apparatus for measuring ferromagnetic tube thickness using remote field eddy current detection, apparatus for measuring defects in a well tube using remote field eddy current measurement, apparatus for measuring defects in a tube using remote field eddy current measurement, and method for removing phantom defects from a remote-sensing eddy current detection device.

摘要

The apparatus employs the remote field eddy-current (RFEC) inspection technique to electromagnetically measure physical parameters of a metallic pipe. RFEC devices inserted into and displaced along a cylindrical pipes may be used to measure the ratio of pipe thickness to electromagnetic skin-depth and thus allow for the non-invasive detection of flaws or metal loss. Typically these RFEC thickness measurements exhibit a so-called double-indication of flaws, an undesired artifact due to a double-peaked geometrical sensitivity function of the device. The method describes a means by which this double indication artifact may be removed by an appropriate processing of RFEC measurements performed by an apparatus specifically designed for this purpose. The invention is particularly well designed for applications in the oilfield industry.