Processing array acoustic-logging data to image near-borehole geologic structures

Abstract

Imaging near-borehole structures using acoustic-logging data depends on the data-processing method used. We demonstrate that extracting the up- and downgoing reflections from the data and using those separately for the imaging can significantly improve the image quality. A parametric wave separation is first applied to array data to separate direct and reflection waves. In particular, we use a transmitter array gathered from successive source positions to extract the upgoing reflection. Reflection data can also be enhanced by stacking data along the reflection moveout in array using approximate structural dip information. Implementation of this method to acoustic-logging data processing improves imaging quality, making it possible to image near-borehole geologic structures using conventional array acoustic-logging. A potentially important application of drilling steering is using logging-while-drilling acoustic measurements.