Numerical simulation of reflected wave characteristics in oil wells measured by Acoustic method

In order to analyze and identify the corrosion of the inner interface of the coupling, perforating and casing, or the collapse and depression of the casing, as well as the reflection form of the dynamic liquid level, the COMSOL finite element analysis software was used to carry out numerical simulation research on the above situation, and its response characteristics were obtained through calculation. In this paper, three-dimensional propagation characteristics of acoustic waves in the annulus of the oil jacket were studied using signal sources of different polarities. The results showed that when the polarity of the signal source was positive (negative), the coupling reflection signal was first positive (negative) and then negative (positive), and the perforation reflection signal was first negative and then positive (positive then negative). The waveform of the reflection signal in the case of corrosion or casing collapse was consistent with the waveform of the perforation reflection signal; the reflection signal of the moving surface was of the same polarity as the emission signal source. When the signal source was a positive-negative superimposed source, the conclusion obtained by applying the above-mentioned positive (negative) polarized signal source was based on the polarity of the first peak of the superposed source. The research results can provide strong support for the popularization and improvement of related theories, and correct reference standards for the performance verification of echo processing methods, as well as important theoretical basis for the correct identification of echo positions on the Dynamic fluid interface.