Borehole compensated oxygen activation nuclear well logging
US4501964A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Aug 3, 1981 |
| Grant date | Feb 26, 1985 |
| Priority date | — |
| Expiry date | Aug 3, 2001 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/102
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Formations adjacent a well borehole are activated with neutrons from a pulsed neutron source in a sonde at an energy level, such as 14 MeV, to energize oxygen present in the formation and borehole, giving rise to gamma radiation from O.sup.16 (n,p)N.sup.16 reaction. Gamma radiation in the energy windows 3.25-4.00 MeV and 4.75-7.20 MeV is detected in a time gated detector and counted. Count rate contributions from the borehole and from the formation are differentiated on the basis of radial distance from the center of the sonde. In this manner, compensation for adverse effects of borehole oxygen activation on formation oxygen activation measurements of interest is achieved. Further, the neutron output intensity of the pulse neutron source may also be measured.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.