Acoustic detection of stress-induced mechanical damage in a borehole wall
US6510389B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Feb 25, 2000 |
| Grant date | Jan 21, 2003 |
| Priority date | — |
| Expiry date | Feb 25, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/2636
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method provides for locating and measuring mechanical damage in rock surrounding a borehole by detecting one or both of reductions in ultrasonic compressional wave velocity in the rock as a function of azimuth, and by detecting focused acoustic energy in the rock from local increases in ultrasonic compressional wave amplitude resulting from velocity gradients. A first preferred embodiment uses a combination of azimuthal ultrasonic compressional wave velocity data and azimuthal ultrasonic compressional wave energy data. A second embodiment uses azimuthal ultrasonic compressional wave velocity data and omni-directional sonic velocity data, with a comparison test or a curve fitting test. A third embodiment uses azimuthal ultrasonic compressional wave energy data.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.