Active damping for multi-frequency NMR logging tools
US10585205B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jan 18, 2018 |
| Grant date | Mar 10, 2020 |
| Priority date | — |
| Expiry date | Feb 8, 2038 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01R33/3671
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for performing a nuclear magnetic resonance (NMR) experiment in a borehole penetrating the earth includes: a carrier configured to be conveyed through the borehole; an antenna assembly disposed on the carrier and configured to receive an NMR signal; and an active gain circuit having an input coupled to the antenna and configured to apply gain to the received NMR signal and to provide an output signal comprising NMR experiment data. The apparatus also includes a feedback circuit configured to feed the output signal back to the input of the active gain circuit; wherein the signal fed back to the input of the active gain circuit is out of phase with the received NMR signal and the feedback circuit provides an electrical quality factor Q value of an antenna assembly that is less than the electrical quality factor Q value of the antenna assembly without the feedback circuit.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.