METHODS AND APPARATUS FOR CEMENT BOND EVALUATION THROUGH PRODUCTION TUBING

摘要

Various downhole logging tools and methods of using and making the same are disclosed. In one aspect a method evaluating cement bond quality in a well is provided. In a well with a particular casing/tubing configuration, waveforms of acoustic energy returning from the tubing and the casing with the tubing present are recorded (510). A frequency spectrum from the recorded waveforms is determined (525). Amplitudes of the returning acoustic energy at one or more preselected frequency(s) of interest of a range of frequencies at which the amplitudes are noticeably affected by cement bond quality for the particular casing/tubing configuration are determined (530). The determined amplitudes are compared with one or more baseline amplitudes to look for indications of cement bond quality (535). Other aspects involve time domain analysis.