Comparative analysis of methods to evaluate cement bond quality

It is shown that well logging may not adequately show whether cement is well bonded with the casing and formation. To achieve better accuracy in evaluation of cement bond quality it is recommended to perform cement-bond logging before and after the production string is run into the well and after cementing jobs are accomplished. Some modifications have been proposed for interpretation of gamma-gamma logging data using Scanning GR-Thickness Fault Detector. In particular it is suggested to introduce anisotropy factor for density measurements of cement sheath around the casing.