Session: 03-05-01 New Inspection Technologies and Facilities I

Paper Number: 133297

133297 - Development of an Ultrasonic ILI Tool for the Assessment of Crack-Type
Anomalies in Ammonia-Carrying Pipelines 

Abstract: 

The in-line inspection (ILI) of pipelines used to transport anhydrous ammonia is very challenging since several components that make up a typical ILI tool used for the inspection of oil and gas pipelines are not compatible with the anhydrous ammonia. Magnetic Flux Leakage (MFL) and Deformation (DEF) tools have been developed in the past to assess anhydrous ammonia pipelines for corrosion and deformation anomalies. However, assessing for crack type anomalies has never been possible as no ammonia compatible ultrasonic ILI tool has been developed.  Feasibility studies have in the past been undertaken to address this problem but so far none of these investigations has resulted in a successful ultrasonic ILI tool build for inspection of ammonia carrying lines. As a result, the operators of these pipelines have been conducting ultrasonic ILI inspections using water to navigate the tool through the line during a hydrotest. This process is not only expensive, but it also causes months of interruptions in flow due to repairs and other factors related to the procedure. The opportunity to be able to conduct ultrasonic (crack) ILI inspections during the normal operation of this ammonia pipeline system would result in a significant cost saving for the client.

The paper will report on the findings of the three phases of the project undertaken by NDT Global on behalf of NuStar Energy to investigate options for an ultrasonic ILI tool capable of detecting and sizing axial cracks, in particular fields of stress corrosion cracks (SCC), in ammonia carrying pipelines. NuStar Energy operates an extensive pipeline network in the US with approximately 2,000 miles of pipelines carrying liquefied anhydrous ammonia.

The first phase of this project was the feasibility study. The work was a series of laboratory-based test programs carried out to evaluate the performance of components in ammonia environment and to evaluate different options for tool modifications with the focus on compatible materials for ultrasonic technology (UT) measurement of axially oriented cracks. A significant challenge during this phase was the manufacturing of a UT sensor for this task.

The paper will also report on the results of two test runs conducted using test modules to collect performance data on the behavior of different components during an ILI run.  Each run consisted of the test modules running through a live section of ammonia carrying pipeline. At the end of each run the tool was left to soak in the receiver trap to complete over 40 hours of the tool and it's components exposure time to ammonia.

The second phase was the development of the technical concept to design and build the UT crack tool. The development phase has been completed and the tool is currently being built. Phase three is the tool qualification program which is planned for early 2024. This phase will focus on qualifying the tool and to validate its performance in ammonia environment. A full-scale ultrasonic ILI inspection will be carried out on a target anhydrous ammonia pipeline section identified by the pipeline operator. It is anticipated that the paper will include preliminary results from the qualification program and a more detailed set of results will be presented during the conference.

Presenting Author: Raymond Kare NDT Global

Presenting Author Biography: I have been working in the ILI industry developing technology for the inspection of pipelines for the past 17 years. Previously I have been working in the field of the underwater inspection of offshore structures

Authors:

Raymond Kare NDT Global
Norbert Thielager NDT Global
Maximillian Fischer NDT Global
Colton Shannon NuStar Energy