The invention discloses a method for monitoring defects of a high-temperature
steam injection pipeline. An embedded probe is connected with a probe interface of a coupler; an exciting circuit is connected with an excitation source interface of the coupler; an input end of a
signal conditioning circuit is connected with a
signal conditioning interface of the coupler, and an output end of the
signal conditioning circuit is connected with a
data acquisition card interface of a computer acquisition and
processing system; the excitation source inputs a pulsed
excitation signal to the embedded probe through the coupler, excites ultrasonic guided-
waves in the pipeline, and generates ultrasonic echoes when encountering the defects, the ultrasonic echoes are transmitted to the embedded probe and are converted into
voltage signals through the embedded probe; the
voltage signals are transmitted to the
signal conditioning circuit to be processed through the coupler and are output to the computer acquisition and
processing system which acquires, processes and displays the ultrasonic echo signals containing defect information. The embedded probe can be embedded in an insulating layer of the pipeline, and the insulating layer of the high-temperature
steam injection pipeline does not need to be damaged basically, but online detection and long-term monitoring for the defects of the pipeline can be realized, and the defects of the pipeline can be simply and accurately positioned.