Method and apparatus for measuring velocity of ferromagnetic tubing
US4578642A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 11, 1984 |
| Grant date | Mar 25, 1986 |
| Priority date | — |
| Expiry date | Apr 11, 2004 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/72
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A tubing trip tool for use in determining the extent of defects in tubular elements comprising a continuous string used in a subterranean oil or gas well during removal of the string from the well is disclosed. Local defects and axially extending defects, as well as the average wall thickness of the tubular elements, are measured. The position of the defects is determined by measuring the variable velocity of the tubular elements as they are removed from the well. A noncontact axial velocity detector comprises detector elements generating a first signal dependent upon an applied magnetic field and the axial velocity of the tubular elements. The first signal is compared to a signal dependent only upon the magnetic field generated in a second element. A pickup coil and Hall effect probes can be used.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.