First implementation of in-line eddy current testing technology for pipeline corrosion in Northwest Oilfield Branch
[ China Instrument Network Instrument R&D ] Recently, the Northwest Oilfield Company successfully applied eddy current testing technology for the first time and successfully completed the construction of TP13 metering station DN200 through Tahe crude oil pipeline. The successful application of the eddy current testing technology not only clarified the service conditions and safety risks of the pipeline, but also provided another testing method for the integrity management of oil and gas fields.
Pipeline operation safety is the foundation of the pipeline industry, but statistical analysis of pipeline accidents at home and abroad shows that most pipeline accidents are caused by failure to detect and identify pipe defects or inaccurate discrimination of defect types and quantified dimensions. Therefore, discovering and repairing pipeline defects through various inspection technologies is an important means to improve the safe operation level of pipelines.
Among them, one of the main causes of pipeline accidents is the cracking of girth welds, which not only makes it easy to pose serious threats to the safety of surrounding personnel and the environment, but also makes repair work difficult, requires strict pipeline shutdown, and has many sensitive environmental points. Evaluating and repairing defects in girth welds to ensure the intrinsic safety of pipelines has important economic and social significance. Therefore, the internal inspection technology of the girth welding seam has become a research hotspot at home and abroad.
However, due to the particularity of the position of the girth weld defect, it is quite difficult to identify and quantify the defect size through internal inspection. For example, the Guochuanhe pipeline not only limits the detection method, but also has a relatively high risk. Routine internal and external detection technologies are not covered by water-covered causes; leak detection techniques have the disadvantage of large volume of detection equipment. There is a high risk of jamming in the reach of the river; piezo-ultrasonic techniques require the application of a coupling agent and are not suitable for environments such as natural gas pipelines. The parameter design process of the coil part of the electromagnetic ultrasonic testing technology mostly depends on the engineering experience, line width, line spacing and other parameters, after many exchanges, eddy current in-house detection technology stands out.
Eddy current testing is a non-destructive testing method for the surface or near surface. The detector does not need to be in close contact with the material to be inspected, and no coupling agent is required. The internal detection has good passability and high detection accuracy. It is especially suitable for the detection of small-diameter pipes below DN200. . In order to ensure the smooth implementation of eddy current testing, Deputy Director Chen Xiaohua of the Institute of Anti-corrosion in person led the team. After ten days of intense construction, the eddy current testing for the first time through the river was successfully completed.
In this test, a detailed evaluation of the corrosion status of the pipeline through the river was made, and technical conclusions were made as to whether the pipeline could continue to be serviced safely. At the same time, it was also a problem for the detection of girth weld defects by internal and external major pipeline operators and testing service providers. Filling the gaps will help reduce the risks of the pipeline and ensure the intrinsic safety of the pipeline.
(Source: Sinopec News Network, PIMC Oil and Gas Pipeline Integrity, China Optical Journal Net)