Simultaneous thermal neutron decay time and porosity logging system
US4152590A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1977 |
| Grant date | May 1, 1979 |
| Priority date | — |
| Expiry date | May 19, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/105
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A simultaneous pulsed neutron porosity and thermal neutron capture cross section logging system is provided in the present invention. A logging tool provided with a 14 MeV pulsed neutron source, an epithermal neutron detector, and a combination gamma ray and fast neutron detector is moved through a borehole. Repetitive bursts of neutrons irradiate the earth formations and, during the bursts, the fast neutron and epithermal neutron populations are sampled. During the interval between bursts the thermal neutron capture gamma ray population is sampled in two or more time intervals. The fast and epithermal neutron population measurements are combined to provide a measurement of formation porosity .phi.. The capture gamma ray measurements are combined to provide a simultaneous determination of the thermal neutron capture cross section .SIGMA..
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.