Preprint version Geotechnical Testing Journal, Volume 20, Issue 1, March 1, 1997, pages 17-28. Copyright © 1997 ASTM International. The definitive version is available at http://dx.doi.org/10.1520/GTJ11417J.
NOTE: At the time of publication, the author Nazli Yessiler was not yet affiliated with Cal Poly.
An ultrasonic testing method employing the pulse-echo inspection technique was developed to assess the integrity of annular seals surrounding casings (i.e., instrument tubes or well casings). This nondestructive testing method permits testing a seal from inside a casing without disturbing the casing, seal, or formation. Seals constructed with cement-based and bentonite-based sealants surrounding various types and sizes of casings can be evaluated using the method. An evaluation is conducted by sending and receiving ultrasonic waves using a single piezoelectric transducer and commercially available hardware (a pulser receiver and a waveform analyzer). A probe was designed and constructed for downhole testing. Differences in the ultrasonic responses of the materials in contact with a casing are analyzed to determine the presence of different materials (seal or defects filled with air or water in a seal) outside a casing.
Civil and Environmental Engineering