Patent attributes
A tool disposable within a well pipe, such as for detecting a freepoint of a well pipe, includes an electromagnet capable of inducing a magnetic field within a wall of a well pipe. The tool includes a Barkhausen noise sensing device capable of sensing magnetic Barkhausen noise in response to the electromagnet inducing the magnetic field within the wall of the well pipe. The tool may be moved along the well pipe so as make two passes of the tool along the well pipe, with one pass being performed while the well pipe is less stressed and the other pass being performed while the well pipe is more stressed, with the output of the tool during a first pass being compared to the output of the tool during a second pass to determine the location of the freepoint of the well pipe.
