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Pipeline Technology Journal - 4/2024 This Issue’s COMPLETE CONTENT 12 Guidelines for Standardised Evaluation Procedure for Corrosion Protection Materials T. Kaiser, Dr. T. Löffler, M. Torkler 20 AIoT-Driven Deadleg Corrosion Monitoring: Future-Ready Asset Integrity Management V. Eswara, S. Schieke 26 Using Data Analytics to Unearth the Relationship Between Geohazards and Pipeline Corrosion J. Walker, E. Bennett, J. Martin, J. Soltis  Pipeline Technology Journal - ptj  www.pipeline-journal.net # #pipelinejournal

6 Pipeline Technology Journal - 4/2024 Chairman Dr. Michael Beller Director, Global Market Strategy ROSEN Europe Members Editorial Board Adrian Lim Global Management Consultant INTECSEA Ana Nunez Anton EU Chemicals Pipeline Manager Shell Asle Venas Director Charge Energy AS Prof. Dr. Jürgen Schmidt Excecutive Director CSE Center of Safety Excellence Dr. Khalid A. Al-Jabr Reliability Engineering Specialist Saudi Aramco Mahmoud A. Hakim Head of Discipline Pipeline Engineering ADNOC Group Dr. Marion Erdelen-Peppler Secretary General EPRG Max Wedekind Managing Director DENSO Group Germany Dr. Mike Kirkwood Director, Integrity Engineering Solutions T.D. Williamson Mohd Nazmi bin Mohd Ali Napiah Custodian/Head/Group Technical Authority PETRONAS Steffen Paeper Independent Pipeline Professional www.pipeline-journal.net ptj@eitep.de puBlishEr EITEP, Euro Institute for Information and Technology Transfer GmbH Marie-Jahn-Straße 20 30177 Hannover, Germany Tel: +49 511 90992-10 URL: www.eitep.de issn e-ISSN: 2196-4300 p-ISSN: 2751-1189 Copyright MatErial P 1 © Steffen Weinrich P. 8-9 © Shutterstock/ Lifestyle Travel Photo Managing Board Dennis Fandrich & Marian Ritter Register Court: Amtsgericht Hannover Company Registration Number: HRB 56648 Value Added Tax Identification Number: DE 182833034 Editor in ChiEf Dennis Fandrich E-Mail: d.fandrich@eitep.de Tel: +49 511 90992-22 tErMs of puBliCation Four times a year Editorial ManagEMEnt Marian Ritter E-Mail: m.ritter@eitep.de Tel: +49 511 90992-15 Constantin Schreiber E-Mail: c.schreiber@eitep.de Tel: +49 511 90992-20 Editorial staff Mark Iden Daniel Onyango advErtising Timo Eßer E-Mail: t.esser@eitep.de Tel: +49 51190992-99

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12 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY Guidelines for Standardised Evaluation Procedure for Corrosion Protection Materials T. Kaiser1, Dr. T. LöFFler1, M. Torkler2 > 1DENSO Group Germany, 2 Solventum Abstract The requirements for pipeline construction and corrosion protection are becoming increasingly demanding. For modern construction with sustainable protection, selecting the right materials is both crucial and challenging. Although compliance with product-specific regulations is often seen as a guarantee for the universal suitability of products, it is nevertheless limited. On the one hand, the mere achievement of com- pliance with standards (like ISO or EN) may be too low to confirm suit- ability for a specific pipeline design or construction. On the other hand, products are already available today that far exceed the requirements of these international leading standards. The mere fulfilment of the re- spective standards is therefore only of limited importance. It should in- itially be understood as proof of quality. In addition, a product should fulfil the real and project-specific requirements of a pipeline. For the first time the German Technical and Scientific Association for Gas and Water Sectors (DVGW), as an internationally recognised in- dustry association, has created a guideline for this issue in its Code of Practice GW 32. The use of this code facilitates the evaluation of cor- rosion protection products for buried steel pipelines by defining the “real” necessary technical requirements for the construction. The in- troduction of these construction categories marks a significant ad- vance in efficiency, quality and user-friendliness in the selection and classification of the right corrosion protection materials. The code improves the comparability of products and increases the accuracy of the selection, thus ensuring the durability of corrosion protection.

14 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY The task for engineers, planners and pipe network op- erators of maintaining an overview is made even more difficult by the fact that a range of properties are char- acterised by the project-specific combination of many different requirements. Figure 1 illustrates the extent to which such conditions can vary for a pipeline con- struction project in Germany. Fulfilment of standards like ISO and EN is therefore only a necessary condition – like an entry-ticket to the event – which in a first step narrows down the num- ber of possible solutions in line with a basic quality re- quirement. Due to its limited informative value regard- ing the diversity of the specific project requirements, it should not be used alone for an assessment of suita- bility. The assessment can only be made after the con- struction-specific requirements have been compared with the tested range of properties of the intended solution. This performance-proof for the present ap- plication is crucial and replaces the previously labori- ous individual assessments. 3. Construction categories for standardised selection For the first time, the German Association for Gas and Water (DVGW) is presenting a guideline for a stand- ardised selection. As an internationally recognised in- dustry association, the DVGW is responsible for cre- ating technical rules and standards for testing and certification, and promotes technical innovations for a safe gas and water supply. The DVGW also sets in- ternational standards in its Gas & Water GW 32 Code of Practice. For the first time, the DVGW created a sys- tematic and practical guide for the reliable assessment of corrosion protection products in terms of their me- chanical strength. With the help of this new bulletin, the classification and selection of corrosion protec- tion materials for buried pipelines is achieved by as- signing them to the real technical requirements of the construction and pipeline design. The introduction of these construction categories marks a significant ad- vance in efficiency, quality and user-friendliness in the selection process. The Code of Practice improves the comparability of products and increases the speed and accuracy of selection for the application of the most suitable solutions – and thus serves the durability of corrosion protection. The Code of Practice GW 32 takes a two-pronged ap- proach: First, it explains construction-related re- quirements and how they relate to the property tests (characteristic values) of field-applied coatings. The re- lationships are clearly described, making it easy to un- derstand them. In the second step, the properties are evaluated in terms of their significance and classified ac- cordingly into: a. ‘Universal’ properties, which should be fulfilled in a construction-independent manner in accord- ance with the standards (e.g. cathodic disbond- ing). For these characteristics, compliance with the standards like ISO or EN is a sufficient criterion. b. Other ‘core’ properties, which, depending on the construction, are subject to special requirements that deviate from the applied specifications of stand- ards like ISO and EN and are generally more stringent. The structure follows that of DIN EN 12068. This in- ternationally recognised standard has always dis- tinguished between three different mechanical load classes, labelled A, B and C. This standard was set up a long time ago and is now only valid for a few solutions. In addition, the limit values of the key figures have re- mained unchanged for decades. The end user standards of various companies also fol- low this approach to varying degrees, for example by considering the type of structure/design (transport pipeline or station construction), the type of construc- tion (in a trench or trenchless) or the type of bedding (sand or rock). This is how individual products are ap- proved or the product properties are specified with minimum requirements depending on the application. However, the findings and company-specific require- ments, which are mostly based on experience, are nei- ther independent nor accessible to the public. A basis that is reliable and comprehensible for everyone re- quires a standardised, generally available structure. The construction categories of GW 32 provide such a structure by offering a reliable and comparable basis for selection. For the first time, this new Code of Practice presents a standardised evaluation procedure that goes beyond the mere “ticket” of standard conformity and the well-known classifications of DIN EN 12068. In doing so, various real-life project conditions and challenges (e.g.

16 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY Figure 2: General overview of the construction categories with the respective requirement values. without a specified value is not found in category F, as it does not meet the requirements of the assigned struc- tures. The description of the assignment from the table clarifies the wording: ‘Soil conditions and boundary con- ditions extremely demanding’, such as ‘large grain size, heavy traffic loads and movements, temperature fluctu- ations, backfill material from excavation or excavation material processed with a “breaker” (source: DVGW GW 32, note from table header B.1, category F).

18 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY 6. Guidelines for engineering offices and operators for a standardised selection The introduction of the construction categories ena- bles a clear and standardised classification of corro- sion protection products. It steers the line of vision away from the product classification according to the performance of a product design only within a selected product group and towards the consideration of the actually required product performance related to the project and construction specific requirements. Considering the specific requirements of the indi- vidual pipeline construction ensure the selection of a suitable solution that will lead to significantly in- creased efficiency and reliability in practice. Thanks to the standardised procedure, not only will the plan- ning and tendering phases of construction projects be more targeted, but the safety and durability of infra- structures in a wide range of applications will also be improved in the long term. Product selection is based on a two-stage system con- sisting of a) the “entry ticket”, i.e. fulfilment of the standard, and b) the “proof of performance”, i.e. ful- filment of the requirements of the construction cate- gory. Product suppliers only have to confirm conform- ity with the requirements of individual construction categories. In tenders for pipeline construction pro- jects, fulfilment of a relevant standard (e.g. DIN 30672- 1, DIN EN 12068, DIN EN ISO 21809-3) is still required to ensure a minimum standard – the “entry ticket”. The conformity requirement for a construction category is used to tailor the requirements and demands of the re- spective construction project. To do this, the engineer and operator assigns the construction or a single section of the construction to a category. It remains the planner's responsibility to check whether conformity with the cat- egory alone is sufficient to assess usability. In individual cases, there may be further project-specific requirements. The GW 32 Code of Practice is a very useful guide to understanding the requirements and at the same time simplifying the process. The adapted procedure, with the use of construction categories, ensures a high de- gree of transparency in the planning, tendering and evaluation of field-applied coating materials. Furthermore, the continuous development and adap- tation of the construction categories to new require- ments and technologies ensures that the industry will continue to meet the challenges of a dynamic market in the future and that high-quality solutions for tomor- row's infrastructure projects will be possible. AuthorS Dipl.-Ing. Thomas Kaiser DENSO Group Germany Managing Director thomas.kaiser@denso-group.com Dr. Thomas Löffler DENSO Group Germany Head of Competence Center Corrosion Prevention thomas.loeffler@denso-group.com Max Torkler, MSc Solventum Senior Sales Representative Biopharma mtorkler@solventum.com

20 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY AIoT-Driven Deadleg Corrosion Monitoring: Future-Ready Asset Integrity Management V. Eswara, S. Schieke > mPACT2WO, a Molex Business Abstract Efficient hydrocarbon transportation depends on extensive pipe- line networks requiring regular inspections for safety and effi- ciency. Deadlegs, parts of the system prone to corrosion, pose significant challenges. Traditional manual ultrasonic test- ing lacks the accuracy needed for effective corrosion assess- ment. Permanently installed ultrasonic sensors, enhanced with Artificial Intelligence of Things (AIoT) and NDE 4.0, provide a better solution. These technologies use non-destructive methods and digital tools, like AI and machine learning, to detect mate- rial flaws, offering higher quality and more frequent data. A case study demonstrates how advanced AIoT solutions effectively monitor deadlegs, ensuring pipeline integrity. Implementing these technologies enhances corrosion detection and mitigation, safeguarding critical infrastructure.

22 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY Figure 2: Impact of Corroding Surfaces on Ultrasonic Waveforms and Thickness Measurements Figure 3: Misleading Thickness Increase Due to Active Corrosion

24 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY Figure 5: Circuit-Level Visualization of CML Status Machine learning can contextualize data from numer- ous Condition Monitoring Locations (CMLs). Figure 5 illustrates a circuit-level dashboard displaying sen- sor locations on an ISO diagram, with colors indicating CML status relative to thresholds—red signals a breach. Event and list widgets provide circuit overviews, and linked dashboards enable seamless navigation be- tween detailed analyses and circuit-level views. 3. Proven Customer Deployment One of the largest oil and gas companies has trans- formed its corrosion monitoring by implementing mPACT2WO’s mCluezTM Corrosion Monitoring solu- tion. This advanced technology has significantly en- hanced the monitoring of hundreds of CMLs on dead- legs, including those with piping diameters as small as two inches. The AIoT solution, that uses sensors to deliver precise, real-time insights,has been instrumental in accurately identifying long-term corrosion rates, with some CMLs exhibiting rates as high as 15 mils per year. Figure 6 il- lustrates the thickness trend for a CML on a deadleg within the facility. The high data quality visible in the A-Scan ensures that the thickness trend and the cor- rosion rate of 15 mils per year were determined with high confidence. This precise determination starkly contrasts with surrounding CMLs, which show corro- sion rates not exceeding 3 mils per year. This case study underscores the effectiveness of this advanced technology in providing reliable, high-qual- ity data, enabling the company to maintain pipeline integrity and prevent costly failures. 4. Summary Internal corrosion of deadlegs in pipeline facilities is a leading cause of failures. Industry standards such as API 570 recommend closely monitoring deadlegs when their elimination isn't feasible. Permanently

26 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY Using Data Analytics to Unearth the Relationship Between Geohazards and Pipeline Corrosion J. Walker, E. Bennett, J. Martin, J. Soltis > ROSEN Group Abstract Prediction of external corrosion using data from in-line inspections (ILI) can be instrumental in making proactive pipeline integrity management decisions, especially when integrated with geospatial data. This work investigates how a relationship may be established between the presence of bending-strain areas and the initiation and or progression of external corrosion. As the initiation of external corrosion requires both failure of the external coating and failure of the cathodic protection system, it may be possible to limit the dam- age caused in areas of bending strain by adopting inspection and repair strategies reflecting the pipeline integrity risks. The study examines how integrating geohazard characteristics into machine learning models improves the prediction of external corrosion. The paper provides insights into the complex interplay of geohazards, bending strain, and corrosion, informing better integrity manage- ment strategies. This study suggests that a shift towards a holistic, automated, machine learning-assisted approach for pipeline integ- rity can be attained in compliance with regulation and highlights the importance of data-driven approaches for safety and reliability.

28 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY understanding of defect risk factors by understanding the relationship between geo-enrichment variables and known pipeline sections that contain defects (or sections without defects). We have introduced the fol- lowing datasets into the IDW: • Geology: Geological period and mineral composi- tion [4] • Soil: Type, material content, moisture and pH [5] [6] • Groundwater: Depth and distance to the nearest water table [7] Figure 1: Example RADAR DEM represented by the greyscale colour mapping [7]. • Precipitation: Hourly precipitation data [8] • Elevation: Digital elevation maps (DEM) con- structed from RADAR and LIDAR point cloud data from the 3DEP project [9] [10] [7] • Terrain Classification: Clustering of terrain into discrete definitions [11] [12] • Historical Landslide data: Distance and duration since nearby landslides [13] [14] [15] • Land use classification: Clustering of land use into discrete definitions [16] • Open Street Maps: Intersections with roads, rail- ways, or waterways [17] In some cases, these datasets are pre-processed or ag- gregated in a bespoke manner. For example, the pre- cipitation data is aggregated into percentiles over monthly periods, and LIDAR DEM tiles are processed at a resolution of 1m from point cloud data. These data- sets are available to query for any combination of lati- tude and longitude locations, not just those directly on the pipeline route. This flexibility allows us to collate information on surrounding points of interest within a given proximity to pipelines. 3. Slope Units We consider a subset of pipelines within the IDW for which we have inspection data sensitive to both exter- nal corrosion and bending strain defect features. In Figure 2: Example Terrain22 classification of continental North America with each color representing a unique terrain type [11] [12]. particular, we consider a region of size 150,000km² within the states of Ohio, West Virgina and Pennsylvania, USA. This region is an insightful study region as it con- tains pipelines within the Appalachian Mountains and the Interior Lowlands, providing a diverse geography within the dataset. Slope units are segmented regions of terrain partitioned by drainage and divide lines. They provide a natural landscape clustering as they inherently incorporate terrain geometry in their structure, making them powerful tools for geohazard risk assessment. A typical slope unit has a length scale of ~100m, which is a suitable scale for capturing meaningful aggregation of geospatial features. Thus, they are a powerful component in calculating geohazard risks at scale [18]. 3.1 SUMak algorithm Slope units are expensive to compute; however, with careful selection of regions of interest and pragmatic use of resolution scales, their calculation can be per- formed efficiently. In this work, we have rewritten and deployed a bespoke version of the Slope Unit Maker

30 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY Figure 4: Histogram of the slope angle of slope units over all regions aggregated over region type. An additional histogram Unaggregated Average is the average slope angle of all slope units that exist within the IDW to date. Error bars represent the standard error across each bin over all regions of each category. external corrosion and bending strain regions contain slope units with higher degrees of slope angle than control regions. We also average over all 20,000 cal- culated slope units contained within the IDW and see that the control regions have a higher proportion of a slope angle less than 2.5 degrees than this unaggre- gated average, indicating that the slope angle is a po- tentially good indicator of risk to defect feature types. 4. External Corrosion Prediction In this section, we take a high-level approach by produc- ing machine learning (ML) architectures, which might be used to predict external corrosion or high-risk areas. We construct an ILI inspection dataset enriched with the geospatial features as defined in section 2. This da- taset comprises joint level inspection data of over 5500 ILI inspections across the USA, and we aggregate geo- spatial features to the joint level; this means that the ge- ospatial properties surrounding each joint are averaged in some manner. For this study, we define two predictive classes for the model: the positive class (P), for which ex- ternal corrosion anomalies are present at the joint level to greater than 10% of wall thickness, and a negative class (N), where external corrosion anomalies are not present to this extent. We chose 10% as the threshold, the typical reporting depth from many ILI tools. We consider data within the USA for two reasons. First, we guarantee consistent infrastructure legisla- tion within the dataset and high-quality inspection data. Second, the availability and quality of the geo-en- richment features are of a high standard by exploit- ing the plethora of USA government surveys and data sources. The first point is important as we eliminate the possibility of spurious predictive power from the ML models which might be introduced from external variables not directly represented in the dataset but to which they are indirectly sensitive. We perform a typical set of ML data preparation prac- tices. The numerical data is normalized, and categor- ical data is one hot encoded. By standardizing in this way, we ensure that any one machine learning model is initially as sensitive to any one specific feature as any other, removing potential biases and improving model stability. We train two XGBoost [21] models, one with pipeline features only and one with geo-enrichment features with a randomized 90% train and a 10% test split. For XGBoost, we may choose a set of model hy- perparameters that precisely control the training and model behavior; we select the best parameters by per- forming a hyperparameter grid search, which explores the full parameter space and picks the best combina- tion based on our chosen validation metric. XGBoost is an efficient and powerful architecture that combines a series of weak classifiers, producing powerful and more accurate predictions when collated. The result- ant dataset is highly imbalanced, due to most pipeline joints being in the negative class, comprising 90% of the data. Thus, it is essential to consider other metrics than accuracy; in our case, we take the balanced accu- racy as a predictive metric of the model, but we also consider additional metrics such as f1 score, precision, recall, and area under the precision-recall curve. 4.1 Transparent Machine Learning To dissect the model input features and their relevant importance, we use SHapley Additive exPlanations (SHAP) values [22]. SHAP values provide a way to glean

32 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY limited by the quantity of bending strain data; as more data is added to the IDW, there will be opportunities for deeper studies and the use of ML tools for which slope units could also be used directly as inputs. Slope units provide a natural basis for evaluating pipeline risk and generating natural aggregations of geospatial fea- tures, reinforcing geospatial relationships in the data. Additionally, new risk factors may be exposed by con- sidering the spatial relationship between slope units and the sections of pipeline they contain; for example, the pipeline trajectory through a slope unit has not been considered here. There is also an opportunity to utilize an increased level of detail of the bending strain data, where more insight might be possible by considering strain measurements along the length of the pipeline, not just for sections above the reporting threshold. Early results using ML models demonstrate clear clas- sifying power for external corrosion predictions from IDW data, although there is significant room for im- provement. Currently, there is a significant aggrega- tion of the data, which limits any architecture’s predic- tive power. Each data point is at the joint level, which means that the severity of external corrosion across any joint area with an anomaly of at least 10% wall thickness is all lumped together in the positive predic- tive class. Further, some joints may run over regions of terrain with changing features that get aggregated away. Future models will reconsider this approach; re- gions of the pipeline will be segmented at fixed lengths and fixed geospatial features. Despite these shortcom- ings, using SHAP values to assess feature importance, we discover that geo-enrichment feature inputs have comparable feature importance to pipeline property features when included in XGBoost models. In response to the increasing challenge of geohazards driven by climate change, our research demonstrates the importance of analyzing and assessing combined integrity threats and coincident anomalies, indicat- ing how ML techniques can be utilized to understand them. The work presented in this paper demonstrates the complex challenges of modeling external corro- sion from ILI inspection data. The developed models show predictive power despite naïve approaches to data aggregation, and future work will aim to improve this methodology to fully exploit a range of geospatial features and develop more powerful predictive models. Figure 7: The geo-enriched model confusion matrix. Where P represents the positive class, external corrosion greater than 10% depth of wall thickness and N the negative class, less than 10% depth. cost perspective, precision is more appropriate as we wish to minimize false positives such that erroneous recommendations for pipeline inspection are reduced. When developed further, models like this could be used as a decision support tool to advise engineers of regions of high risk, not provide precision predictions. Further model validation and data engineering are re- quired. Ongoing work is being performed to improve data aggregation methodology and the models capa- bility to learn and make more meaningful predictions. Currently, the data aggregation and methodology are naïve; by predicting corrosion depth alone with a spe- cific cut-off, we could omit shallow but large corrosion areas or clustering of defects. This methodology also makes assumptions on the aggregation of geospatial features; complex terrain details may be averaged out, which otherwise would be very powerful predictive features for our ML models. Slope units will provide a more natural way to aggregate geospatial features, and we have demonstrated that they may be used as a basis for predictive geohazard models. The input data dimensionality should also be reduced, features with low feature importance should be removed and approaches such as Principal Component Analysis can reduce model complexity while retaining predictive power. Despite these short comings, these models illude to great potential in the dataset. We have gained insight into the most critical features and the validity of includ- ing expanded geospatial features in such models. 5. Outlook and Conclusions This study demonstrates a relationship between slope units and their features and known areas of exter- nal corrosion or bending strain. However, this work is

34 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY Subsea Pipeline Repair Readiness Approach for Efficient Underwater Repairs Q. Saleem, R. Al-Shiban, S. Al-Nutifat > Saudi Aramco Abstract Subsea pipelines, such as in-field flowlines, trunklines, etc., are an integral part of all offshore field developments. Pipeline damage can occur either dur- ing construction phase or during the life of field. Critical pipeline damage such as leak, rupture, or crack requires repair to be performed on an emer- gency basis. Repair readiness is being prepared to respond quickly and effec- tively in the event of a major incident resulting in loss of containment. The primary purpose of repair readiness is to ensure that an emergency repair can be carried out in a timely manner, thereby minimizing the consequences of failure and reducing pipeline downtime. This paper discusses the main ele- ments of the subsea pipeline repair readiness plan, each of its elements will help improve the ability to carry out an emergency pipeline repair. Repair readiness approach will ensure that emergency pipeline repair can be per- formed efficiently and with minimum impact on production.

36 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY The maintenance contracts with third party contrac- tors, as required, should be in place. Maintenance contracts may be required, e.g., for vessels and hyper- baric welding. The contracts should clearly state the responsibilities of the contractor, and should meet all Company requirements for a given repair method. A well-defined contracting strategy should be developed for each repair type and the associated repair steps. The roles and responsibilities should be clearly defined to cover all aspects of emergency pipeline repair. The per- sonnel involved should be familiar with pipeline repair methods, Company procedures, parts and equipment, and should be suitably trained and qualified. This will ensure that all activities are carried out in a safe manner. A repair readiness workshop should be conducted on a regular basis with personnel from engineering, op- erations, inspection, and maintenance. The workshop should capture the full range of activities associated with returning the pipeline to service after failure. Subsea pipeline repair readiness plan should be re- viewed on a regular basis to ensure that it is meeting its objective. The changes to the pipeline system, e.g., new pipelines should be correctly identified and the relevant procedures and spares should be updated. Periodic auditing of the emergency response capabil- ity of the contractor should be performed. Implementation of various elements of the subsea pipeline repair readiness plan, as outlined above, is vital to its effectiveness. 3. Subsea Pipeline Repair Methods Bolted clamps are most widely used for carrying out the permanent repair of subsea pipelines (Figure 1). Offshore bolted clamps can be used for severe inter- nal corrosion defects, leaks, and for externally dam- aged pipeline, due to external corrosion or mechani- cal damage, such as dents. Figure 1: Bolted clamp installed on a subsea pipeline due to internal corrosion anomaly The suitability of a bolted clamp for a given applica- tion should be assured by considering all of the relevant Figure 2: Mechanical connector installed on a subsea pipeline end

38 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY The selection of most suitable repair method/s for a given application depends on several factors. For ex- ample, for subsea pipelines operating at high pres- sure & high temperature, composite repair may not be a suitable repair method which is most suited for low pressure pipelines. Furthermore, the use of hyper- baric dry welding is very limited due to extremely high cost associated with this repair method. 4. Conclusions Critical pipeline damage such as leaks, ruptures, or cracks require repair to be performed on an emergency basis. Repair readiness is being prepared to respond quickly and effectively in the event of a major incident resulting in loss of containment. A comprehensive pipeline repair readiness plan will help to carry out an emergency repair in a timely manner. Implementation of the plan’s various elements is vital to its effective- ness. The repair readiness approach will ensure that emergency pipeline repair can be performed effi- ciently, and with minimal impact on production. 5. Acknowledgement The authors would like to thank Saudi Aramco Management for permission to publish this paper. References 1. Vanaei H.R., Eslami A. and Egbewande A., “A Review on Pipeline Corrosion, In-Line Inspection (ILI), and Corrosion Growth Rate Models,” International Journal of Pressure Vessels and Piping, 2017. 2. The DNV-RP-F116 – Integrity Management of Submarine Pipeline Systems, 2015. 3. Koto J. and Putrawidjaja M., “Subsea Pipeline Damaged in Balikpapan Bay Caused by Anchor Load,” Journal of Subsea and Offshore-Science and Engineering, 2018. 4. Tawekal R. L., Rante Allo R. P. and Taufik A., “Damage Analysis of Subsea Pipeline Due to Anchor Drag,” International Journal of Applied Engineering Research, 2017. 5. Al-Abbas F. M., Muaili S., Saleem Q., Bakthavatchalu B., Haque E. and Barout M., “Corrosion Risk Assessment Model Of Subsea Pipelines Network,” Corrosion 2018, NACE International, 2018. 6. Al-Abbas F. M., Saleem Q. and Harb A., “Top of Line Corrosion Probabilistic Risk Analysis for Wet Sour Subsea Pipeline,” Corrosion 2019, NACE International, 2019. 7. Al-Shiban R. and Al-Nutifat S., “Mechanical Systems for Offshore Pipeline Repair in Saudi Aramco: A Case Study,” Pipeline Operations & Management – Middle East, 2016. 8. Berge J. O., Armstrong M. and Woodward N., “Welding Robot Repairing Subsea Pipelines,” Offshore Technology Conference, 2015. 9. Fostervoll H., Aune R., Berge J. O. and Woodward N., “Remotely Controlled Hyperbaric Welding of Subsea Pipelines,” 6th Pipeline Technology Conference, 2011. 10. d’Auria, S.B., Slimani, H., Wiet, P., Gaffard, V. and Popineau, D., “Subsea Pipeline Repair by Composite System: One Step Deeper,” OTC 24052, Offshore Technology Conference, 2013. 11. Liew, S.C. and Green, M.A., “Testing and History of Composite Repair Systems for Subsea Pipeline Repair,” OTC- 26373-MS, Offshore Technology Conference, 2016. 12. Kulkarni, S. and Alexander, “An Operator’s Perspective in Evaluating Composite Repairs,” IPC2010-31595, Proceedings of 8th International Pipeline Conference, 2010. 13. Napiah, M.M. and Ling, K. S., “Innovative Repair Solutions for Pipeline and Riser,” OTC-25040-MS, Offshore Technology Conference, 2014. 14. Popineau, D., Wiet, P. and d’Auria, S.B., “Subsea Pipeline Repair by Composite System,” SPE 162509, Society of Petroleum Engineers, 2012. AuthorS Qasim Saleem Saudi Aramco Engineering Consultant qasim.saleem@aramco.com Riyadh Al-Shiban Saudi Aramco Engineering Consultant riyadh.shiban@aramco.com Shadid Al-Nutifat Saudi Aramco Senior Engineer shadid.nutifat@aramco.com

40 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY In-Service Welding onto Thin-Wall Pipelines using an Austenitic Electrode as a First Buttering Layer Dr. O. BOULEDROUA > SONATRACH Abstract The hydrocarbon transportation and distribution industry benefits greatly from in-service welding by reducing operational disruption costs. In-service welding is used to repair internal and external de- fects, such as leaks, using weld deposition or sleeves (Type A or B) and hot tapping operations. If in-service welding is not possible, then sec- tions of a pipeline have to be sealed and degassed prior to welding, and then re-purged prior to reinstatement. Since there are high gas losses and methane is a greenhouse gas, these are costly, wasteful, and envi- ronmentally destructive practices. TransCanada Pipelines Ltd. has es- timated that, relative to a cold connection, a hot-tap avoids gross rev- enue losses of approximately 1 M$ Canadian per hot-tap. The main objective of this work is to provide an in-service welding procedure that allows operators to operate under more severe condi- tions (in terms of flow rate and pressure) and at thinner thicknesses than the minimum thickness recommended in the standards, while minimizing the risk of burn-through and hydrogen embrittlement.

42 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY coefficient of thermal expansion of nickel alloys com- pared to stainless steel, nickel alloy electrodes are often preferred to minimize shrinkage strain in highly restrained joints [19]. In this project, the austenitic electrode E309LMo is utilized as the first buttering layer in fillet welds. This electrode is characterized by its low current intensity, which results in a lower heat input (see Eq. (1)). The use of austenitic electrodes allows us to avoid the phenomena of collapse, lamellar tearing, and hydro- gen embrittlement. 2. Results and discussions 2.1 Electrode’s comparisons In this section of the study, we compare three different welding electrodes: E7018 (diameter = 3.2 mm), E7018 (diameter = 2.5 mm), and E309LMo (diameter = 2.5 mm). This comparison aims to evaluate their perfor- mance in a practical welding application. To facilitate this comparison, three distinct welding beads were deposited onto a pipe with an internal water flow system. This setup allows us to assess the performance of each electrode under conditions that closely mimic real-world applications. Figure 1 (a) and (b) illustrates the three weld deposits created using each of the electrodes at various time intervals. Figure 1 (b) shows that the E309LMo electrode provides better control and produces a more consistent weld bead. The weld made with the E309LMo electrode are notably uniform and smooth, demonstrating its effec- tiveness in maintaining a steady weld pool. This elec- trode's superior control leads to a more regular and aesthetically pleasing bead, which can enhance the overall quality and reliability of the weld. In the Figure 1 (e) (f) et (g), a hardness comparison is presented to evaluate the distribution of hardness across welding beads deposited for the three differ- ent electrodes. To assess the impact of different weld- ing electrodes on the hardness of the welds, a detailed hardness measurement was conducted. This com- parison aims to analyze how each electrode affects the hardness distribution in the weld beads and the Figure 1: Welding beads deposited on a pipe using three different electrodes. (a) test bench, (b) zoom of the Welding beads deposited and (c) cut section.

44 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY In contrast, the E309LMo electrode, with its unique prop- erties, achieved the most favorable results by effectively balancing the risks of burn-through and hydrogen em- brittlement. Its performance underscores its suitability for in-service welding applications field. 2.3 Fillet welding tests The objective of this section was to evaluate the effec- tiveness of using austenitic electrodes for in-service pipeline welding to mitigate the dual risks of burn- through and hydrogen embrittlement. To achieve this, twelve (12) fillet weld tests were conducted under con- trolled conditions. Among these, four (04) fillet welds were specifically designated for testing with austenitic electrodes. To simulate severe operational conditions, the test bench was integrated with the Fire Fighting Water Supply Pipeline System (FFWS), providing a water flow rate close to 1 m/sec. This setup aimed to replicate the thermal and mechanical stresses typically encountered during in-service welding. The process and outcome of longitudinal and fillet welding before and after the application of the sleeve are illustrated in Figure 5. Additionally, Figure 6 depicts an example of a fillet weld produced using an E309LMo austenitic electrode as a buttering layer. This approach allowed for a comparative analysis with fillet welds made using a conventional basic electrode (E7018), as shown in the metallographic sections in Figure 7. Figure 5: Sleeve after and befort longitudinal and fillet welding. Figure 6: The final fillet welding using an austenitic electrode E309LMo buttering layer. Figure 7: Metallographic section of two type of fillet weld bead.

46 Pipeline Technology Journal - 4/2024 RESEARCH • DEVELOPMENT • TECHNOLOGY For companies like SONATRACH, managing extensive pipeline networks, this methodology offers a practical solution for field repairs, reducing operational down- time and environmental impact. The proposed weld- ing procedure specification (WPS) tailored for thin- ner-wall pipelines will serve as a valuable guideline for maintaining the integrity of pipelines in challenging environments. Overall, the findings of this study con- tribute to advancing in-service welding practices, ena- bling safer and more efficient operations in the hydro- carbon transportation industry. 4. Acknowledgments The author expresses sincere gratitude to SONATRACH R&D Central Direction for funding this research and granting permission to publish the results. Special thanks are also extended to all colleagues at SONATRACH-TRC, particularly the Maintenance Division in Laghouat Ex- DML, for providing the essential resources and support necessary to accomplish this R&D project. Special thanks go to Mr. BENARFA Allal, Mr. BENDENNICHE Ahmed, and Mr. BENCHEIKH Abdelkader for their crucial con- tributions and assistance. References Author 1. Bruce, W. A. (2002, January). Qualification of procedu- res for welding onto in-service pipelines. In International Pipeline Conference (Vol. 36207, pp. 39-53). 2. API 1104: 'Welding of pipelines and related facilities'. 3. Wu, Q., Han, T., Wang, Y., Wang, H., Zhang, H., & Gu, S. (2020). In- situ observation of high-temperature failure behavior of pipe- line steel and investigation on burn-through mechanism during in-service welding. Engineering Failure Analysis, 109, 104236. 4. Qian, W., Yong, W., Tao, H., Hongtao, W., Shiwei, G., & Laihui, H. (2019). Study on the failure mechanism of burn- through during in-service welding on gas pipelines. Journal of Pressure Vessel Technology, 141(2), 024501. 5. Da Nóbrega, J. A., Diniz, D. D., Silva, A. A., Maciel, T. M., De Albuquerque, V. H. C., & Tavares, J. M. R. (2016). Numerical evalua- tion of temperature field and residual stresses in an API 5L X80 steel welded joint using the finite element method. Metals, 6(2), 28. 6. Tanaka, T., Yano, T. Y., Katsuki, M., Mayumi, T., Otani, Y., & Oguchi, 7. N. (2017). In-Service Weld Repair Methods for Gas Transmission Pipelines under Public Roads. In Pipelines 2017 (pp. 186-197). Igwemezie, V., Mehmanparast, A., & Ganguly, S. (2024). Assessment of fatigue crack growth resistance of newly deve- loped LTT alloy composition for the repair of high strength steel structures. Journal of Advanced Joining Processes, 100226. 8. Sabapathy, P. N., Wahab, M. A., & Painter, M. J. (2000). The predic- tion of burn-through during in-service welding of gas pipelines. International journal of pressure vessels and piping, 77(11), 669-677. 9. Wang, Y., Wang, L., Di, X., Shi, Y., Bao, X., & Gao, X. (2013). Simulation and analysis of temperature field for in-service multi-pass welding of a sleeve fillet weld. Computational Materials Science, 68, 198-205. 10. Meléndez-Morales, L. D., Ruíz-Mondragón, J. J., & Hernández- Hernández, M. (2023). In-service weld repair by direct deposition: Numerical simulation and experimental validation. Engineering Science and Technology, an International Journal, 46, 101503. 11. Yano, Y., Oguchi, N., Katsuki, M., Mayumi, T., & Ohtani, Y. (2014, September). Development of In-Service Weld Repair Method for L555 (X80)-Grade Pipeline. In International Pipeline Conference (Vol. 46124, p. V003T07A036). American Society of Mechanical Engineers. 12. Bang, I. W., Son, Y. P., Oh, K. H., Kim, Y. P., & Kim, W. S. (2002). Numerical simulation of sleeve repair welding of in-service gas pi- pelines. WELDING JOURNAL-NEW YORK-, 81(12), 273-S. 13. BS EN 1011-2: 'Welding. Recommendations for welding of metal- lic materials. Arc welding of ferritic steels' BSI, London, 2001. 14. Wilson J: 'The development of welding techniques for British fig- hting vehicles.' Proceedings of Trends in Steels and Consumables for Welding, International Conference, London, 13-16 Nov.1978 Paper 2. pp.473-479. Publ. The Welding Institute. 15. Bailey, N: 'Hydrogen cracking and austenitic electrodes' Metal Construction, Vol 10, No. 12. December 1978 pp.580-583. 16. Gooch T G: 'Repair welding [of 'hard to weld' ferritic steels] with aus- tenitic stainless steel MMA [manual metal arc] electrodes.' Metal Construction, vol.12, no.11. November 1980. pp.622-627, 629, 631. 17. Moreton J, Coe F R and Boniszewski T: 'Hydrogen movement in weld metals' Metal Construction, Vol.3 no.6, June 1971, pp. 223-228. 18. Nicholas, T. J. 2010. Development and Qualification of Welding Procedures and Inspection Methodology for In-service Welding. In Evaluation, Rehabilitation and Repair of Pipelines Conference, Berlin, Germany 19. TWI. Defects - hydrogen cracks in steels - prevention and best practice. https://www.twi-global.com/technical-knowledge/job-knowledge/ defects-hydrogen-cracks-in-steels-prevention-and-best-practice-046 Dr. Omar Bouledroua SONATRACH DC-R&D R&D Project Manager omar.bouledroua@sonatrach.dz

48 Pipeline Technology Journal - 4/2024 ptj Young Pipeliner Young Pipeliner Associations are here to stay! The Young Pipeliners Europe recently organized their second Mini Conference in Rotterdam, with a great number and mix- ture of participants. Netherlands, UK, Germany, Belgium, France, Greece and Italy were represented by highly motivated young professionals. The presentations at the mini-conference were all of high level, showed a wide variety of topics and motivated & qualified professionals. The visit to the construction sites of the CO2 and H2 pipelines that are currently being built in the Rotterdam area, also showed a wide interest in the pipeline world – and beyond. We had fascinating discussions about the energy transition, the challenges, the future and the threats & worries about the actual realization. There is no need to elaborate on the incredible amount of work ahead of us – we all know that the pipeline industry is going to play a key-role in the energy transition. And that is why the Young Pipeliners are so im- portant: together with the “old & matured” pipeliners, they will shape the future of the pipeline industry. And we need to facilitate a healthy and appealing working environment to keep this generation connected. “Having opportunities to learn and grow is now the leading factor that defines an exceptional work environment for young employees.” Teamleads, managers en “matured” pipeliners have an essential role in stimulating and facilitating the participation of Young Pipeliners in these events. They need to create the circumstances that enable the youngsters to participate, e.g. provide budget and time. By creating a network of young professionals that know where to find each other, we are preparing this new generation for the challenges ahead of us: a group of professionals that will bring the pipeline industry through the energy transition and guarantee that our assets will safely trans- port energy carriers and feedstocks for the next 30+ years. Don’t miss out on this great opportunity to stimulate the development of your young professionals and make sure to join or support the Young Pipeliners all over the world. Or, as YPPE states it very well: Don’t just be in the industry – be part of it! Sincerely Yours, Cindy Dirkx Independent Pipeline Specialist Dirkx Pipeline Management & Strategy Cindy Dirkx Independent Pipeline Specialist Dirkx Pipeline Management & Strategy

50 Pipeline Technology Journal - 4/2024 ptj Young Pipeliner 1. Introduction A UK gas pipeline operator was required to audit a high-pressure pipeline in line with Clause 12.4.2 of IGEM/TD/1. The standard states that every 4 years, they must affirm the pipeline maximum operating pressure (MOP). To comply, any identified infringements needed further assessment to ensure safe operation at the cur- rent MOP. An aerial survey was conducted to spot de- velopments encroaching on the pipeline, including changes in building proximity, population density, or traffic routes. Additionally, the audit identified popula- tion clusters and sensitive locations situated within four times the building proximity distance (BPD). An initial screening of features was required, followed by a more detailed assessment. This paper reviews and evaluates an example of a risk as- sessment carried out on an onshore gas pipeline, using the quantitative risk assessment (QRA) methodology in line with the U.K standard IGEM/TD/2. 2. Methodology The initial screening includes any infringements that: • Have previously been assessed • Can be screened against an assessed infringement that’ s closer to pipeline with a larger population • Not normally occupied The methodology for QRA for gas pipelines is as follows: I. Failure mode analysis – identify hazards and input pipeline design parameters. II. Frequency analysis - identify failure mechanism and frequency of event occurring. III. Consequence analysis – calculate release rate and determine ignition probability and thermal radia- tion effects. Also ascertain population size. IV. Risk Assessment – quantify the individual and so- cietal risk within the hazard zone. V. Risk reduction – mitigation measures to be imple- mented if risk is not acceptable. 3. Results and Discussion An image of the pipeline and the surrounding popu- lation that was assessed can be seen in Figure 1 below. Anything that falls within the four times the BPD of the pipeline was required to be assessed. Figure 1: Site map of assessment location 3.1 Failure Mode Analysis The pipeline details for the area under assessment can be found in Table 1 below. Table 1: Pipeline details The main hazard identified was thermal radiation re- leased from an ignited full bore rupture on the pipeline that impacts the surrounding population. 3.2 Frequency Analysis The failure frequency is a measure of how many fail- ures are likely to occur on the pipeline over a given time. The most likely failure mechanisms were identified as third-party interference or ground movement, and thus, these factors were used in the analysis. The rupture fre- quency for this pipeline was 1.4338 per million km years. It should be noted that some sections of the pipeline such as road crossings have steel sleeves reducing the likelihood of a failure. 3.3 Consequence Analysis The consequence analysis was carried out by modeling the most hazardous scenario that could affect the sur- rounding population. This was a full bore rupture from 3rd party interference or ground movement where the

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