Abstract: A downhole telemetry well system transmits data at a high rate inside a tubular pipe by encoding signals on a Stoneley wave. Telemetry devices for the Stoneley mode are implemented in short pipe joints inserted at various intervals between the tubulars. Each telemetry device includes Stoneley transducers, which may act as a transmitter, receiver, or repeater. The Stoneley telemetry devices transmit and receive the Stoneley waves making up the carrier of the signal. The Stoneley telemetry devices may be powered by on-board batteries or via some remote power source.

Abstract: A downhole telemetry well system transmits data at a high rate inside a tubular pipe by encoding signals on a Stoneley wave. Telemetry devices for the Stoneley mode are implemented in short pipe joints inserted at various intervals between the tubulars. Each telemetry device includes Stoneley transducers, which may act as a transmitter, receiver, or repeater. The Stoneley telemetry devices transmit and receive the Stoneley waves making up the carrier of the signal. The Stoneley telemetry devices may be powered by on-board batteries or via some remote power source.

Abstract: Methods and apparatus are provided for reducing and/or substantially eliminating sensitivity mismatch of acoustic receivers used with acoustic sources to determine acoustic properties of geologic formations as a logging tool traverses the formations. Methods are directed to detecting waveform arrival times at receivers, determining places in a well where arrival times of waves are substantially the same at a plurality of receivers, and estimating effective receiver sensitivities and equalization factors using Stoneley wave amplitudes and windowed deconvolution of Stoneley waves. Methods are further directed to correcting wave amplitudes using estimated effective receiver sensitivities and equalization factors for receivers.

Abstract: A system and method to determine an in-situ stress field based on borehole acoustic monopole and cross-dipole measurements. A radially polarized monopole shear-wave is generated in a borehole. It is then determined whether the shear-wave has split into two shear-waves. If it has, the difference in velocities between the two split shear-waves is used to determine the stress induced anisotropy around and near the borehole. The difference in velocities of cross-dipole shear-waves and the direction of the fast shear-wave are measured and used to determine the magnitude of the maximum shear stress and the maximum stress orientation of the geologic formation. Furthermore, a method of determining the stress-velocity coupling coefficients from laboratory measurements as well as through field measurement calibration is disclosed. The effect of borehole pressure on the field measurement calibration method of determining the stress-velocity coupling coefficients is taken into account.

Abstract: A method for determining the permeability of earth formations penetrated by a wellbore from acoustic signals measured by an acoustic wellbore logging instrument. The method includes separating components from the measured acoustic signals which represent Stoneley waves propagating through the earth formations. Signals representing Stoneley waves propagating through the same earth formations are synthesized. The separated acoustic signal components and the synthesized Stoneley wave signals are compared. The permeability is determined from differences between the synthesized Stoneley wave signals and the separated acoustic signal components. In a preferred embodiment, the step of calculating the permeability includes inversion processing a wave center frequency shift and a wave travel time delay with respect to the permeability of the earth formations.