Method for evaluating damage severity degree of external anticorrosive coating of pipeline

Abstract

The invention discloses a method for evaluating the damage severity degree of an external anticorrosive coating of a pipeline, which comprises the following steps of: applying a specific detection signal to the pipeline, detecting and positioning a damaged point of the external anticorrosive coating of the pipeline by using an alternating-current ground-potential gradient method, and recording the potential difference value of the point; measuring and recording the buried depth of the pipeline at the damaged point of the external anticorrosive coating of the pipeline; measuring and recording the currents of a pipeline current surveying and mapping system on both sides of the damaged point of the external anticorrosive coating of the pipeline, so as to obtain the average of the two currents as the current value of the pipeline current surveying and mapping system for correction at the damaged point; according to the measured potential difference value, the signal current flowing in and out of the damaged point, the distance value of an A-shaped frame and the buried depth at the center of the pipeline, calculating the corrected potential difference value; evaluating the damage severity degree of the external anticorrosive coating of the pipeline by an evaluation criteria. By adopting the method for evaluating the damage severity degree of the external anticorrosive coating of the pipeline, disclosed by the invention, the severity degree of the damaged point of the anticorrosive coating of the pipeline can be evaluated accurately, thereby facilitating the engineering construction.

Description

technical field [0001] The invention relates to the field of drilling, in particular to a method for evaluating the damage severity of an outer anticorrosion layer of a pipeline. Background technique [0002] The outer anti-corrosion layer of buried pipelines is an important measure to slow down the metal corrosion of the pipe body. The commonly used anti-corrosion layers include petroleum asphalt, epoxy coal tar pitch, epoxy resin, polyethylene tape, "yellow jacket", two or three layers of PE Wait. With the increase of running time, due to joint defects, poor construction quality, man-made damage and natural aging, the anti-corrosion layer will be damaged to varying degrees, resulting in corrosion and leakage of the pipe body. Therefore, it is of great significance to find out the exact location of the damaged point of the anticorrosion layer and the severity of the damage, and take timely maintenance measures to ensure the long-term, stable and safe operation of buried pi...

AI Technical Summary

Problems solved by technology

However, in the current actual detection process, through the research on the principle of the method and the actual excavation and repair experience, it is proved that the use of the detected potential difference to directly evaluate the severity of the damage of the anti-corrosion layer is quite different from the actual situation.

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