Advanced High-Resolution Slowness Estimation for Acoustic Logging Data Based on Super-Virtual Interferometry

High-resolution geophysical exploration is crucial for accurately understanding underground structures. In acoustic well logging, conventional methods for enhancing vertical resolution often rely on coherence-based subarray techniques. However, due to the degradation of semblance over short arrays, the estimated acoustic slowness typically lacks accuracy for small aperture resolutions. In this article, an acoustic array processing method based on super-virtual interferometry (SVI) is presented, aiming to achieve high-resolution slowness profiles from borehole logging data. First, a subarray extension technique is proposed to enhance semblance. Second, we extend the SVI-based acoustic array processing methods, which can generate redundant information for semblance calculation from limited observations. The principles and workflow of the method are detailed, and numerical experiments are conducted to demonstrate its advantages over traditional processing approaches. Field data processing results indicate that the proposed methods provide high-accuracy measurements of slowness to the subfoot level, capturing intricate details of variations in formation slowness. Furthermore, field applications demonstrate the method's capability to process dipole flexural waves and effectively suppress extraction errors through dispersion, providing an alternative solution for the time-domain treatment of dispersive waves.