Corrosion monitoring with tangential radiography and limited view computed tomography

Abstract

Abstract. Accurate and reliable detection of subsea pipeline corrosion is required in order to verify the integrity of the pipeline. A laboratory trial was conducted with a representative pipe sample. The accurate measurement of the wall thickness and corrosion was performed with high energy X-rays and a digital detector array. A 7.5 MV betatron was used to penetrate a stepped pipe and a welded test pipe of 3 m length and 327 mm outer diameter, with different artificial corrosion areas in the 24 mm thick steel wall. The radiographs were taken with a 40 x 40 cm² digital detector array, which was not large enough to cover the complete pipe diameter after magnification. A C-arm based geometry was tested to evaluate the potential for automated inspection in field. The primary goal was the accurate measurement of wall thickness conforming to the standard. The same geometry was used to explore the ability of a C-arm based scanner in asymmetric mode for computed tomography (CT) measurement, taking projections covering only two thirds of the pipe diameter. The technique was optimized with the modelling software aRTist. A full volume of the pipe was reconstructed and the CT data set was used for reverse engineering, providing a CAD file for further aRTist simulations to explore the technique for subsea inspections.

FBG-Based Accelerometer for Buried Pipeline Natural Frequency Monitoring and Corrosion Detection

“…Radiography is also utilized for corrosion monitoring, as can be seen in [20,21], and it consists of an analysis of the differences in attenuation of the penetrating radiation in materials, depending on their composition, thickness, density, and other aspects [22]. Other studies have used this technique for evaluating corrosion in pipelines, as reported in [23], where the authors utilized two methods for its analysis, tangential radiography and double wall radiography, and concluded that those methods were capable of identifying variations of 10%, 20%, and 50% in the thickness of a pipeline with a 150 mm diameter.…”

A Review of the Real-Time Monitoring of Fluid-Properties in Tubular Architectures for Industrial Applications

“…Using distributed acoustic sensors along the pipe at discrete distances acoustic emissions can be used to detect cracks and leaks [20,21]. Similarly, other types of sensors can be used, such as ultrasonic sensors [22,23], radiography monitoring [24,25], and eddy current [26]. The authors of [27] reviewed the different pipe monitoring and leaking detection technologies.…”

Current deflection NDE for the inspection and monitoring of pipes

“…Radiography has been successfully applied to the inservice detection of corrosion under insulation in pipelines [19,20,21]. Through transmission radiography requires access to both sides of the pipe, and for large diameter pipes, either gamma ray or high energy X-rays must be used in order to propagate over such a large distance between source and receiver [22,23,24]. Back-scatter radiography may be used when there is access to only one side of the pipe although the scattered radiation is diffuse (non-imaging) and of a low intensity [22].…”