Dear Farid,
You normally cannot see through a second pipe, but... It depends on what you need. If it's only the TOC then I can think of two options, which depend more or less on your tubing and A annulus being full of water:
- You can run a Schlumberger Isolation Scanner, and send me the data. No guarantee and a bit of a research project, but I think I can get a passable evaluation of the outer casing. TOC should be easy.
- You can do a stationary heat dissipation test. Still a bit of a new concept, but may be easy to arrange and interpret. It does take time however, since it's not a continuous log. You may even do a neutron capture log, and qualitatively pick your cement top, but I have some doubts that the results will be clear enough.
At a deeper level, If I may ask, why do you need TOC? If it's needed to determine the free portion of casing, or whether you left a formation uncovered I see some use, but any method will struggle to see cement leakage pathways. In this case you could use indirect methods to spot the leak. If you have access to the B annulus it is reasonably easy to do leak fingerprinting and figuring out the source and type of pathway (channel, chimney or microannulus).
Best regards,
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Matteo Loizzo
Well integrity consultant
Berlin