Electromagnetic inspection tool for ferromagnetic casings
US4292588A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 18, 1978 |
| Grant date | Sep 29, 1981 |
| Priority date | — |
| Expiry date | Dec 18, 1998 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/085
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An electromagnetic thickness tool is disclosed to produce a measurement of the wall-thickness of a ferromagnetic casing corrected for the effects of casing permeability. First apparatus provides an uncorrected thickness signal proportional to the thickness of the casing uncorrected for the effects of casing permeability. A second apparatus provides a permeability signal representative of the permeability of the casing. A signal processor uses the mathematical square root of the permeability signal as a correction factor for the uncorrected thickness signal for generating the corrected value. The second apparatus, responsive to a signal proportional to the magnitude of the inside diameter of the casing, corrects the permeability signal for the effects of casing inside diameter.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.