Method for making cement impedance measurements with characterized transducer
US5146432A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 5, 1991 |
| Grant date | Sep 8, 1992 |
| Priority date | — |
| Expiry date | Aug 5, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N29/30
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
Methods for characterizing acoustic transducers and using a characterized acoustic transducer for measuring cement impedance of a cased well are disclosed. The method for characterizing the acoustic transducer generally comprises: arranging the acoustic transducer a predetermined distance from a calibration target of known thickness; transmitting a pulse from the acoustic transducer through a known medium and toward the calibration target and measuring a return signal received therefrom; and fitting, via minimization, a return signal calculation generated by a model of the return signal which has a limited number of parameters, to the received return signal to determine a value for at least one of the parameters and thereby characterize the transducer. The preferred parameters for characterization are the transducer radius and stand-off, such that the transducer may be characterized as having an effective stand-off and an effective radius. The method for measuring cement impedance behind the casing in a well utilizes the method for characterizing the transducer, where the calibration target is preferbly of the same radius and thickness as the casing of the well. Then, downhole, a p…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.