Method for reducing ringing in nuclear magnetic resonance well logging instruments
US6498484B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 15, 2000 |
| Grant date | Dec 24, 2002 |
| Priority date | — |
| Expiry date | Sep 11, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N24/081
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for reducing ringing in nuclear magnetic resonance measurements is disclosed. The method includes inducing a static magnetic field in a sensitive volume to orient nuclear magnetic spins of nuclei in the sensitive volume. The nuclear spins are reoriented by a first selected angle. An amplitude of the static magnetic field is then adjusted to cause a first selected phase shift in a spin echo signal measured subsequently to the reorienting by the first angle. The spins are then reoriented by a second selected angle, and a first spin echo signal is detected. After a selected wait time, reorienting by the first selected angle is repeated. Adjusting the amplitude of the static magnetic field is then repeated to cause a second selected phase shift in a subsequently measured spin echo. The first and second selected phase shifts have a difference between them of an odd numbered multiple of 180 degrees. Reorienting by the second selected and detecting a second spin echo signal are then repeated. Finally, a difference between the first spin echo signal and the second spin echo signal is determined. In one embodiment, the measuring of the first and second spin echoes is repeated a sel…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.