casing, page-2

I found an interisting bit of information about cement logging.

This is done ultrasonically.

There are tools that can be put through tubing "SCMT operations provide a
clear advantage in workover wells
because there is no need to pull tubing
above the zone of interest for cement
evaluation." - see attached Schlumberger pdf link.

I would imagine that if they are so sure that it is cemented that they logged using one of the slim tools prior to trying to remove the string.

This is how they can be so confident the cementing operation is OK. Maybe they didn't have these tools in 12s day!

(Maybe the cement set in the time the logging was occurring, then they were unable to remove the tubing - this bit is conjecture).

http://www.slb.com/media/services/production/wellintegrity/cement_bond_logging_tools.pdf