METHODS FOR PROCESSING DISPERSIVE ACOUSTIC WAVEFORMS

摘要

This disclosure provides methods for processing dispersive acoustic waveforms. According to an embodiment, there is provided a method for processing acoustic data using DSTC processing that involves calculating dispersion sensitivity and implementing a dynamic processing frequency band to minimize or reduce the effects of model error. The method also involves determining sensitivity limits or "cut-offs" in the received acoustic data for various parameters, including tool presence in the borehole. Another embodiment involves an iterative process at each depth level wherein a first slowness is estimated using parameters assuming a homogenous isotropic model, and then semblance processing is iteratively repeated until a stop criteria is satisfied. Examples of stop criteria include a decreased error bar size, a minimized change in slowness between iterations, or a coherence (mean or peak) that decreases below a threshold.