bluuebunny/crossref_metadata_2025 huggingface dataset:
Integrity Assessment of Pipelines With Ovality
Authors: Zhang Fan , Rosenfeld Michael
Published: November 2018

Ovality in a pipe results in a stress concentration and may present a pipeline integrity concern. If ovalization is generated during manufacturing or transportation and found during the girth welding process before the pipe is buried, replacement of the oval segment is usually the solution. However, ovalization is sometimes also found in buried pipelines via in-line-inspection (ILI) either before the pipeline is put into service or during regular pipeline maintenance. The mitigation and/or replacement of oval pipes after burial can be expensive. It is vital to identify what constitutes an unacceptable ovality level and to remediate only those that pose a threat of failure during the service life of the pipeline. The existing assessment approaches for oval pipes, such as that in API 579, generally require knowledge of the amount of ovality at zero pressure. However, the ovality of buried pipes usually is only available from ILI runs carried out at a non-zero internal pressure. The internal pressure tends to push the pipe back toward a circular shape, a phenomenon known as re-rounding. As a result, the ILI-reported ovality is smaller than that under zero pressure. Described in this paper is a new approach which can be used to assess the integrity of oval pipe segments based on ovality either as measured with no pressure in the pipe or as reported by ILI conducted at an elevated level of pressure. The approach considers both burst failure and fatigue damage. The accuracy of the approach was verified by finite element analysis (FEA). With the help of this new approach, a general discussion about the threat of ovalization to the integrity of a pipeline is provided. The analysis indicates that ovalization in amounts usually observed does not reduce the burst pressure in most pipelines, but fatigue damage could be a concern. The fatigue damage due to ovalization is sensitive to pipe geometry, amplitude of pressure variation, and the minimum pressure level within the pressure cycles.
Accelerating Industry Performance Through Collaborative Continual Improvement
Authors: Lukaniuk Coral , Coupal Chris
Published: November 2018

CEPA Integrity First® (Integrity First), led by the Canadian Energy Pipeline Association (CEPA) and a condition of membership, acts as a foundation for continual improvement, bringing our members together to share and implement leading practices in the areas of safety, environment and socio-economics. Integrity First includes three principles and ten priority areas (such as emergency management, pipeline integrity and water protection) where members collaborate, share leading practices and hold each other accountable.

Integrity First is a management systems approach designed by CEPA members for industry to achieve collaborative continual improvement. It supports the collective setting of priorities, plans, assessments and improvements.

While spreadsheets enabled the first rounds of assessments, CEPA required a solution that engaged multiple stakeholders over a complex timeline, coordinated activities clearly and precisely, while keeping the process transparent and efficient. The information generated is sensitive, so it must be kept secure while still being available for aggregation, reporting and reference. It needed to house communication tools so members could easily pull information and lastly, it needed to be easy to use.

In August of 2015, CEPA established a partnership with SPAN Consulting (SPAN) to address these challenges through its software as a service (SaaS) offering called Octane™.

This paper will review how CEPA designed and implemented a technical, web-based solution to enable an efficient, effective and transparent Integrity First with transformative impact. Specifically, through the use of this technology, there are now stronger communities of practice across industry with increased focus and effort on the opportunities to improve through real-time self-serve access to industry’s overall benchmarked performance, leadership and leading practices. CEPA’s commitment to enabling Integrity First is resulting in better adoption and improved performance.
An Investigation of the Load Carrying Capacity of Pipelines Under Accidental and Longitudinal Moving (Sliding) Loads
Authors: Davaripour Farhad , Quinton Bruce W. T.
Published: November 2018

In accidental scenarios on subsea pipeline systems, like the collision of two adjacent subsea risers, accidental loads are commonly considered as stationary loads; stationary loads refer to loads that act only normal to the pipe at one location. Hence, the potential considerable effects of moving (sliding) accidental loads are neglected; the term moving load refers to the location with respect to time. Accordingly, recent works for ship hull structures show that the structural resistance mobilized against the moving loads is significantly lower than against the stationary loads of similar magnitude; when the loads incite plastic damage. As such, it is reasonable to study the effects of lateral motion of accidental loads on the response of subsea pipelines. This paper implements finite element analyses to investigate the load carrying capacity of a cylindrical shell subject to moving loads; LS-Dyna software package with explicit time-integration scheme is employed in numerical simulations; only crumpling deformation of the cylinders are studied. This research demonstrates that the capacity of a cylindrical shell subject to a moving load, causing plastic damage, is considerably less than its capacity under a stationary load of similar magnitude.
Evolving Standards of Indigenous Peoples Engagement and Managing Project Risk
Authors: Vincent Bruce D. , Maharaj Indra L.
Published: November 2018

The standards for Indigenous engagement are evolving rapidly in Canada. The risks to project approvals and schedules, based on whether consultation has been complete, have been recently demonstrated by the denial of project permits and protests against projects. Indigenous rights and the duty to consult with affected Indigenous groups is based on the Constitution Act, 1982 and has been, and is being, better defined through case law. At the same time, international standards, including the International Finance Corporation Performance Standards and the United Nations Declaration on the Rights of Indigenous Peoples, are influencing government and corporate policies regarding consultation. The Government of Canada is revising policies and project application review processes, to incorporate the recommendations of the Truth and Reconciliation Commission of Canada; that Commission specifically called for industry to take an active role in reconciliation with Canada’s Indigenous peoples. Pipeline companies can manage cost, schedule and regulatory risks to their projects and enhance project and corporate social acceptance through building and maintaining respectful relationships and creating opportunities for Indigenous participation in projects.
Predicting Monthly Energy Consumption of Crude Oil Pipelines Using Process Simulation and Optimization
Authors: Zuo Lili , Wu Changchun , Liu Song , Jiang Yong , Zhang Xiaorui
Published: November 2018

Based on process principles and the operational features of crude oil pipelines, this research developed mathematical models to optimize steady-state pipeline operation, to apportion monthly flow into daily or hourly flow rates, and to predict monthly energy consumption. Corresponding algorithms were also developed. Because these models and corresponding algorithms are process-based, they are suitable for predicting monthly energy consumption of existing isothermal and hot crude oil pipelines. The predicted monthly energy consumption of crude oil pipelines depends on which flow distribution method is used, which pumping operation scheme is used and which heating operation scheme is used, with different flow distributions, different pumping and heating operation scheme yielding a range of monthly energy consumption predictions for a given transportation volume. The minimum monthly energy consumption can be determined from these predictions, and the interval of the predictions can indicate the extent to which the flow rate fluctuation affects pipeline energy consumption. Both of these findings can be used by pipeline operators to reduce the amount of energy needed to operate crude oil pipelines.
A Novel Depth-First Searching Approach for Detailed Scheduling of Operations in a Multi-Product Pipeline With Multiple Pump Stations
Authors: Liao Qi , Wang Bohong , Li Zhengbing , Zhang Haoran , Liang Yongtu , Liang Jun
Published: November 2018

Considering market’s diversified demand and transport economy, large volumes of various refined products commonly move down the pipeline in batches, which are pumped at pump stations and delivered to respective delivery stations. The integrate detailed scheduling optimization is a sophisticated problem due to the characteristics of multi-product pipelines, such as market-oriented, fluctuated demand, various processing technique and complicated hydraulic calculation during batch migration. The integrate detailed scheduling optimization has been widely studied during the last decade, however, most of them studied pipeline scheduling and pump scheduling separately. Besides, the proposed methods are mathematical models, whose computational efficiency greatly decreases in large-scale pipeline scheduling, let alone in the problems coupling with pump scheduling.

Aiming at this problem, this paper presents a novel depth-first searching approach based on flowrate ratio to deal with the detailed scheduling of operations in a multi-product pipeline with multiple pump stations. As for each single time interval, the proposed method decides an ideal flowrate ratio according to current status, then solves out the optimal flowrate that mostly conforms to the ideal ratio and satisfies all operational constraints, and finally updates information for next time interval. However, during the computational procedure, backtracking method would be adopted to modify the previous flowrate ratios and recalculate new flowrate when the actual delivered products are insufficient. Finally, a case tested on a Chinese real-world pipeline with 6 delivery stations is given to demonstrate the veracity and practicability of the proposed method. From the results, computing time of the case is within 1 minute, and the solved detailed scheduling plans can fulfill demand with stable pump operations. Besides, the proposed approach is scarcely influenced by the scale of pipeline structure and time horizon, so it is also applicable to the long-term scheduling of a pipeline with many delivery stations.
Methodologies for Establishing the Probability of Pipeline Failure at Slope Crossings
Authors: Sen Millan , Hassanien Sherif , Cormier Yves , Koduru Smitha
Published: November 2018

Pipelines in transmission pipeline networks often traverse land slopes along the right-of-way; especially near water crossings. While the vast majority of these slopes are stable, some might have a potential for instability related movements. Accordingly, pipelines subjected to these movements are susceptible to strain overload which may cause loss of containment in terms of buckling and/or tensile elongation failure modes. In order to analyze the risk of failure of pipelines due to slope movement it is beneficial to establish probabilistic approaches that can predict the likelihood of failure at each site given both aleatory and epistemic uncertainties. Estimation of such likelihood would support prioritization of integrity mitigation actions and confirm pipelines’ safety. There is a gap in pipeline literature in terms of available probabilistic approaches to analyze, assess, and manage such an integrity threat. Two probabilistic approaches are presented herein; a qualitative ranking analysis of slope hazards (QuRASH) and a semi-quantitative analysis of slope hazards (SQuASH). QuRASH is a qualitative approach that adopts site scores based on available slope characteristics, historical movements, expert opinion, and mitigation strategies. SQuASH is a reliability-based explicit limit state approach. Both approaches were applied to a large simulated sample of slope crossings that exhibit characteristics representative of North America transmission pipeline slope crossings. The resulting probabilities of failures were directly compared to those predicted based on expert judgement. The high ranked sites compared favorably with those evaluated by experts to exhibit elevated threats. This successful comparison provides a certain level of confidence in the proposed approaches.
Pipeline Data Analytics: Enhanced Corrosion Growth Assessment Through Machine Learning
Authors: Smith Michael , Cronjaeger Stefan , Ershad Navid , Nickle Randy , Peussner Matthias
Published: November 2018

Effective integrity management of a corroded pipeline requires a significant quantity of data. Common data sources include in-line inspection (ILI), process monitoring, or external surveys. The key challenge for an integrity engineer is to leverage the data to understand the level of corrosion activity along the pipeline route, and make optimal decisions on future repair, mitigation and monitoring. This practice of gaining business insights from historical datasets is often referred to as ‘data analytics’.

In this paper, a single application of data analytics is investigated — that of improving the estimation of corrosion growth rates (CGRs) from ILI data. When two or more sets of ILI data are available for the same pipeline, a process known as ‘box matching’ is typically used to estimate CGRs. Corresponding feature ‘boxes’ are linked between the two ILIs and a population of CGRs is generated based on changes in reported depth. While this is a well-established technique, there are uncertainties related to ILI sizing, detection limitations, and data censoring. Great care is required if these uncertain CGRs are used to predict future pipeline integrity.

A superior technique is ‘signal matching’, which involves the direct alignment, normalization and comparison of magnetic flux leakage (MFL) signals. This delivers CGRs with a higher accuracy than box matching. However, signal matching is not always feasible (e.g. when conducting a cross-vendor or cross-technology comparison). When box matching is the only option for a pipeline, there is great value in understanding how the box matching CGRs can be improved in order to more closely resemble those from signal matching. This limits the extent to which uncertainties are propagated into any subsequent analyses, such as repair plan generation or remaining life assessment.

Given their relative accuracy, signal matching CGRs can be utilized as a ‘ground truth’ against which box matching results can be validated. This is analogous to the ILI verification process, where in-field measurements (e.g. with laser scan) are used to validate feature depths reported by an ILI. By extension, a model to estimate CGRs following a box matching analysis can be trained with CGRs from a signal matching analysis, using supervised machine learning. The outcome is an enhanced output from box matching, which more closely resembles the true state of corrosion growth in a pipeline.

Through testing on real pipeline data, it is shown that this new technique has the potential to improve pipeline integrity management decisions and support economical, safe and compliant operation.
A Multi-Module Systemic Approach for the Supply Reliability Analysis of Multi-Product Pipeline Under Pump Units Failure
Authors: Zhou Xingyuan , Liao Qi , Lv Mengyun , Zhang Haoran , Liang Yongtu , Xiang Chengcheng
Published: November 2018

As the primary means of refined products transportation, multi-product pipeline plays a vital role in connecting refineries to local markets. Once disruptions occur, it will cause security issue on oil supply to downstream markets, even on the economy and stability of society. Based on the conventional reliability theory and detailed scheduling method of multi-product pipeline considering hydraulic constraints, this paper firstly proposes a multi-module systemic approach for the supply reliability analysis of multi-product pipeline under pump units failure conditions. Pump units are important corollary equipment in multi-product pipeline and their failure would affect the pipeline normal operation and downstream oil supply greatly. The approach includes three modules, namely, pump units analysis module, pipeline system analysis module and reliability evaluation module. In the pump units analysis module, Failure Mode and Effects Analysis (FMEA) method is adopted to analyse the correlations between pump units failure modes and causes. The Monte Carlo simulation method is employed to generate different failure scenarios based on the estimated failure rate of pump units. In the pipeline system analysis module, the detailed scheduling method of multi-product pipeline is adopted to calculate the maximum supply capacity for all delivery stations under a specific scenario. Due to the difficulty in solving detailed scheduling problem considering hydraulic constraints directly, two mixed integer linear programming (MILP) models are established. In the reliability evaluation module, the indexes of shortage, probability and adequacy are calculated to analyse the supply reliability quantitatively from global perspective and individual perspective. Finally, the proposed approach is applied to a real-world multi-product pipeline in Zhejiang, China. It is proved that this approach could provide significant guidelines for the supply reliability analysis of multi-product pipeline.
Using 2D and 3D Oil Spill Trajectory and Fate Models to Assess the Risk of Accidental Crude Oil Releases Along the Enbridge Line 3 Replacement Program Pipeline
Authors: Horn Matthew G. S. , Fontenault Jeremy M.
Published: November 2018

The proposed Enbridge Line 3 Replacement Program would replace the aging pipeline from Hardisty, Alberta, Canada to Superior, Wisconsin, USA. For the Canadian route, an Ecological and Human Health Risk Assessment (EHHRA) was prepared for the National Energy Board (NEB) in Canada. In the United States, an Assessment of Accidental Releases (AAR) and the Supplemental Release Report were part of an Environmental Impact Statement (EIS) prepared for the Minnesota Public Utilities Commission (PUC) and Minnesota Department of Commerce, Energy Environmental Review and Analysis (DOC-EERA).

Computational oil spill modeling was used to assess the predicted trajectory (movement), fate (behavior and weathering), and potential effects (impacts) associated with accidental releases of crude oil along the proposed pipeline. This modeling included the 2-dimensional OILMAPLand and 3-dimensional SIMAP models. A total of 64 hypothetical release scenarios were investigated to understand the range of potential trajectories, fates, and effects that may be possible from multiple product types (Bakken, Federated Crude, and Cold Lake Winter Blend), released at any location, under varying environmental conditions.

Trajectory and fate modeling was used to predict the downstream movement and timing of oil, as well as the expected surface oil thickness, water column contamination, shoreline and sediment oiling, and proportion evaporated to the atmosphere. These results were then used to assess the potential environmental effects to demonstrate the variability of outcomes following a release under different release conditions.
Risk-Based Integrity Decision Making for Lateral Piping
Authors: Kulhawy Amanda , Nemeth Alex , Sommer Garry , Hassanien Sherif
Published: November 2018

Integrity reliability science plays a major role in the integrity management of transmission piping, which is piping that traverses long distances across the continent, at high pressures, and can experience high pressure cycling. This science can be applied to non-transmission piping such as lateral piping, which traverses between a transmission line and a facility, or between two facilities, at lower pressures and with lower pressure cycling. Laterals are susceptible to the same threats as transmission lines (internal corrosion, external corrosion, cracking, geotechnical hazards, etc.). However, due to their operation, laterals are only highly susceptible to internal and external corrosion. While site specific conditions may result in a high susceptibility of a geotechnical hazard, this threat is outside of the scope of this paper. On transmission piping, corrosion is generally managed with In-Line Inspection (ILI), Non-Destructive Examination (NDE), and corresponding repairs (e.g. sleeving) to assess and mitigate. With laterals, there can be limited ILI and NDE data. As such, the data used in the quantitative reliability framework for these threats is not available and this creates a gap in the process. This paper addresses this gap through the application of semi-quantitative reliability analysis for internal and external corrosion on laterals along with a risk-based integrity decision making framework. The proposed approach is designed to enable pipeline and facility operators to make effective decisions around lateral integrity programs given the available data, and to better understand the limitations of integrity decision making. Moreover, the paper expands the discussion around the difference between risk-informed and risk-based integrity decision making in order to provide a guideline for optimal and safe integrity management programs considering different criteria. Case studies that include limited or no ILI or NDE information are used to demonstrate the application of semi-quantitative and quantitative reliability assessment of laterals along with the exploration of challenges in calibrating the two assessment methods to provide an example of how reliability science can be applied to laterals and how this can be used in effective decision making given such limitations.
Quantification of Splitting in X80 Pipeline Steel
Authors: Gervasyev Alexey , Petrov Roumen , Pyshmintsev Igor , Huo Chunyong , Barbaro Frank
Published: November 2018

The results of in-depth analysis of microstructure and crystallographic texture of several industrial batches of line pipes with known full-scale burst test results are presented. Several microstructural features promoting splitting are highlighted and quantified using electron back-scattered diffraction (EBSD) data. The actual splitting intensity is evaluated by means of Charpy tests in the direction of pipe wall thickness (Z-direction) and correlates with the microstructural parameters determined by EBSD analysis. This knowledge can be used in the design of thermo-mechanical controlled processing (TMCP) dedicated to production of splitting-free steel.
High pH Crack Growth Sensitivity to Underload-Type of Pressure Fluctuations
Authors: Niazi Hamid , Zhang Hao , Korol Kaitlyn , Chen Weixing
Published: November 2018

High pH Stress Corrosion Cracking (HpHSCC) is a significant threat to the buried pipelines, which are protected through simultaneous coating and cathodic protection strategies. In the past decades, extensive research has been devoted to assessing the influence of environmental and metallurgical factors on the susceptibility to HpHSCC. With reference to mechanical factors, previous studies employed either slow strain rate or constant amplitude testing methods. However, the pressure fluctuation data extracted from pipeline operations has indicated that pipelines experience highly variable amplitude loading conditions during their service. Accordingly, an important consideration in managing HpHSCC is load interaction. Statistics show a higher probability of HpHSCC failures within the 30 km downstream from pump/compressor stations where the pipeline steels experience elevated service temperatures, with incipient higher susceptibility to HpHSCC. However, the pipeline sections within the 30 km downstream from pump/compressor stations also experience the underload-type of pressure fluctuations that feature a maximum pressure close to the design limit, frequent and large amplitudes of depressurization, resulting in low stress ratio, R (minimum stress/maximum stress), and many smaller pressure fluctuations (minor cycles) with R ratio closer to +1.0. It has been well characterized that the underload-minor-cycle-type of pressure fluctuations has the significant acceleration effect on crack growth rates in near-neutral pH (NNpH) environments. However, the effect of the underload-type of pressure schemes on HpHSCC crack growth has not been well developed. In this research work, a cathodically protected X65 steel specimen in the developed high pH solution, composed of 1N Na2CO3 and 1N NaHCO3, was subjected to different loading conditions. These loading waveforms simulate underload cycles (R = 0.5), minor cycles (R = 0.9) and variable amplitudes consisting of both underload and minor cycles, respectively. The HpHSCC test results showed that the highest and lowest crack growth rates were obtained in high and low R ratio constant amplitude loading conditions, respectively. Furthermore, an intermediate crack growth rate was obtained under variable amplitude loading condition. These results indicate that the underload cycles retard crack growth rate in high pH environments.
In-Situ Modal Response Characterization of Pipe Structures Through Reynolds Number Variation
Authors: Chen Haobin , Hugo Ron , Park Simon
Published: November 2018

The modal response characterization of structures is a proven and reliable technique used to monitor system behavior and change, providing information for condition assessment and damage identification. In traditional modal response characterization procedures, an external mass excitation source is used to excite the system, and this is modeled as an impact function. This provides system forcing across a broad range of frequencies. In this investigation, an in-situ method of system excitation is explored. The modal characteristics of externally-supported pipe structures are investigated by varying the flow Reynolds number (Red). Given the increase in flow turbulence with Reynolds number, hydrodynamic pressure fluctuations on the pipe wall provide a varying excitation source. This removes the requirement for an external excitation source.

A comparative analysis of data sets collected for both Acrylic and ABS pipe material show similar pressure spectra, while vibration spectra change significantly. Pressure spectra reveal a character whereby the spectral energy increases with increasing Reynolds number. A comparison of in-situ results to those obtained using traditional impact response tests show that vibration spectra collected through Reynolds number variation successfully capture the modal characteristics of the pipe-structure.
Evaluation of the Fatigue Crack Growth Behavior by Experiments and Numerical Simulations on Full-Size Pipeline Steels
Authors: Hjiej Siham , Osipov Nikolay , Lebrun Adrien , Soret Clement , Madi Yazid
Published: November 2018

The safety of gas transportation pipelines under fatigue loading remains an important issue. The purpose of the present study is to better evaluate the fatigue crack growth (FCG) behavior by carrying out analysis/predictions and experiments in full-size pipeline steels. A full characterization was made using several samples of an X42 grade pipeline steel, to characterize the monotonic and the fatigue behavior. Fatigue tests on full-scale pipeline steels under pressure loading were performed. The potential drop (PD) method applied to pressurized pipes makes it possible to monitor and quantify both crack initiation and crack propagation. These tests served as a basis for numerical comparison. Crack propagation of the full-size pipeline steel was simulated by finit element analysis (FEA) using an adaptive re-meshing approach implemented as part of the Z-set/Zebulon software. Simulation allows predicting fatigue crack growth life on pipes using results of tests on specimens as an input.
Structure Formation Control of Microalloyed Pipe Steels During TMCP for Enhanced Low Temperature Toughness
Authors: Dmitrii Ringinen , Andrei Chastukhin , Leonid Efron
Published: November 2018

A continuous demand for plates for X60-X120 pipes with high toughness and cold resistance requires the development of new methods of additional grain refinement at all stages of thermo-mechanical control processing (TMCP). An effect of structure formation during slab reheating was studied. Physical models of secondary recrystallization during reheating and austenite recrystallization at roughing rolling of Nb-microalloyed pipeline steels were developed. Grain refinement in the course of hot deformation was studied through physical modeling. Using the recrystallization model, new rolling schedules were introduced. Industrial trials were conducted; the effect of reheating and deformation parameters on cold resistance of steel was investigated. Implementation of the results of given study into production practice made it possible to produce plates with excellent properties, including strength, toughness, and cold resistance.
CO2SAFE-ARREST: A Full-Scale Burst Test Research Program for Carbon Dioxide Pipelines — Part 1: Project Overview and Outcomes of Test 1
Authors: Linton Valerie , Leinum Bente Helen , Newton Robert , Fyrileiv Olav
Published: November 2018

Transport of anthropogenic carbon dioxide in pipelines from capture site to storage site forms an important link in the overall Carbon Capture, Transport and Storage (CCTS) scheme. The thermodynamic properties of CO2 are different from those of other gases such as natural gas that are transported in pipelines. Recent full-scale burst tests from the projects SARCO2 and COOLTRANS indicated significant variations in correction factors necessary to predict the arrest of a running ductile fracture. In addition, CO2 can be a potential hazard to human and animal life and the environment. While consequence distances of natural gas pipelines are well established and documented in standards, this is not the case with CO2.

The research focused CO2SAFE-ARREST joint industry project (JIP) aims to (1) investigate the fracture propagation and arrest characteristics of anthropogenic CO2 carrying high strength steel pipelines, and (2) to investigate the dispersion of CO2 following its release into the atmosphere. The participants are DNV GL (Norway) and Energy Pipelines CRC (Australia). The project is funded by the Norwegian CLIMIT and the Commonwealth Government of Australia. The joint investigation commenced in 2016 and will continue to 2019.

The experimental part of the project involves two full-scale fracture propagation tests using X65, 610mm (24“) pipe and two 6″ shock tube tests, with all tests filled with a dense phase CO2/N2 mixture. The full-scale tests were made up of 8 pipe lengths each, with nominal wall thicknesses of 13.5 mm and 14.5mm. The dispersion of the carbon dioxide from the full-scale test sections was measured through an array of sensors downwind of the test location. The tests were conducted in 2017/2018 at Spadeadam, UK.

Following a short review of the background and outcomes of previous CO2 full-scale burst tests, this paper provides insight on the aims of the overall experimental program along with summary results from the first full-scale fracture propagation test, carried out in September 2017. Two companion papers provide further details on the first test. The first companion paper [IPC2018-78525] discusses the selection of pipe material properties for the test and the detailed fracture propagation test results. The second companion paper [IPC2018-78530] provides information on the dispersion of the CO2 from the first full-scale test, along with numerical modelling of the dispersion.
Recommendations for Submerged Arc Spiral Welding With Optimized CTOD Properties
Authors: Liebeherr Martin , Güngör Özlem E. , Sanchez Nuria , Luccioni Hervé , Ilic Nenad
Published: November 2018

Many pipe mills may not be familiar with a Crack Tip Opening Displacement (CTOD) requirement on the pipe seam weld, nor will they find easily relevant information in open literature. Influencing — and certainly not independent — factors are: welding parameters, base material and consumable selection. Out of these, the welding parameters such as heat input and cooling rate cannot be varied over a wide range during the pipe production, which means that the leverage is rather limited at the given welding process. The properties of the heat affected zone will be mainly affected by the base material, while the properties of the weld metal will be affected by both, base material and filler wire selection. In particular with respect to the weld metal properties it will be difficult to obtain general quantitative information. For example, a welding consumable supplier will readily provide the properties of the filler wires but would be unable to predict the changes caused by the dilution from any base material in the weld pool and specific welding procedures that may have been used.

To support the pipe mills in the selection of the consumables for submerged arc welding, an experimental program was launched with the aim to provide recommendations on how to optimize CTOD toughness of the spiral weld seam. For this, a large number of welds were produced on 20 mm thick X70 coil samples, with eight different filler wire combinations, using a 2-wire (tandem) set-up for both the inside and outside weld. Welding parameters were kept constant. The welding program was applied to two different X70 steels to determine a potential influence of the micro-alloying elements, particularly Nb.

The results show clearly that a careful consumable selection is required for obtaining acceptable CTOD toughness in the weld metal. Ni-Mo and Ti-B additions to the weld metal are found to be beneficial with both steel concepts. Mo addition alone both to the ID and OD welds was clearly not a suitable selection.
Using Alternate Technologies and Advancements Through Special Permits, Waivers, and Other Technology Notifications
Authors: Lee Kenneth Y. , Secor M. “Buddy”
Published: November 2018

The United States Department of Transportation (USDOT), Pipeline and Hazardous Materials Safety Administration (PHMSA), Office of Pipeline Safety recognizes there may be technologies and advancements not currently allowed by the federal regulations that can improve safety, and has processes to allow such technologies and advancements. These processes include Special Permits, State Waivers, and Other Technology Notifications. This paper describes observations and trends related to PHMSA’s accumulated data from the last few decades, and includes a summary of new technologies and innovative solutions that are not currently covered in codified standards or regulations.1
Limit States Design Checks for Geotechnical Loads
Authors: Nessim Maher A. , Koduru Smitha D.
Published: November 2018

A limit states design approach has been developed for geotechnical loads. The approach uses a strain based design format and requires the user to develop probability distributions for the maximum strain demand and minimum strain capacity. Checks are provided for both local buckling and tensile rupture, which are calibrated to meet specified risk-consistent reliability targets. The safety factor and the criteria used to define the characteristic strain demand and capacity are defined as functions of the reliability target and the coefficients of variation of the strain demand and capacity. The checks are calibrated for a wide range of target reliability levels and distributions to cover most cases related to slope creep, landslides, frost heave and thaw settlement. They can also be applied to seismic deformations, subject to confirmation that the strain demand and capacity distributions fall within the range of calibrated cases. The design checks provide guidance on how to account for the spatial and temporal characteristics of different geotechnical loading processes, including distinction between sudden and gradual load application, and between known and randomly located loading sites. The limit states checks can be used to design new pipelines and assess the safety of existing ones. Application to slope movements is demonstrated by a set of examples.
Understanding Pipeline Strain Conditions: Case Studies Between ILI Axial and ILI Bending Measurement Techniques
Authors: Choquette Jeremie J. , Cornu Sylvain , ElSeify Mohamed , Karé Raymond
Published: November 2018

In-Line inspection (ILI) tools consisting of combined sensor technologies provide a unique opportunity for operators to understand the conditions of pipelines. There is also an additional opportunity to contrast and validate individual sensing techniques against each other when their functionalities and purposes overlap.

By using multi-technologies ILI measurements for strain, a pipeline operator can gain further insight into the pipeline strain behavior at any point along the length of the inspection. This paper establishes the relationship between ILI axial strain measurement tool data and conventional geometric strain data obtained from inertial measurement unit (IMU) based on data collected during in-service inspection of a 12″ liquid pipeline.

Within any pipeline section, the tool configuration with circumferentially spaced strain sensors allows the use of appropriate analysis techniques to decompose the longitudinal strain into its primary components (axial, bending and out of roundness).

The axial strain measurement tool sensing system provides an indirect measurement of bending strain that can be compared to the geometric measurement of bending strain determined from the pipeline trajectory as determined from the IMU analysis. Flexural bending strain resulting from horizontal directional drilling (HDD) is investigated in this paper. Convergences and divergences between the measurement techniques are presented.

Data available from different strain technologies mounted on ILI tools offers an opportunity to conduct a comparative study and to provide a better understanding of a pipeline’s strain condition. This paper will present the framework for understanding the different strain measurement technologies and an investigation into the pipeline prior strain history (effects from fabrication, hydrostatic testing and external loads) and their corresponding impact on the material state at the time of inspection.
Effect of Notch Type in Drop-Weight Tear Test Specimen on Crack Propagation and Arrest Behavior
Authors: Igi Satoshi , Amano Toshihiko , Sakimoto Takahiro , Shinohara Yasuhiro , Tagawa Tetsuya
Published: November 2018

The drop-weight tear test (DWTT) has been widely used to evaluate the resistance of linepipe steels against brittle fracture propagation. However, in the recent years there is an ambiguity in its evaluation if inverse fracture appears on the specimen fracture surfaces. Although cause of the inverse fracture is not fully understood, compressive pre-straining near the impact hammer and existing tiny split have been discussed as a possible cause.

In this paper, machined notch in brittle weld DWTT for X65 was performed and compared with various notch types of DWTTs such as conventional DWTT specimen with a pressed notch (PN), a chevron notch (CN) and a static pre-cracked (SPC). The fracture appearances were compared with different strength X65 - X80 grades linepipes and with different initial notch types. The frequency of the inverse fracture appeared in these DWTTs were different in each material and each specimen types, but there were no cases where the inverse fracture did not occurs.

The purpose of DWTT is to evaluate the brittle crack arrestability of the material in a pressurized linepipe. A large scale brittle crack arrest test, so called West Jeferson test is generally used to reproduce crack propagation and arrest behavior in an actual pipeline material. A middle scale test so called Crack Arrest Temperature (CAT) test was also proposed to check the shear area fraction measured in DWTT with API rating with that the local shear lip thickness fraction in those tests. CAT test can well reproduce crack propagation and arrest behavior under the condition of brittle crack initiation from the initial notch.
How Dry Is Dry?
Authors: Hartloper C. , Botros K. K. , Liu V. , Lalonde G. , Lu J. , Saud de Puche Y.
Published: November 2018

Air drying is used after dewatering to dry a pipeline or piping facility before commissioning it with natural gas. This process typically involves blowing dehydrated air through the pipe sections until they are determined to be suitably dry. The question addressed in this paper is: how dry is dry? A common metric used to judge the pipe section’s dryness is the drying air’s outlet water dew point. Typically, air drying continues until a suitably dry low water dew point, such as −40°C, is measured at the outlet of the pipeline or facility. However, there is currently a lack of understanding of how this final outlet water dew point relates to the remaining water and thus the subsequent start up of the pipeline or facility. If the outlet water dew point is higher than required, issues may arise upon start up; e.g., hydrates could form along the pipeline or at downstream facilities. Conversely, if the outlet water dew point is lower than required, unnecessary time would have been spent in drying, and hence higher cost.

This paper advocates an approach to determine when air drying is complete that considers the start-up phase. The approach consists of two parts. In the first part, the air drying parameters (drying air flow rate, inlet water dew point, etc.) and the final outlet water dew point are used to quantify the volume and surface area of water remaining after the drying process is completed. In the second part, the evaporation of this water into the gas flowing through the pipeline/facility after commissioning and start up is modeled as a function of the gas flow rate, temperature, pressure and inlet water content. Then, the water content of the gas at the delivery points is calculated. This increase can then be evaluated in reference to the water content specifications at the delivery points. The approach is exemplified by a 31 km NPS 48 pipeline over a mountainous terrain.
A Brazilian Pipeline Incident Database: The PETROBRAS and TRANSPETRO Initiative
Authors: Alves Douglas , Bahiense Ana , Bastos Michelle , Borges Cassiano , Lima Gilson
Published: November 2018

Statistical data available from several international sources, such as the reports provided by the European institutions EGIG, CONCAWE and UKOPA, as well as by the American Department of Transportation – DOT, indicate that pipelines represent the safest mode of transportation for hydrocarbons and other dangerous products when compared to other alternatives, such as road, rail, waterway, etc. Operators ensure a high level of safety of their pipelines by investing large amounts of effort and resources in accident prevention, efficient contingency procedures, environmental protection and reliability along the life cycle of their assets.

However, the pipeline industry, both in Brazil and abroad, is frequently asked to demonstrate their safety performance both by environmental and regulatory agencies, as well as by society, considering the assets already in operation and also those that will still be built (new pipelines). Such requests are based on the most opened and detailed communication between pipeline operators and the other stakeholders involved.

In this context, the organized and standardized collection of data related to pipeline failure events, such as failure mechanisms and their consequences, along with relevant and specific data regarding the assets and their operations, is essential to foster the process of knowledge construction on this topic. It allows generating consistent information both to meet the stakeholders’ requests and to improve risk management of pipelines by the operators, ultimately supporting decision-making.

Therefore, this work aims to create a Brazilian Pipeline Incident Database, considering firstly gas pipelines and oil pipelines operated by TRANSPETRO, a PETROBRAS Subsidiary. This research intends to study the characteristics, the architectures, the assumptions and the principles adopted by the international pipeline failure databases currently available, considered here as benchmarks, in order to propose an analogous and specific structure for the reality of the Brazilian Pipeline System.
Simulating In-Service Welding of Hot-Tap Branches to Quantify the Effect of Geometry on Level of Restraint
Authors: Dyck Jason , Guest Stuart , Kohandehghan Alireza , Lepine Sean
Published: November 2018

Economic and environmental incentives encourage operators to maintain pipeline operation during repair and maintenance procedures including hot-tap branch fitting installation onto pipelines. Welding onto a liquid-filled pipeline induces accelerated cooling of the weld and heat affected zone (HAZ), increasing the propensity for cracking. In-service welding codes and due diligence requires that several key factors be considered during the design of an in-service welding procedure specification for its intended purpose. The level of restraint (LoR) imposed by the geometry, material, or dimensional differences of the branch compared to the run pipe has also been shown to be a significant contributor to cracking. Finite element analysis (FEA) was utilized to investigate the geometric effects of an in-service weld procedure to approximate the LoR of hot-tap branch installation. The LoR was quantified and compared by simulating multi-pass weld sequences on two configurations: a branch-on-pipe (BoP) configuration of various dimensions and a configuration using perpendicular plates (PP) that has been used as an alternative to the branch-on-pipe configuration. The highest LoR, as measured by transverse tensile stress at the fillet weld toe, was the branch-on-pipe configuration with the largest branch wall thickness, the smallest branch diameter, the largest run pipe diameter, and the largest run pipe wall thickness. FEA modeling revealed that the PP configuration has lower LoR, thus it is not recommended to use for simulating in-service branch weld procedures.