Logging apparatus and method for determining concentrations of subsurface formation elements
US5053620A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 13, 1989 |
| Grant date | Oct 1, 1991 |
| Priority date | — |
| Expiry date | Dec 13, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/06
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Method and apparatus for identifying and determining the concentrations of subsurface formation elements next to a borehole, by detecting and counting the gamma rays resulting from the activation of Al atoms by neutrons emitted by a high energy source. The total count rates from Al are corrected for Si interference by (1) calculating the ratio of the count rates of gamma rays from Si activation to the count rates of the gamma rays resulting from the inelastic collisions of neutrons with Si atoms, thus providing a reference ratio independent of environmental parameters; (2) detecting and counting the gamma rays resulting from the Si inelastic collisions; (3) determining from the count rates of silicon inelastic gamma rays and from said ratio, the count rates of Si activation gamma rays; and (4) subtracting, from the total count rates of activation gamma rays, the count rates of Si activation gamma rays. The method comprises also detecting and counting the gamma rays resulting from the capture of said neutrons by atoms of a plurality of elements.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.