Laser-based external corrosion mapping of pipelines

Hardware and software advancement in computer technology enable the development of faster and better application of laser inspection technology in the field of pipe surface corrosion inspection as well as weld profile inspection. Several software programs for inspecting surface defects on pipelines have been developed by EWI within the past few years. The most recent development, utilizing an algorithm that accommodates for normal pipeline deviations such as bulges, bends and dents, was developed and incorporated into a mechanical pipeline-scanning device. This automated laser-based corrosion mapping system was designed for inspection of corroded surfaces of in-service pipelines. The new system has been used successfully for external measurement of exposed pipelines. The system is based on the use of laser spot range finders on a circumferential slide carried by a magnetically attached crawler. The crawler has the ability to auto steer to maintain its circumferential position on the pipe, and the circumferential slide allows a 100-degree segment of the pipe to be scanned. The portable system is able to map corrosion profiles in the presence of surface deviations such as ripples, bulges, and welds. A graphical user interface (GUI) allows easy data display, analysis and archiving. Results generated with the system are used in corrosion assessment procedures such as RSTRENG (3) to evaluate the condition of the pipeline and suggest the appropriate remedial action, if required.