Session: 03-03-08 Feature Assessment Case Studies - Selective Seam Weld Corrosion I

Paper Number: 133624

133624 - Getting to the Bottom of the Groove: NDE of SSWC 

Abstract: 

Selective seam weld corrosion presents a set of unique circumstances that results in difficulty in accurately determining the groove depth. Classification and measurement of in-the-ditch selective seam weld corrosion (SSWC) has proved difficult due to many factors. On the classification side, lack of fusion (LOF) and SSWC often look similar and distinguishing between the two can prove challenging. Visual difficulties can then result in an incorrect classification which may affect the determined remaining life or repair criteria. On the sizing side, measuring the depth of narrow SSWC or SSWC with surrounding general corrosion proves challenging to use pit gauges or phased array. Surrounding external corrosion creates a difficult surface to land the NDE equipment and tight features prevent the use of hand tools, such as pit gages from reaching the bottom of the groove. Lack of a defined procedure can lead to a varying level of success when inspecting these features. Accurate depth measurements are critical when determining a fitness for service, remaining life, or even the appropriate repair method.

This paper focuses on the main task of a recent Pipeline Research Council International project, PRCI NDE 2-15, whereby the goal was to develop in-the-ditch evaluation methods and necessary tools to address difficulties associated with determining SSWC depth. Through a series of targeted NDE, a specialized NDE procedure was developed to identify external SSWC verses other defects such as lack of fusion or seam trim and measure external SSWC depth and length. In some cases, this NDE procedure combines multiple NDE techniques, each building on each other to determine the grooving depth. Finally, this protocol was validated through metallurgical examination.

This paper provides a first of its kind to provide the pipeline industry with guidance when attempting to inspect and properly classify SSWC. This paper provides the first step to gaining a better understanding of SSWC inspection.

Presenting Author: David Futch ADV Integrity

Presenting Author Biography: David Futch has worked in the oil and gas industry experience since 2012, specializing in midstream pipeline materials, welding, and corrosion. At ADV Integrity, he guides clients through failure analysis programs, repair technique selection, material degradation phenomena, material selection, and welding related issues.

Authors:

David Futch ADV Integrity
Chris Newton P66