New completion techniques using expandable casing with swelling elastomers to seal the annulus, or just swelling elastomers used as packers are becoming available. Diagnostic services are required for these new completions such as evaluation of the annular seal, analogous to cement evaluation. Both conventional and new generation Wireline ultrasonic measurements have been used to characterize and possibly evaluate zonal isolation using swellable elastomers. So far, the following 360 degs circumferential measurements were studied: Ultrasonic radii, acoustic impedance (AI), as well as attenuation and third interface Echo (TIE) reflections from flexural wave data. Radii measurements show a "springback" effect, indicating that expansion against the formation has been achieved. Flexural attenuation has a much better dynamic range over the elastomer sections compared to the acoustic impedance measurements. Both measurements do not consistently distinguish rubber-backed casing with ordinary casing in our examples.
The TIE from the latest generation imaging tool tracking the external rubber interface, may provide the measurement the industry needs. First results look promising and further experiments to characterize the tool response are ongoing. The casing geometry of expanded liners was also studied.