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. A frequency spectrum from the recorded waveforms is determined. 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. The determined amplitudes are compared with one or more baseline amplitudes to look for indications of cement bond quality. Other aspects involve time domain analysis.