Determination of water saturation in subsurface earth formations adjacent well boreholes
US4191884A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 27, 1977 |
| Grant date | Mar 4, 1980 |
| Priority date | — |
| Expiry date | Dec 27, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/102
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Gamma ray spectra of earth formations surrounding a well borehole are obtained by bombarding the formations with neutrons from a pulsed neutron source and detecting the gamma rays resulting from capture of thermalized neutrons in the formation using a germanium gamma ray detector. A measure of the ratio of chlorine to hydrogen is obtained from the detected gamma radiation spectra, and the apparent formation water salinity is determined from the chlorine/hydrogen ratio. The water saturation of the formation is then obtained from the apparent formation water salinity and the true formation water salinity. Compensation is made for the presence of saline water in the borehole fluid and in the cement annulus, as well as for any bound water in the formation.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.