Imaging method of surface wave velocity and attenuation coefficient

Imaging using the surface wave velocity dispersion curves received at the surface can detect underground mined-out areas and geological anomalies. The surface wave attenuation coefficient, which corresponds to the propagation velocity of surface waves, also varies with frequency. The curve formed by the attenuation coefficient exhibits peaks at frequencies where the wavenumber changes rapidly and can be imaged to reveal underground interfaces. Surface wave velocity reflects the changes in elastic parameters caused by stratal interfaces, while the attenuation coefficient reflects the leakage and conversion of surface wave energy at the interfaces. This paper presents measured downhole surface wave velocity and attenuation coefficient dispersion curves, demonstrating their correlation. Images of both are also provided for detecting stratal interfaces outside the wellbore.