Nuclear magnetic resonance well logging method and apparatus
US6570381B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 25, 1999 |
| Grant date | May 27, 2003 |
| Priority date | — |
| Expiry date | Mar 25, 2019 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N24/081
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates generally to a nuclear magnetic resonance apparatus and method for substantially eliminating the effects of phase coherent acoustic ringing in borehole logging. A series of cycles of measurement pulse sequences are applied to the formation surrounding the borehole. Each pulse sequence includes an RF excitation pulse and several RF refocusing pulses. Spin echoes are received that contain spurious ringing signals from the excitation and refocusing pulses. Spin echo signals from corresponding spin echoes of each cycle are combined and substantially cancel the spurious ringing from the excitation and refocusing pulses of the pulse sequences.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.