Method and apparatus for acoustic detection of a fluid leak behind a casing of a borehole
US7219762B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 12, 2004 |
| Grant date | May 22, 2007 |
| Priority date | — |
| Expiry date | May 12, 2024 |
Classification
- Technology area (CPC E)Fixed Constructions
- CPC primaryE21B47/107
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An acoustic detection of a discrete acoustic signal allows to detect a leak behind a casing (23) of a borehole. An acoustic amplitude (AA) is sampled during a recording time period (24; 64) at a determined position along the tube. Time intervals (26; 66) are defined inside of the recording time period (24), and for each time interval (26) the measured acoustic amplitudes are processed to obtain respectively a corresponding power-frequency spectrum (261). A plurality of the power-frequency spectra are analyzed to identify the discrete acoustic signal by detecting time and frequency dependant changes of power. Preferably the processing involves a Fourier transform analysis. A power-frequency time plot is used to conveniently identify the discrete acoustic event.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.