Apparatus including multi-wait time pulsed NMR logging method for determining accurate T2-distributions and accurate T1/T2 ratios and generating a more accurate output record using the updated T2-distributions and T1/T2 ratios
US5486762A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 15, 1994 |
| Grant date | Jan 23, 1996 |
| Priority date | — |
| Expiry date | Aug 15, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V3/32
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
When a pulsed nuclear magnetic resonance (NMR) well logging tool is traversing a wellbore, a NMR well logging method includes magnetizing the hydrogen nuclei in a formation traversed by the tool with a static magnetic field, waiting for a first period of time W.sub.1, energizing the formation with oscillating RF pulses, collecting a first plurality of spin echo signals, waiting a second period of time W.sub.2 which is different from the first period of time W.sub.1, energizing the formation with oscillating RF pulses, collecting a second plurality of spin echo signals, waiting a third period of time W.sub.3 which is different from both the second period of time W.sub.2 and the first period of time W.sub.1, energizing the formation with oscillating RF pulses, collecting a third plurality of spin echo signals, etc. The first, second and third, etc. plurality of spin echo signals corresponding to the different wait times are input to a signal processing apparatus disposed in the tool. Window sums of spin-echo signals are computed and transmitted uphole to a surface oriented signal processing apparatus. In response to the window sums, the surface signal processing apparatus determines …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.