In boreholes where formation shear velocity is lower than borehole tluid velocity neither refracted shear waves nor pseudo-Rayleigh waves can propagate. When frequency response of the sonde does not extend to low frequencies (e.g. 2 kHz) Stoneley waves are not excited efficiently. In such cases refracted P, leaking modes (PL) and tluid waves become dominant phases on a full waveform acoustic lo...

This study investigates the propagation of borehole Stoneley waves across heterogeneous and permeable structures. By modeling the structure as a zone intersecting the borehole, a simple one-dimensional theory is formulated to treat the interaction of the Stoneley wave with the structure. This is possible because the Stoneley wave is a guided wave, with no geometric spreading as it propagates al...

We present a boundary integral equation formulation for the problem of wave propagation in a borehole of irregular cross-section. The method consists in representing the wave field diffracted at the borehole-rock interface by the radiation from a distribution of surface sources applied along the borehole wall. The wave field in the borehole fluid and in the elastic rock are then expressed using...

An important application of borehole acoustic logging is the determination of formation permeability using Stoneley waves. Heterogeneous permeable structures, such as fractures, sand-shale sequences, etc., are commonly encountered in acoustic logging. The purpose of this study is to investigate the effects of the permeability heterogeneities on the borehole Stoneley wave propagation, We have st...

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...

The in situ permeability of a formation is obtained by the inversion of Stoneley wave phase velocity and attenuation, which are evaluated by applying the Extended Prony's method to the array sonic logging data. The Maximum Likelihood inversion is used together with logarithmic parameterization of the permeabilities. Formation shear wave velocity is also inverted for. This process is tested on b...

Stoneley waves in permeable boreholes are diagnostic of formation permeability because their propagation is affected by the dynamic fluid flow at the borehole wall. We characterize this flow using the concept of dynamic permeability. We examined the applicability of the dynamic permeability to porous media by applying it to a single fracture case and found that it agrees excellently with the fr...

The tube wave, or low-frequency manifestation of the Stoneley wave, has been modeled previously using the quasi-static approximation; I extend this method to include the effect of the formation matrix compressibility, which tends to marginally increase the tube-wave attenuation. Using the Biot theory of poroelasticity, I develop a fully dynamic description of the Stoneley wave. The dispersion r...

This paper describes a propagator matrix formulation for the problem of the Stoneley wave propagation in an irregular borehole. This is based on a simple one-dimensional theory that is possible for the low frequency Stoneley wave, because it is a guided wave with no geometrical spreading in the borehole. The borehole and the surrounding formation are modeled by multi-layers discretized along th...

This paper is concerned with the study of propagation of Stoneley waves at the interface of two dissimilar isotropic microstretch thermoelastic diffusion medium in the context of generalized theories of thermoelasticity. The dispersion equation of Stoneley waves is derived in the form of a determinant by using the boundary conditions. The dispersion curves giving the phase velocity and attenuat...