Comparison between ECDA methods for corrosion and coating survey of underground pipeline

摘要

Coating survey of underground pipelines is very important to prevention of corrosion. According to NACE SP0502 standard, there are 3 famous methods for coating survey: DCVG, CIPS and C-SCAN. Other methods (ACVG, PEARSON, ...) aren't conventional. All methods have some advantages and disadvantages individually that limit their application. In this project, the coating of 127 km oil underground pipeline surveyed by 3 methods (DCVG, CIPS and C-SCAN). To evaluation the validity of results, some defects selected for excavation. The excavations showed that these 3 methods have different precision to distinguish coating defect locations. Then the results categorized according to defect dimension and signal intensity and compared statistically. According to these categories, the advantages and disadvantages of these 3 methods were obvious completely. The results help to select the best method for coating survey of underground pipeline based on coating type , soil resistivity , depth and cathodic protection conditions.