Neutron porosity based on one or more gamma ray detectors and a pulsed neutron source
US9268056B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Mar 27, 2013 |
| Grant date | Feb 23, 2016 |
| Priority date | — |
| Expiry date | Jul 24, 2033 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/101
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for pulsed neutron well logging of a subsurface formation, includes irradiating the formation with a plurality of bursts of neutrons of a group of selected durations; detecting gamma rays resulting from interaction of the neutrons during a group of selected time gates which contains at least some early and late gamma ray counts. The gamma rays are detected at at least two axially spaced apart locations from a position of the irradiating. A weighted sum of the numbers of gamma rays detected in each of the time gates is calculated. A ratio of the weighted sum of detected gamma rays at a first axial spacing to the weighted sum at a second axial spacing is determined. The ratio is used to determine a hydrogen index of the subsurface formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.