PPSA Seminar

Magnetic Flux Leakage (MFL) continues to be the most used in-line inspection technology since its widescale introduction in the 1980’s. Thousands of MFL inspections are completed each year by pipeline operators as a reliable and effective assessment method to determine current pipeline condition on which their monitoring, future integrity assessments and repair programs will be based.   Over the years the technology has advanced with combination inspections such as caliper and IMU data gathered efficiently in the same inspection. Advances have also been made in both resolution and the measurement of the three leakage fields that occur in response to corrosion defects. Measurement improvement has benefited detection, characterization and sizing of smaller and more challenging corrosions that otherwise might lead to outliers from specification leading to potential safety risks.   This paper will briefly explain some of the advantages tri-axial measurement has brought to standard MFL analysis, but importantly it will look deeper into how the multiple measurements taken at defects have enabled a step change in the application of AI to improve corrosion measurement sizing accuracy. In addition, this AI capability has introduced the possibility of a defect-by-defect tolerance prediction, and improved corrosion growth estimation. Together, these advances will both reduce conservatism, leading to unnecessary repairs, while at the same time predict where tolerances may be greater and remove unknown risk.   Specifically, the paper will provide insight into the technical development work Baker Hughes has conducted by applying deep learning techniques to large areas of raw MFL data to predict complex defect morphologies and improve burst pressure estimations in situations typically challenging for standard analysis. Additionally, we will discuss how AI is being used to predict new corrosion during run-to-run assessment to consider corrosion cluster growth more accurately as a basis for future integrity assessment.

Lastly, the authors will describe the techniques being adopted to effectively monitor ILI performance to specification, how it is used to identify when inspections may have not met operator expectation and how that data can be monitored to target continuous improvements to system performance.

This case study compares dent strain assessments between ILI and laser scanning methods, showing agreement in overall trends but revealing meaningful variations in measured values. While both techniques produced consistent patterns in strain distribution, the observed differences between methods underscore how inspection approaches can influence results. The research particularly explores scenarios where ASME B31.8 Appendix R shows limitations: with dents approaching 6% restriction, in skewed geometries causing uneven circumferential strain distribution, and in cases where combined high restriction and irregular shape may artificially inflate calculated strains. These findings demonstrate that while the Standard provides a valuable baseline assessment, its assumptions become less reliable for complex dent profiles. The study concludes that supplementary evaluation methods should be considered when dealing with non-uniform dents or those near the Standard's application boundaries, ensuring more accurate strain characterization for integrity management decisions.

Objective, Scope; The repurposing of existing hydrocarbon pipelines for carbon dioxide (CO₂) transportation in Carbon Capture, Utilization, and Storage (CCUS) projects presents both an opportunity and a technical challenge. Ensuring internal cleanliness is critical to safe and efficient CO₂ transport. Traditional cleaning and verification methods offer indirect assurance of cleanliness.

Methods, Process; This paper presents a novel, high-resolution, free-swimming video assessment tool that enables direct visual assessment of pipeline interior conditions. Believed to be the first field deployment of its kind globally, the system captures continuous 360-degree footage of the internal pipe wall over long distances without tethering or real-time data transmission.

Results, Observations, Conclusions; The technology was successfully applied to a 27-KM, 24-inch carbon steel pipeline originally designed for gas service and undergoing conversion for CO₂ transportation. Following a bespoke cleaning programme of brush pigs, foam pigs and batch cleaning fluids to ensure the removal of any pipeline debris the video assessment tool was deployed to verify the pipeline’s readiness. The captured footage provided operators and regulatory stakeholders with unequivocal, quantifiable visual evidence of internal cleanliness, supporting pipeline integrity certification and reducing uncertainty around repurposing decisions.

This paper details the inspection methodology, operational setup, and findings from the case study. It also explores broader implications for CCUS infrastructure readiness and risk management.

Novel/additive information; The technique described in this paper involves the application of the world’s first HD, multi sideview array camera, providing complete pipeline visual coverage. This was combined with a bespoke data analysis and visualisation suite, intuitive and interactive log, creating 2D and 3D models. Critically, it provides all stakeholders with indisputable evidence to allow them to plan and execute pipeline conversion from oil & gas service to transport Co2 without the need for constructing new pipelines.

Preparing gas pipelines for decommissioning or repurposing — especially for future use in Carbon Capture and Storage (CCS) — brings a unique set of technical and operational challenges. This paper outlines the successful cleaning and de-inventorying of two high-pressure gas pipelines: a 24-inch onshore line and a 20-inch offshore line, both of which were previously in sour gas service.

A staged pigging strategy was used to remove residual hydrocarbons, scale, and pyrophoric dust. The operations involved multiple pig runs using a combination of gas and chemistry along with foam pigs. Key focus areas included controlling pig velocity, managing oxygen ingress, and handling the complexities of receiving debris at the terminal end. To reduce the risk of pyrophoric ignition, nitrogen purity was dynamically adjusted during the early phase of each run.

Real-time monitoring of pressure and pig location helped prevent stalls and ensured a safe and controlled process throughout. A final camera inspection confirmed the cleanliness of the pipeline and helped assess its readiness for future use.

This paper shares practical lessons learned from the field, with a focus on operational reliability, safety, and efficiency. It offers a clear, experience-based guide for operators planning similar campaigns in aging pipeline infrastructure.

This paper presents a technical case study involving the internal survey and mapping of a 30-year-old, 4.2km ductile iron pipeline with no available as-built documentation. The project was initiated by a UK utility operator seeking to reinstate the pipeline for operational use. Without drawings or clarity on internal geometry, verifying piggability posed a significant challenge.

A phased, data-driven approach was adopted. Initial feasibility work involved on-site surveys and progressive foam pig trials—first to confirm clearance, followed by a gauging pig and an inertial measurement unit (IMU) to assess internal conditions. Unexpected deformation revealed by a damaged gauge plate prompted the development of a bespoke hybrid pig design, tested and validated off-site in simulated 1D bend conditions.

This paper details the technical methodology, adaptive pig design process, and validation approach, culminating in a successful live survey run that delivered alignment, depth, and obstruction data for the full pipeline. The study highlights a novel application of SMART pigging in uncharted legacy infrastructure, offering valuable lessons in tool adaptability, risk mitigation, and survey execution under uncertain conditions.

This contribution is intended to support pipeline operators and pigging specialists addressing similar challenges in aged assets with limited historical data.

As oil production rates in the North Sea continue to decline operators face increasing difficulty pigging and inspecting major trunklines due to low pipeline velocities. This is a major challenge to pipeline operators, presenting a significant issue with regards to maintaining pipeline cleanliness and collecting data for integrity issues. This paper details a case study whereby working with an inspection vendor to mitigate these issues it was possible to run an inline inspection tool and verify that the regular operational pigging could continue at the nominal low flow rate and significantly below.

Serica, who had a requirement to inspect the 24” main oil line from the Bruce platform, had engaged NDT to provide a UT inspection tool and Jee to provide project management and technical assurance. Inspection of the pipeline had several challenges including low velocity, limited operational windows for tool loading and retrieval, and the requirement for a subsea activation of the tool. In the early stages of the project it was identified that given the low pipeline velocity of insert rate, which was below rates seen in other low velocity pipeline pigging, there was a significant risk of the tool stalling in the pipeline.

To mitigate the risk, pigging trials were undertaken on both the standard operational pig and the inspection tool. The trials successfully proved that the inspection tool could traverse the pipeline without modification at speeds as low as 0.45 mm/s and the operational pig at speeds of 0.2 mm/s, which with minor adjustment, could have improved performance for future declining rates.

With the trials completed and further technical assurance on the ability to pass the pipeline features the inspection was able to be successfully completed and operational pigging verified for continued use in a greater operational window.

This paper presents two internal inspection campaigns involving a tethered robotic crawler system, one for continuous full-length inspection using Acoustic Resonance Technology (ART) and another for targeted localised inspection using Alternating Current Field Measurement (ACFM) and Phased Array Ultrasonic Testing (PAUT). The primary case study focuses on two subsea crude oil pipelines at a terminal in the Bahamas. Each pipeline exceeded 1.2 km in length, featured complex geometry including a near-vertical 24 m riser, and had no pigging infrastructure, only a single entry and exit point. Internal conditions included residual sludge and crude oil.

A bi-directional inspection approach was used to capture complete 360° wall thickness data. ART enabled wall loss measurements through contaminated internal surfaces, eliminating the need for prior cleaning. The crawler system maintained traction throughout bends and high-friction vertical sections, completing both inspections within four days.

A second case involved the inspection of a 110 m vertical offshore riser with recessed welds and multiple 3D bends. ACFM and PAUT modules were used for targeted weld and corrosion assessment. These examples demonstrate the applicability of internal crawler-based inspection in situations with limited access or geometric complexity where conventional ILI or external NDT methods are not feasible.

A 16 x 20-inch pipeline requires a series of dual diameter pigs to flood the line for hydrotest and subsequently dewater all from shore to offshore using a nitrogen compressor spread. This paper outlines the challenges and solutions adopted in terms of pig design and testing, pig train design, flooding and pipeline dewatering to achieve the required dryness at the end of the pre-commissioning exercise.

At the end of a platform’s life and that of its associated pipelines, decommissioning must of course be carried out as safely and economically as possible. Subsea work vessels can significantly increase project costs, so minimising their use is highly desirable for operators.

Where there is a risk that flushed and decommissioned subsea pipelines could become repressurised, such as from leaks via subsea manifolds or wellheads, subsea isolation is essential to protect the environment and meet decommissioning obligations.

Remotely controlled (tether-less) isolation plugs are generally available in sizes above 10” but come with added cost due to their additional functionality. In contrast, tethered plugs are a more cost-effective option, available in smaller sizes, and are a suitable solution where the number and type of bends allow pigging to the isolation point. Many smaller pipeline systems, particularly those serving satellite platforms in marginal fields, can benefit from tethered isolation systems during decommissioning.

For the first time, a tethered 8" isolation plug was deployed from a platform to a subsea isolation point, marking the longest known deployment of its kind with a pigging distance greater than 100 metres. Once the plug was set and leak-tight isolation confirmed, the control umbilical and 8" riser were cut, effectively permanently abandoning the plug and allowing topside decommissioning to proceed.

By applying proven isolation technology in a novel way and leveraging a large, readily available UK fleet, this solution offers a cost-effective method for platform-to-pipeline isolation during decommissioning.

Pigging multiple tools in a pipeline over long distances may be done regularly but presents its own challenges. Two or more pigs, inserted for different purposes, have to travel the full distance of the pipeline and negotiate any features within it. At the same time, they must ensure the distance between them does not reduce to the point of contact, with the potential of obstructing their pigging performance.

Pigging of inline isolation tools meet the same requirements while its design, being it linked (articulated?) modules, overall length, weight, and it’s hard outside diameter close to the inner diameter of the pipeline, defying (or challenging the) basic pigging principles. A mid-line isolation typically requests the two isolation tools to be as close as possible to each other whilst the long distance pigging of two tools requires the distance between them to be kept to a maximum.

This project details the isolation of a 42” gas export pipeline, using two inline isolation tools set 12km from the launch site on either side of a valve station to enable depressurization for replacement of the inline gate valve.

On completion the two isolation tools were pigged 670km through the subsea section to the receive site, as reversing the tools back to launch size was not an option. At the receiving end further isolation activities were required and successfully completed. Finally, both isolation tools were safely recovered without any issues, damages nor notable wear of any parts. Apparently, this set an industry record in long distance pigging of inline isolation tools.

The coming together of the tools was not an option, with meticulous engineering planning along the way. This presentation covers the up-front planning as well as the use of inline isolation systems to ensure all of the challenges are met.

Trapil, the French leader in the transport of energy products by pipeline, has been developing and operating inspection tools for over 40 years to detect corrosion, metal loss, geometric defects, cracks and laminations that can affect pipelines.

With the advent of phased array technology and the increasing frequency of inspections due to the demand for ever more abundant, reliable and accurate data, the amount of data recorded by ILI tools for analysis has recently increased dramatically. Managing this massive flow of data is a major challenge for ILI operators, who are committed to maintaining the highest quality of service for their customers while minimising report delivery times. To meet these new challenges, TRAPIL has launched an ambitious research programme based on advanced AI technologies. Initially dedicated to the search for geometric faults and missing metal, this presentation will focus in particular on crack detection and identification, the results obtained and their effect on the ILI data analysis process.

This tutorial focuses on the inspection of unpiggable and difficult-to-access pipelines—systems that present unique challenges to traditional in-line inspection (ILI) methods due to design, operational, or physical constraints. While conventional "pigs" are effective for many pipelines, others remain challenging because of factors such as small diameters, tight bends, low-flow conditions, and the absence of pig traps.

Participants will gain a clear understanding of the evolving classifications of piggable, challenging, and unpiggable pipelines, and how technological advancements have transformed previously unpiggable lines into manageable inspection targets. The course will examine asset-specific integrity threats across various pipeline types, including facility and process pipelines, gas distribution systems, in-field gathering lines, loading lines, and offshore subsea pipelines.

Through a structured classroom format, the tutorial will explore cutting-edge inspection technologies such as low-pressure/low-flow tools, bi-directional ILI tools, robotic inspection vehicles, and non-intrusive external inspection methods. Real-world case studies will highlight successful adaptations and retrofits that have enabled effective data collection and improved pipeline integrity management.

By the end of the session, attendees will be equipped with practical insights into inspection planning, technology selection, and risk-based decision-making. Combining theory with practical examples, the course aims to demystify the concept of “unpiggable” pipelines and present proven strategies to safely assess and maintain these critical infrastructure assets.