Preconditioning spins near a nuclear magnetic resonance region in a borehole
US6844728B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jul 18, 2002 |
| Grant date | Jan 18, 2005 |
| Priority date | — |
| Expiry date | Jul 18, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N24/081
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method and an apparatus for obtaining NMR measurements are disclosed. An NMR measurement apparatus, the measured sample, or both elements may be subjected to motion during the measurement. The envelope of an RF carrier signal is modulated according to an envelope to generate a first sequence of RF pulses. The envelope, the phase of the RF signal, and/or a static magnetic field may be varied during the radiation of the first sequence to substantially saturate a first region of the sample. The first sequence may include additional RF refocusing pulses that, when coupled with movement of the NMR measurement apparatus or sample, may also be used to substantially saturate the first region. A second sequence of RF pulses is radiated to establish a resonance region within the first region and measure an attribute of the sample.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.