Pipeline Integrity – Crack Sizing using Tangential Eddy Current Array (TECA™) Technology

Raude, Angélique; Eddyfi Europe; France

Bouchard, M.; Eddyfi; Canada
Raude, A.; Eddyfi; Canada
Sirois, M.; Eddyfi; Canada

ID: ECNDT-0238-2018
Session: Oil & Gas 1
Room: H2
Date: 2018-06-11
Time: 14:30 - 14:50

In-the-ditch inspection for fatigue cracking and crack colonies is an integral part of pipeline condition assessment programs. Such types of flaw are typically detected by Magnetic Particle Inspection (MPI). Quantitative depth sizing is then either achieved by sequential grinding or by Ultrasonic Testing (UT). This procedure, albeit useful, is time-consuming, weather-sensitive and user-dependant. Integrating crack detection and sizing in a single step would significantly shorten excavation inspection and repair time, thus costs.

Recent advances in Eddy-Current Array (ECA) coil design and multiplexing patterns enabled crack detection and sizing in ferrous materials. The main objective behind the development of these new Tangential ECA (TECA) probes was to determine the optimal set of parameters to obtain a clear discrimination between surface breaking defects, lift-off and permeability changes while still being able to monitor and quantify each signal individually. By multiplexing and leveraging advanced data processing capabilities, this ECA solution allows inspections to be carried out quickly, provide accurate depth sizing of cracks and eliminate the need to remove protective coatings. This new approach offers additional benefits such as state-of-the-art imaging (e.g. 2D and 3D C-Scan displays), improved surface coverage, ease of deployment and data archiving. Furthermore, the new sensors and technique developed allows inspections to be carried out under the mainstream ECT certification.

This paper describes the application of Tangential Eddy Current Array on pipelines for the detection and sizing of cracks. Specifically, the development consists of dedicated multichannel probes connected to a portable acquisition system.

Numerous tests were conducted on both manufactured and real defects decommissioned samples. The result is two array probes deployable on various pipe diameters ranging from 25 cm (10”) and capable of detecting surface breaking indications such as fatigue cracking in welds and cracking colonies in parental material. Such defects are now detected and sized with ±10% accuracy while lift-off is monitored and dynamically compensated. Potential to replace MPI and UT as the industry gold standard for fast and reliable crack detection and sizing on carbon steel pipelines is shown.