Potential application of laser shearography for analysis of corrosion in petroleum pipeline

Abstract

This paper aims at assessing of corrosion defects in standard petroleum pipelines by shearography method. Shearography reveals the stress-affected zone due to additional loading that can be realized by the laser speckle correlation on the inspected object. In this study, the artificial corrosion in pipeline is modeled by creating circular defects of different depths and sizes. An internal air pressure was exerted to the 7mm thick pipe wall. The results show that change of internal pressure is an effective means to reveal corrosion activity in the pipelines. The speckle correlation for corrosion of more than 3mm depth with ▵P≥0.24MPa can clearly be observed. For comparison, radiography technique is used to correlate the depth and size of the corrosion defects and finally to detect the location of the corrosion area.