Experimental Study of Microstructures in Bias Weld of Coiled Tubing Steel Strip With Multi-Frequency Eddy Current Testing

Zhaoming Zhou,Yuedong Xie,Mian Qin,Jinsong Tan,Hailong Bao

doi:10.1109/access.2020.2979414

Zhaoming Zhou, Yuedong Xie + Show 3 more

Open Access

https://doi.org/10.1109/access.2020.2979414

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Journal: IEEE Access	Publication Date: Jan 1, 2020
Citations: 16	License type: CC BY 4.0

Affiliation: Beihang University, Southwest Petroleum University

Abstract

Coiled tubing technology is widely used in drilling and repairing operations, and the quality of bias weld directly determines the fatigue life of the coiled tubing. The microstructures consistency between the bias weld and the base metal determines that whether the fatigue resistance of the weld reaches the level of the base metal. In this paper, multi-frequency eddy current testing technique is used to detect the reactance of the bias weld zone and the base material zone within coiled tubing steel strip, which can be used to determine the microstructure consistency between the base metal area and the weld area, and in turn to improve the welding technology and heat treatment process. In this work, CT100 and CT90 materials with the bias weld for coiled tubing were used as the test samples, and the on-line real-time non-destructive testing technology was used to judge whether welding technology and heat treatment technology have been improved. The basis for determination is whether the mechanical properties and fatigue properties of the welding site reach the base material level. The weld zone and base metal zone can be identified by analyzing the characteristic cloud map of the detection signal, and then the quality of partial weld can be evaluated according to the difference of microstructure between them, which is of guiding significance for quality control and improvement of coiled tubing production process.

Highlights

Coiled tubing technology is a revolutionary technology in oil and gas production in the 21st century, which is widely used in workover and drilling operations
By analyzing the electromagnetic detection cloud map of the CT90 coiled tubing weld and base metal of traditional welding technology and heat treatment process., it can be found that the microstructures of bias weld and base metal produce different signals; the color of base metal zone is lighter than that of weld zone, which indicates that the reactance of base metal zone is smaller than that of the weld zone
By analyzing the electromagnetic detection cloud map of the CT90 coiled tubing weld and base metal of the improved welding technology and heat treatment process, it can be found that the microstructures of bias weld and base metal produce different signals, the color of base metal zone is lighter than that of weld zone, which indicates that the reactance of base metal zone is smaller than that of the weld zone

Summary

INTRODUCTION

Coiled tubing technology is a revolutionary technology in oil and gas production in the 21st century, which is widely used in workover and drilling operations. Multi-frequency eddy current testing technology is used to evaluate the difference of microstructure between welding seam and base material in real-time and non-contact manner, and obtain the variation of microstructure parameters of welding seam and base material quantitatively, which has important guiding significance to the coiled tubing steel strip bias weld heat treatment process evaluation and the development of the higher strength. It can replace the present lossy evaluation method which consumes a lot of samples and test time, simplifies the evaluation method of bias weld quality, reduces accidents in coiled tubing operations, and deepens the understanding of the mechanism of the relationship between microstructure parameters and nondestructive testing signals. The grain size of the weld zone is obviously larger than that of the base metal zone [27]

Test Method

RESULTS AND DISCUSSIONS

CONCLUSION