Direct determination of formation shear wave travel time is impossible in "slow" formations where the shear wave velocity is lower than the borehole fluid (mud) velocity. However, the Stoneley waves in these formations are very sensitive to changes in formation shear wave properties and can be used to indirectly determine the formation shear velocity, In addition, the P wave packet is highly de...

Abstract—Stoneley waves are interface waves that propagate at the interface between two solid media. In this study, the dispersion characteristics and wave structures of Stoneley waves in elastic multilayered plates are displayed and investigated. With a perspective of bulk wave, a reasonable assumption of the potential function forms of the expansion wave and shear wave in nth layer medium is ...

A combination of borehole Stoneley waves from full waveform acoustic logs and direct shear wave logs was used to estimate formation permeability and shear wave velocity. Data sets used here were collected by ARea's array full waveform acoustic logging tool and shear wave logging tool. The Pand S-wave velocities of the formation are determined by threshold detection with cross-correlation correc...

The propagation of Stoneley waves in a fluid-filled borehole with a vertical fracture is investigated both theoretically and experimentally. The borehole propagation excites fluid motion in the fracture and the resulting fluid flow at the fracture opening perturbs the fluid-solid interface boundary condition at the borehole wall. By developing a boundary condition perturbation technique for the...

In recent years, borehole Stoneley wave amplitude and reflectivity have been used for estimating formation permeability based on the strong correlation between Stoneley wave attenuation, reflectivity and formation fluid conductivity. There are other factors, however, that may cause substantial Stoneley attenuation and reflection in a borehole environment. To make better use of Stoneley measurem...

A detailed study is carried out to investigate the effects of an acoustic logging tool on the propagation characteristics of Stoneley waves in both elastic and porous formations. In an elastic formation, the presence of the tool in the borehole reduces the Stoneley velocity and enhances the Stoneley wave excitation. When intrinsic attenuation due to formation and bore fluid anelasticity is pres...

The propagation of borehole Stoneley waves is strongly correlated with permeability of the formation. Previous studies primarily focused on the situation where the permeability is homogeneously distributed in the formation. In many in-situ situations, however, the permeability distribution of the formation is heterogeneous, due to effects such as a damaged zone around the borehole, random varia...

The analysis of Stoneley wave propagation in a fracture is essential for the identification and evaluation of fracture parameters from the borehole Stoneley wave. Also, it is important for many geophysics considerations, e.g. for tremor and long-period events observed in volcanoes and geothermal areas. In this paper, we investigate the guided waves propagation in a fluid layer lying between two...

To investigate the propagation of flexural waves in a borehole surrounded by an azimuthally anisotropic hard formation, we made an ultrasonic borehole model of Delabole slate with very strong anisotropy. The axial and azimuthal acoustic fields generated by a dipole source were measured in the fluid-filled borehole. The results show that there are three dominant wave modes: fast and slow flexura...

accurate permeability estimation has always been a concern in determining flow units, assigning appropriate capillary pressure andrelative permeability curves to reservoir rock types, geological modeling, and dynamic simulation.acoustic method can be used as analternative and effective tool for permeability determination. in this study, a four-step approach is proposed for permeability estimati...