks. Security risks are particularly unique and challenging to manage because they are constantly changing and evolving in scope and consequence. As a result, organizations are becoming increasingly vulnerable to attacks. Identification of critical security risks safeguards personnel, operations, and critical assets, and enables achievement of business objectives. In turn, integrated planning ensures a fortified, comprehensive security program.

SecureAF provides the structure for cyber and physical security programs to meet their objectives and protect people, assets, and the environment. This paper will focus on the security risk assessment component of the framework, and how security risks can be effectively managed and aligned to corporate risk management.
Methodologies for Conservation and Maintenance of Anchored Retaining Walls
Authors: Dada Thais Lucouvicz , Neves Douglas de Andrade , Guimarães Neto João Duarte , Russo Junior Wanderley Camargo , Leite Roberta Amorim , Santos Thiago da Costa , Spagnolo Rodrigo Alves
Published: December 2024

Brazil has a wide mesh of pipelines, of which more than 8,500 kilometers are operated by TRANSPETRO. Pipeline right-of-ways cross a variety of soil relief, including the Serra do Mar, a formation of scarps, in order to transport petroleum products from the coast to the largest cities in the country. Anchored retaining walls are commonly necessary for soil stabilization. An efficient risk management is required for these structures, to avoid social, economic and environmental damages in case of poor performance.

A case study of 77 anchored walls was presented. It was shown that is possible to manage a large number of structures, with a large variability in age, including structures until approximately 60 years old.

All standards recommend geotechnical instrumentation. Parametric numerical analysis where performed for guiding instrument location. A distance of 0.25H from the wall, where H is the wall high, was suggested to install the inclinometer, in order to monitor soil displacements behind the wall. However, when there is another purpose, such as to monitor the entire slope or highways near the ROWs, geotechnical instrumentation can be installed according to these necessities.

Based on a bibliographic review, a case study and on numerical analysis results, a summary of a long-term maintenance program for anchored walls was presented. The program aims to implement risk management for large numbers of structures. With that, it is possible to guarantee operational conditions to all and increase the service life for older structures.
Effect of Longwall Mining on Exposed Pipelines: FEA Vs Measured Stresses
Authors: Zand Benjamin , Dugan Brett
Published: December 2024

With coal and natural gas extraction often occurring in similar regions, pipeline operators are often forced to navigate the complexities of mine subsidence beneath their pipelines. Longwall mining operation has the potential to compromise the integrity of buried pipelines by creating high soil strains. Mitigation measures often include pipeline excavation and a strategic pipeline strain monitoring program to ensure that stresses on pipelines do not exceed allowable limits. In this research a comparison is made between the finite element analysis results versus measured strains in an exposed pipeline subjected to longwall mining subsidence in the Midwest. Strain gauges were attached to the exposed pipeline before subsidence was experienced to monitor changes in the strain throughout the duration of the subsidence event. Simultaneously, ground displacements were monitored by performing regular ground surveys. A soil-pipe interaction finite element model was developed to calculate pipeline strains based on calculated ground displacements using the Influence Function model.

This paper compares the calculated strains from the finite element analysis to the actual strains measured by the strain monitoring system. Data from the case study are presented and compared.