Method and apparatus for measuring subsidence
US5005422A · kind A · utility
6Cited by
3References
5Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 14, 1989 |
| Grant date | Apr 9, 1991 |
| Priority date | — |
| Expiry date | Sep 14, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01V5/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention relates to a method and apparatus for measuring subsidence by evaluating the distance between radioactive markers which have previously been implanted in the formation traversed by a borehole. The apparatus comprises an elongate body containing at least two nuclear detection assemblies which are spaced apart along the longitudinal axis of the body. Each detection assembly inludes at least one position sensitive detector for detecting position along the longitudinal axis of the body. Measurements are performed while the apparatus is held stationary opposite the markers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.