Review of Parameter Estimation for Borehole Ultrasonic Echoes

This paper reviews the recent methods of ultrasonic echo signal parameter estimation in downhole instruments, the accurate measurement results of which guarantee the quality of dip calculation, hole shape analysis, and formation identification in Ultrasonic Borehole Imaging (UBI). Focusing on the time of arrival (TOA) and amplitudes inversion for ultrasonic pulse-echo signals, algorithms based on models, information criteria, and neural networks are respectively analyzed. Numerical and analytical experiments utilizing test well databases provide performance comparison and the relative merits of the aforementioned methods.