PPSA Seminar

In the world of hydrocarbon pipeline transportation, there are a variety of special fittings in pipeline designs that create challenges for proper in-line inspection (ILI). For example, there are a number of different pieces of equipment for connecting pipelines on the seabed such as end connectors - Hydrocouples and misaligning flanges (MisAligning Flange-MAF), which have a particular internal geometry and represent a challenging obstacle for ILI tools. In many cases these non-standard fittings are unknown to pipeline operators due to the age of the pipeline and/or lack of documentation during their design and construction. This paper describes a customized solution designed specifically for the operator of an offshore multiphase pipeline in the Gulf of Mexico, which allows such installations to be safely negotiated with an ILI tool. This solution makes it possible for pipeline operators to gather data from the entire length of the pipeline for their integrity management, even in the presence of hydrocouples and MAF flanges.

Pig tracking using electromagnetic (EM) transmitters is not a new concept, yet we are still uncovering ways to improve detection. As an example, the industry standard frequency for EM transmitters used in pigging applications is 22Hz however after extensive testing and by applying the science, it is now becoming evident 22Hz is not the optimal frequency for pig detection. We can now look at the actual performance of different frequencies in a variety of pig tracking applications and how this affects the task at hand. We have always known that signal strength can be affected by project specific factors such as pipeline diameter, material & wall thickness, pig design, pig velocity and if the pipeline is buried or subsea. However, in addition to frequency, we now know that the specification and configuration of the transmitter itself can also have a significant impact.

This paper will detail the factors that have previously been overlooked when trying to optimise pig detection and will provide recommendations on how to positively impact the effectiveness of this task. It will evidence this using a recent example whereby we carried out comprehensive “real life” testing prior to a project to ensure that the EM transmitters were configured to ensure the highest probability and greatest efficiency of detection while meeting the battery life constraints. It will also answer the question……..Is there any logic in specifying an EM transmitter’s performance by distance through air?

The self-propelled tool is driven by electricity. As for the dynamic drive system, its gradeablity is limited by the adhesion of electrically driven drive wheels and the transient discharge ability of high energy disposable lithium batteries. At present, in terms of its gradeability and downhill-slope force, the slope angle is not more than 45 degrees and the slope length is not more than 50 meters. A pneumatic drive would be needed as a supplement when there is insufficient electrical drive. The case described in this paper adopts such a method that uses blank pipe airflow to form driving differential pressure to supplement electrical drive in the case of having no back pressure on the pipe and under the discharge condition of the detector.

Adding a leather cup structure on the tool with some lift-off space to the pipe, namely: that the cup is not in contact with the pipe wall, will form a 5% discharge flow, with no frictional drag. The spreading of the cup will form a thrust force on the detector to make it run smoothly, which uses mass flow, equivalent air volume air compressor to generate pneumatic thrust force. Electric drive will supplement pneumatic drive when passing bends and pipe sections with increasing wall thickness and unbalanced resistance, and pneumatic drive will supplement electric drive when climbing. Electric drive and pneumatic drive help maintain balanced running resistance of the detector, so as to achieve smooth running. The above-mentioned dynamic balancing process has been verified on trial. To date, Φ711, Φ1067, Φ1219, , pneumatic-electric hybrid self-propelled tools have been used in real project.

Weekly pigging of a pipeline is a typical regime employed on many pipelines around the world. However this simple activity becomes costly when at one particular asset, every-time a pig is launched the emergency shutdown valve has to be activated resulting in a days lost production.

Development of a Multiple Pig Launching system that could be retrofitted to existing pig launchers with no / minimal invasive activities could reduce the number of times in a year that the ESD valve would need to be operated.

Inpipe ProductsTM designed, manufactured and tested a multiple pig launching system that allows a number of pigs to be launched individually without the need to open the closure door in-between launches.

This paper describes the key stages of development engineering and testing to create a successful conclusion to the original scope.

A routine sphering operation to control liquid hold up on a 30-inch trunk pipeline transporting wet gas was interrupted when a sphere became damaged and stalled in the pipeline following interaction with a subsea valve inadvertently stuck in the partially closed position. Rectifying the valve to the fully open position followed by rescue pigging was selected as the remediation strategy. The offshore platform topsides facilities however were only designed to launch spheres through a side branch of a tee and included a 30” to 36” reducer and 1.5D bend. The rescue pig required careful selection and sufficiently representative onshore pigging trials were then undertaken resulting in identifying numerous issues requiring extensive modifications to the rescue pig design and set up to before it was finally demonstrated the rescue pig could successfully traverse all the features in the topsides pipework. Following a successful subsea intervention campaign to fully open the subsea valve, the rescue pig was deployed and successfully recovered the damaged sphere from the pipeline. This paper and associated presentation describes the details of the various challenges and solutions that enabled an outcome of a safe and successful rescue pigging operation.

In-line inspection (ILI) is a pipeline assessment method used by operators to receive a comprehensive integrity assessment of their pipeline. However, ILI may become unfeasible due to factors such as insufficient flow/pressure parameters for propulsion, pipeline features such as valves, back-to-back elbows and unbarred tees, as well as the lack of infrastructure such as launcher and receiver for tool entry and exit. These pipelines are deemed as difficult to inspect, or “unpiggable,” and are often limited to other integrity assessment methods such as Direct Assessment or hydrostatic testing.

The fleet of robotic inline inspection robots, known as the Pipe Explorer, from Intero Integrity Services, is powered by rechargeable batteries and can travel up to 600 meters under live gas conditions before returning to the size-on-size hot-tap fitting or point to point with the use of an exit hot-tap fitting. The inspection distance may also be extended by cascading in-line-charge (ILC) stations until the desired inspection length is obtained. With Intero’s in-line charge system, Pipe Explorer is charged in-line and subsequently may continue the inspection to the next ILC station or receiver hot tap fitting.

This paper reviews the process, execution, and data from the use of robotic inline inspection for inspections that are several kilometres in length by examining a 3.5 km, two day inspection. This inspection utilized two hot tap fittings for entry and exit, as well as three charge points. The comprehensive magnetic flux leakage (MFL), deformation, and video data provided the operator with the integrity information required for continual undisrupted operation of an otherwise unpiggable pipeline.

Equinor performed decommissioning of the Veslefrikk field in the North sea Q1 2022. One of the first task after Cease Of Production was to decommission two export pipelines, one 10¨ Gas export pipeline and one 16¨ Oil export pipeline. This paper will focus on cleaning of the 16¨ Oil export pipeline. This pipeline is connected to a wye with Oseberg C export pipeline after 25 Km and total length is approx. 37 Km. The task was to clean, cut and isolate the pipeline up stream wye while there was production from Oseberg C.

This paper will cover the following topics: Government requirements, precleaning, wax, planning of the decommissioning pig train and the cleaning result.

The Pipeline Operators Forum (POF) maintains a number of standards and recommended practices related to ILI.

The recommended practice for ILI Field Verification (POF 310) was first published in 2012 and concentrated on issues including location of pipe joints in the field and verification measurements of metal loss features.

During 2022, a POF working group, with input from member operating companies and ILI & NDT contractors, has revised the document to reflect advances in the ILI & NDT industry, including recommendations for verification of a wider range of anomaly types (e.g. cracks) and high level guidance for verification of ILI findings in subsea pipelines.

The paper summarises the contents of the POF recommended practice with particular emphasis on crack detection.

Equinor, a North Sea operator, required an inline inspection of a subsea pipeline used for transporting gas and gas condensate from a subsea template to a platform that was essential to the company’s ongoing operations. To assess the conditions of the critical parts of this asset, which had never been inspected, 720 m of 10" diameter flexible riser and end fittings needed to be examined.

This paper will explore the practical application of NDT Global's, bi-directional, free-swimming, ILI ultrasonic (UT) tool, to provide unique insights into the condition of the flexible riser - including stretching of the inner carcass and the end fitting position status.

In-line inspection (ILI) has been widely adopted as a key source of data for the integrity management of traditional rigid steel pipelines. In the case of flexible pipelines however the deployment of ILI technologies remains an unfulfilled aspiration.

After some early investigations within ROSEN into the development of an ILI tool that can inspect multi-layer unbonded flexible pipes, a more focused R&D project was kicked off in 2019. This initiative resulted in significant progress in understanding the key inspection challenges and also resulted in the adaptation and development of existing technologies to be able to provide a base level of inspection in flexible pipes.

Since this time, ROSEN has also significantly enhanced capabilities in the deployment of different inspection technologies in a number of challenging offshore applications.

This paper provides an overview of the challenges faced by operators in managing flexible pipe integrity, the current state of development in ROSEN’s flexible pipe ILI capabilities and then explores some of the potential [and perhaps novel] solutions for deployment of such inspection systems.