Abstract: A method for operation of an acoustic tool, having a plurality of acoustic sensors, may include receiving acoustic waves from an acoustic source located at a depth in a borehole. A selected location (e.g., central location) of the acoustic sensor array may be positioned substantially at the depth of the acoustic source based on a symmetricity of an upper and lower section of a frequency-wavenumber (f-k) transform pattern with respect to a selected wavenumber. A radial distance from the acoustic source to the acoustic tool may be determined based on a theoretical f-k transform pattern used as a mask to filter measured data in the f-k domain.

Abstract: Various embodiments include apparatus and methods to estimate formation mobility from Stoneley waveforms. An objective function can be generated that represents misfit between measured Stoneley pressure values and synthetic pressure values. A minimization process can be applied to the objective function to estimate formation mobility and intrinsic attenuation. Additional apparatus, systems, and methods are disclosed.

Abstract: A method for operation of an acoustic tool, having a plurality of acoustic sensors, may include receiving acoustic waves from an acoustic source located at a depth in a borehole. A selected location (e.g., central location) of the acoustic sensor array may be positioned substantially at the depth of the acoustic source based on a symmetricity of an upper and lower section of a frequency-wavenumber (f-k) transform pattern with respect to a selected wavenumber. A radial distance from the acoustic source to the acoustic tool may be determined based on a theoretical f-k transform pattern used as a mask to filter measured data in the f-k domain.

Abstract: Various embodiments include apparatus and methods to extract reflections from acoustic array data collected from a receiver array. A beam-former can be generated to detect a reflection wave in the presence of a direct wave identified from collected waveforms, where the beam-former can be correlated to receiver and depth for the array. The direct wave and the reflection wave can be separated to extract the reflection wave, where the separation is correlated to receiver and depth for the array. The extracted reflected wave can be used to image and/or analyze entities associated with the borehole. Additional apparatus, systems, and methods are disclosed.

Abstract: Various embodiments include apparatus and methods to operate to record a plurality of acoustic waveforms, to generate an objective function based on the plurality of acoustic waveforms, and to estimate a global minimum of the objective function. The plurality of acoustic waveforms can correspond to a plurality of acoustic dipole receivers azimuthally disposed around a tool to which the receivers are attached. Additional apparatus, systems, and methods are disclosed.

Abstract: Various embodiments include apparatus and methods to estimate formation mobility from Stoneley waveforms. An objective function can be generated that represents misfit between measured Stoneley pressure values and synthetic pressure values. A minimization process can be applied to the objective function to estimate formation mobility and intrinsic attenuation. Additional apparatus, systems, and methods are disclosed.

Abstract: In some embodiments, apparatus and systems, as well as methods, may operate to record a plurality of acoustic waveforms comprising cross-dipole waveforms and corresponding to acoustic waves received 5 at azimuthally orthogonal dipole receiver arrays surrounded by a geological formation, the waves being generated by azimuthally orthogonal dipole transmitter arrays. Further activity may include defining an objective function dependent on the cross-dipole waveforms, eigenvalues, an azimuth angle corresponding to an 10 orientation of the transmitter and receiver arrays; minimizing the objective function with respect to said angle and the set of auxiliary parameters; and determining at least one property of the geological formation based on the global minimum. Additional apparatus, systems, and methods are disclosed.

Abstract: Various embodiments include apparatus and methods to extract reflections from acoustic array data collected from a receiver array. A beam-former can be generated to detect a reflection wave in the presence of a direct wave identified from collected waveforms, where the beam-former can be correlated to receiver and depth for the array. The direct wave and the reflection wave can be separated to extract the reflection wave, where the separation is correlated to receiver and depth for the array. The extracted reflected wave can be used to image and/or analyze entities associated with the borehole. Additional apparatus, systems, and methods are disclosed.

Abstract: In some embodiments, apparatus and systems, as well as methods, may operate to record a plurality of acoustic waveforms corresponding to acoustic waves received at azimuthally orthogonal dipole receiver arrays surrounded by a geological formation, the waves being generated by azimuthally orthogonal transmitter arrays. Further activity may include analytically estimating a global minimum of a predefined objective function with respect to an azimuth angle at a point in an auxiliary parameter space associated with a set of auxiliary parameters, minimizing the objective function at the analytically estimated angle with respect to the auxiliary parameters, removing existing ambiguities associated with the fast and slow principal flexural wave axes, and determining at least one property of the geological formation based on the global minimum. Additional apparatus, systems, and methods are disclosed.

Abstract: Various embodiments include apparatus and methods to operate to record a plurality of acoustic waveforms, to generate an objective function based on the plurality of acoustic waveforms, and to estimate a global minimum of the objective function. The plurality of acoustic waveforms can correspond to a plurality of acoustic dipole receivers azimuthally disposed around a tool to which the receivers are attached. Additional apparatus, systems, and methods are disclosed.

Abstract: In some embodiments, apparatus and systems, as well as methods, may operate to record a plurality of acoustic waveforms corresponding to acoustic waves received at azimuthally orthogonal dipole receiver arrays surrounded by a geological formation, the waves being generated by azimuthally orthogonal transmitter arrays. Further activity may include analytically estimating a global minimum of a predefined objective function with respect to an azimuth angle at a point in an auxiliary parameter space associated with a set of auxiliary parameters, minimizing the objective function at the analytically estimated angle with respect to the auxiliary parameters, removing existing ambiguities associated with the fast and slow principal flexural wave axes, and determining at least one property of the geological formation based on the global minimum. Additional apparatus, systems, and methods are disclosed.

Abstract: In some embodiments, apparatus and systems, as well as methods, may operate to record a plurality of acoustic waveforms comprising cross-dipole waveforms and corresponding to acoustic waves received 5 at azimuthally orthogonal dipole receiver arrays surrounded by a geological formation, the waves being generated by azimuthally orthogonal dipole transmitter arrays. Further activity may include defining an objective function dependent on the cross-dipole waveforms, eigenvalues, an azimuth angle corresponding to an 10 orientation of the transmitter and receiver arrays; minimizing the objective function with respect to said angle and the set of auxiliary parameters; and determining at least one property of the geological formation based on the global minimum. Additional apparatus, systems, and methods are disclosed.