Pipeline circumferential weld defect safety evaluation method

Abstract

The invention discloses a pipeline circumferential weld defect safety evaluation method. The circumferential weld non-destructive detection adopts a detection method combining rays and ultrasound, andthe steps are: carrying out detection result evaluation on the external detection result of a circumferential weld, and if the evaluation results of the ray and ultrasonic detection results are bothII-level or below, ending the circumferential weld safety evaluation, and safely operating; if any judgment result of the ray and ultrasonic detection is more than II level or higher defects, carryingout size regularization processing through a defect regularization processing principle; evaluating the defects after the size regularization, and for the defects which pass the applicability evaluation, ending the safety evaluation, and safely operating; and for the defects which do not pass the applicability evaluation, carrying out reinforcing repair, depressurization operation or pipe replacement work. By using the pipeline circumferential weld safety evaluation method and process, the safety of common circumferential weld defects such as cracks, air holes, incomplete penetration, incomplete fusion, slag inclusion and undercutting can be effectively evaluated, and suggestions are provided for integrity management and maintenance of the pipeline.

Description

technical field [0001] The invention belongs to the technical field of integrity evaluation of oil and gas pipelines, and relates to a safety evaluation method for pipeline girth weld defects. Background technique [0002] Oil and gas pipeline transportation plays an important role in the national economy, but once an oil and gas pipeline fails, it often causes huge economic losses, environmental pollution and casualties. Girth welds are often the weakest link in pipeline safety, because it is not uncommon for oil and gas transmission pipelines to fail due to girth weld defects. According to the statistical results of the Office of Pipeline Safety (Office of Pipeline Safety), from 1985 to 1996, the failure rates of pipelines carrying dangerous liquids and natural gas pipelines due to pipeline girth weld problems accounted for 12% and 8% respectively. In my country, the problem of pipeline failure caused by girth weld defects is particularly prominent, accounting for about 1...

AI Technical Summary

Problems solved by technology

Due to the disadvantages of dimensional quantification of radiographic testing and ultrasonic testing (radiographic testing is sensitive to volumetric defects, qualitative and intuitive, and cannot quantify the depth of defects; ultrasonic testing is more effective for crack-type defects, which is not easy to determine, and has a large influence of human factors), so The combination of radiographic testing and ultrasonic testing is adopted, and at the same time, in order to meet the applicability evaluation, it is necessary to establish the principle of regular processing of excessive defect sizes, and there is no practical and effective size regular processing method at home and abroad.

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