Method for measuring stress of in-service oil and gas pipeline by using bidirectional ultrasonic probe

Abstract

The invention discloses a method for measuring the stress of an in-service oil and gas pipeline by using a bidirectional ultrasonic probe, which comprises the following steps of: manufacturing a bidirectional zero-stress tensile test piece, and pasting two direction strain gauges on one side of the bidirectional zero-stress tensile test piece; coupling the other side of the bidirectional zero-stress tensile test piece by using a bidirectional ultrasonic probe; performing a plurality of groups of two-way tensile experiments on the two-way zero-stress tensile test piece; recording the strain epsilon x and epsilon y in the X direction and the Y direction in a plurality of groups of tension states and the corresponding ultrasonic flight time tx and ty; and fitting quantitative relational expressions epsilon x = kx delta t = kx (tx-t0) and epsilon y = ky delta t = ky (ty-t0x + tc) of the strain and the ultrasonic flight time to obtain stress coefficients kx and ky, and obtaining the axial stress and the circumferential stress of the pipeline by measuring the pipe diameter, the wall thickness and the internal pressure of the field to-be-measured pipe section and combining the stress coefficient k. According to the invention, the axial stress on the surface of the pipeline can be quickly and accurately measured, the problems of zero stress calibration and inaccurate stress value in the prior art are solved, and the credibility of the detection result is greatly improved on the basis of the existing ultrasonic stress measurement technology.

Description

Technical field [0001] The invention involves the field of stress measurement technology, especially a method that uses a two -way ultrasound probe to measure the stress of oil and gas pipelines in service. Background technique [0002] Pipe stress lossless detection is one of the most important technologies in the process of pipeline safety inspection. Its characteristics of no damage to the pipeline can ensure that the pipeline quickly obtains the current stress state in the operation state, judge the current level of stress of the pipeline, and evaluate the remaining security of pipelines. The key to the stress non -destructive detection technology is the calibration of zero stress state, which determines the accuracy of the measurement results of various detection methods. [0003] At present, the tested method of oil and gas pipelines in public includes damage detection methods and non -destructive detection methods. The damage detection method is also called mechanical meth...

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to provide a method for measuring the stress of oil and gas pipelines in service by using a two-way ultrasonic probe to solve the above problems. The problem of inaccurate calibration and stress values, on the basis of the existing ultrasonic stress measurement technology, greatly improves the reliability of the test results

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