Broad energy spectra neutron source for logging and method
US5097123A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 10, 1991 |
| Grant date | Mar 17, 1992 |
| Priority date | — |
| Expiry date | Apr 10, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/101
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Logging method and tool string for identifying and determining the concentrations of subsurface formation elements next to a borehole, by (i) using a broad energy spectra neutron source (such as a chemical source, like AmBe), and (ii) detecting and counting the delayed gamma rays resulting from the activation by the neutrons of atoms of least one element of interest (e.g. aluminum). Two gamma ray detectors may also be disposed on either side of the broad energy spectra neutron source, for detecting and counting the prompt gamma rays resulting from the capture of neutrons by atoms of elements, such as Si, Ca, Fe, S, H, or Cl, Gd, Ti, or K. The broad energy spectra neutron source is used for both the "activation" and the "capture" measurements. The tool string may also include a natural gamma ray tool for the determination of uranium, thorium and potassium, and for measuring the background to be subtracted from the gross Al activation measurement.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.