This document discusses different tools used to evaluate cement bonds around casing, including cement bond logs, ultrasonic logs, and isolation scanners. It explains how each tool works, such as using sound waves to evaluate cement thickness and bonding. The purpose of these tools is to assess zonal isolation and identify potential fluid migration paths to improve cementing operations and well integrity. Proper interpretation of cement bond logs requires understanding how the tools function and combining multiple measurements to fully evaluate cement quality and bonding.