System and method for NMR logging with helical polarization
US6956372B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 11, 2003 |
| Grant date | Oct 18, 2005 |
| Priority date | — |
| Expiry date | Sep 11, 2023 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/32
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Nuclear magnetic resonance well logging apparatus and method of use for geophysical examination of a borehole as the borehole is drilled. The apparatus is connected to the drill bit to follow it through the borehole as the borehole is formed. The apparatus comprises a non-magnetic protective collar with lateral protrusions or wings, which provide enhanced abrasion resistance, strength, and rigidity to the probe section. This collar is twisted about its longitudinal axis. The apparatus also comprises one or more permanent magnets within the metal collar and an antenna mounted outside of the collar. Both the magnet and the antenna are twisted about the longitudinal axis of the probe section to produce a generally helical static magnetic field and a radio frequency magnetic field that is substantially orthogonal to the static magnetic field.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.