Methods and apparatus for investigating an earth formation and compensating for borehole environmental effects
US4524274A · kind A · utility
13Cited by
8References
36Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Aug 5, 1982 |
| Grant date | Jun 18, 1985 |
| Priority date | — |
| Expiry date | Aug 5, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/10
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
In the illustrative embodiment of the invention disclosed, a neutron porosity logging tool adapted to log a mud-filled borehole includes one or more pairs of epithermal and/or thermal neutron detectors. The detector count rates are corrected to the effective count rates for fresh water in the borehole by applying thereto empirically-derived correction terms that are functionally related to the hydrogen index of the mud and, in the case of thermal detectors, also to the thermal neutron absorption properties in the mud.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.