Abstract: Disclosed is a system and method for calculating a formation shear-wave slowness. The system includes a borehole sonic logging tool and an information handling system. The borehole sonic logging tool may comprise a transmitter comprising one or more elements disposed at one or more radial distances from an axis of the borehole sonic logging tool and the transmitter is configured to transmit a first mode into a borehole. The sonic logging tool may further include one or more receivers disposed at a second radial distance from the axis of the borehole sonic logging tool and are configured to detect a second mode that one or more lobes than is a higher order than the first mode. A method may comprise broadcasting the first mode into the borehole, recording the second mode from the borehole with the one or more receivers, and calculating the formation shear-wave slowness from the second mode.

Abstract: An apparatus, method, and system for determining body wave slowness from guided borehole waves. The method includes selecting a target axial resolution based on the size of a receiver array, obtaining a plurality of waveform data sets corresponding to a target formation zone and each acquired at a different shot position, computing a slowness-frequency 2D dispersion semblance map for each waveform data set, stacking the slowness-frequency 2D dispersion semblance maps to generate a stacked 2D semblance map, and determining a body wave slowness from the extracted dispersion curve. The method may also include generating a self-adaptive weighting function based on a dispersion model and the extracted dispersion curve, fitting the weighted dispersion curve and the dispersion model to determine a body wave slowness that minimizes the misfit between the weighted dispersion curve and the dispersion model. The method can be applied to both frequency-domain and time-domain processing.

Abstract: The disclosure is directed to waveform processing methods for collected sonic logging data. The data can be collected from various types of well systems. The methods utilize an amplitude analysis, utilizing the collected data, to build an adaptive data mask. The adaptive data mask can then be applied to a semblance analysis of the collected data to suppress or partially suppress alias data elements. A threshold parameter can be utilized to eliminate intensity values that do not satisfy the threshold criteria. The adaptive data mask can utilize amplitude or instantaneous amplitude analysis. Also, disclosed is a computer program product capable of executing the methods and algorithms described herein. A waveform processing system is disclosed that can perform the methods and algorithms as described herein.

Abstract: Disclosed are systems and methods for selecting modes and frequencies of interest in a slowness-frequency map of sonic logging information. These include measuring, by a sonic logging tool, sonic data within a borehole, determining a frequency range for a selected mode of the sonic data, determining a slowness range for the selected mode of the sonic data, applying the frequency range and the slowness range to the sonic data to select a subset of data from the sonic data, processing the selected subset of data.

Abstract: A borehole sonic logging tool and method for imaging. The borehole sonic logging tool may comprise a transmitter configured to transmit a sonic waveform into a formation, wherein the transmitter is a dipole, and a receiver configured to record a reflected wave as waveform data, wherein the receiver is a quadrupole. A method may comprise disposing a downhole tool into a borehole, selecting a frequency range for the transmitter to a horizontally-polarized shear formation body wave, broadcasting the sonic waveform as the horizontally-polarized shear formation body wave into the formation penetrated by the borehole with the transmitter, recording a reflected wave on the receiver as waveform data, wherein the reflected wave is the horizontally-polarized shear formation body wave reflected from a reflector, and processing the waveform data with an information handling system.

Abstract: A method for enhanced dispersion analysis begins with obtaining a plurality of measured waveforms, for example from two or more receivers of an acoustic logging tool placed in a borehole. The measured waveforms are divided into common gathers, and waveforms of each common gather are enhanced. The enhancement begins by calculating a travel time curve for a selected target mode of the common gather waveforms. Using the travel time curve, waveforms of the selected target mode are aligned to have zero apparent slowness. The aligned waveforms are filtered to suppress non-target mode waves. The aligned waveforms are then enhanced, and used to generate an enhanced dispersion curve of the selected target mode.

Abstract: A method and system for locating a reflector in a formation. The method may comprise broadcasting a sonic waveform as a shear formation body wave or a compressional formation body wave into the formation, recording a reflected wave from a reflector with the one or more receivers as dipole data by the dipole receiver and quadrupole data by the quadrupole receiver, and processing the dipole data and the quadrupole data with an information handling system to determine a location of the reflector from the borehole sonic logging tool. The system may comprise a borehole sonic logging tool and an information handling system. The borehole sonic logging tool may comprise one or more transmitters configured to transmit a sonic waveform into a formation and one or more receivers configured to record a reflected wave as a dipole receiver for dipole data and a quadrupole receiver for quadrupole data.

Abstract: A method and system for pad alignment may comprise disposing a downhole tool into a borehole, taking a measurement with the electrode with at least one operating frequency, correcting the measurement to account for local formation dip, constructing a window with a predetermined size H, identifying a number of adaptive filters to be utilized, extracting one or more frequency components from the measurement with the adaptive filters, identifying a semblance value of a reference dataset and a target dataset, assembling the semblance values for the reference dataset and the target dataset, identifying the semblance values of the reference dataset and target datasets over the range of relative pad shifts, identifying a pad shift, and forming one or more images of the pad shirt or the semblance of the reference dataset and target data set. The system may comprise a mandrel, one or more pads, and electrodes.

Abstract: An apparatus includes a mechanical wave source; a set of mechanical wave sensors in a borehole to provide subsurface wave measurements based on formation waves from the mechanical wave source, and a processor. The apparatus also includes a machine-readable medium having program code to acquire the subsurface wave measurements, select a first set of tool wave measurements based on the subsurface wave measurements, and generate a set of filtered subsurface wave measurements by filtering the subsurface wave measurements based on the first set of tool wave measurements. The program code also includes instructions to generate a time-domain semblance map based on the set of filtered subsurface wave measurements, wherein the time-domain semblance map includes an initial set of compression wave peaks, determine a selected qualified compression wave peak based on a semblance value in the time-domain semblance map, and determine a compression wave slowness based on the selected qualified compression wave peak.

Abstract: A method for identifying a leak for dynamic logging may comprise estimating a Stoneley wave slowness, separating a Stoneley wave into an up-going Stoneley wave and a down-going Stoneley wave, estimating an amplitude of the up-going Stoneley wave and the down-going Stoneley wave, identifying a difference between the amplitude of the up-going Stoneley wave and the down-going Stoneley wave, forming an amplitude summation curve or an amplitude difference curve, and identifying a location of the leak.

Abstract: A method for removing a guided wave noise in a time-domain may include recording one or more acoustic signals with one or more receivers at a first location, wherein the one or more acoustic signals are raw data. The method may further include determining a slowness range, estimating a downward guided wave noise by stacking the one or more acoustic signals based at least in part on a positive slowness, estimating an upward guided wave noise by stacking the one or more acoustic signals based at least in part on a negative slowness, and identifying a dominant direction of propagation. The method may further include identifying a slowness from a highest stacked amplitude for the dominant direction of propagation, estimating a downward guided wave noise with the slowness, estimating an upward guided wave noise with the slowness, and subtracting the downward guided wave noise and the upward guided wave noise.

Abstract: A method for determining mud properties may comprise taking multi-frequency measurement data with a downhole tool, selecting an injector electrode from the one or more injector electrodes for the multi-frequency measurement data, selecting data from the multi-frequency measurement data with low resistivity or a large standoff, creating a forward model based at least partially on the selected data by making initial guesses of model parameters for one or more mud properties, performing a cost function minimization with the forward model, identifying from the cost function minimization if a misfit is above or below a threshold, and identifying the one or more mud properties based at least in part on the cost function minimization. A system may comprise a downhole tool including a mandrel, one or more arms, one or more pads, and one or more injector electrodes. The system may further include an information handling system.

Abstract: A method may comprise: disposing an acoustic logging tool in a wellbore, wherein the acoustic logging tool comprises a transmitter and a receiver; emitting a flexural wave from the transmitter; recording a four component dipole waveform with the receiver, wherein the four component dipole waveform comprises XX, XY, YX, and YY components; rotating the four component dipole waveform using Alford rotation to produce rotated waveform components, wherein the rotated waveform components comprise XX?, XY?, YX?, and YY? components; comparing a travel time of XX? and YY? components to identify a fast wave and a slow wave from the rotated waveform components; processing the fast wave and the slow wave using high-resolution data-driven processing to obtain a fast wave flexural dispersion curve and a slow wave flexural dispersion curve; determining a frequency dependent anisotropy curve using the fast wave flexural dispersion curve and the slow wave flexural dispersion curve; and determining a low-resolution shear anisot

Abstract: A method and system for pad alignment may comprise disposing a downhole tool into a borehole, taking a measurement with the electrode with at least one operating frequency, correcting the measurement to account for local formation dip, constructing a window with a predetermined size H, identifying a number of adaptive filters to be utilized, extracting one or more frequency components from the measurement with the adaptive filters, identifying a semblance value of a reference dataset and a target dataset, assembling the semblance values for the reference dataset and the target dataset, identifying the semblance values of the reference dataset and target datasets over the range of relative pad shifts, identifying a pad shift, and forming one or more images of the pad shirt or the semblance of the reference dataset and target data set. The system may comprise a mandrel, one or more pads, and electrodes.

Abstract: An apparatus and system for deploying an acoustic sensor are disclosed. In some embodiments, an acoustic sensor includes a transducer comprising a piezoelectric material layer having a front side from which the transducer is configured to transmit acoustic sensing signals and an opposing back side. A backing material layer comprising an acoustic damping material is coupled at a front side to the back side of the piezoelectric material layer. An acoustic reflector such as may comprise a cavity containing gaseous or liquid fluid is disposed between the front side and a back side of the backing material layer.

Abstract: Techniques for calculating and visually presenting multiple acoustic modes that have different formation slowness are disclosed herein. The techniques include methods for receiving time-domain waveforms from adjacent formations in a borehole, processing each of the time-domain waveforms to generate frequency-domain spectrums, selecting frequency and slowness values, and predicting travel time of a mode associated with the slowness value. In some aspects, the method further includes steps for calculating a semblance difference of the frequency-domain spectrums based on the frequency value, the slowness value and the predicted travel time. Systems and computer-readable media are also provided.

Abstract: Techniques for estimating and visually presenting formation slowness are disclosed herein. The techniques include receiving acoustic signal responses from adjacent formations at a plurality of depths in a borehole environment, mapping a distribution of the acoustic signal responses at each depth according to slowness and a frequency values, determining at least one confidence interval to define a coherence threshold for the distribution of the acoustic signal responses at each depth, generating a variable density log for each depth based on the distribution of acoustic signals responses that satisfy the confidence interval for one or more frequency ranges, determining a formation slowness value for each depth based on the variable density log for the each depth, and presenting a semblance map that includes a slowness axis, a depth axis, the formation slowness value for each depth, and at least a portion of the distribution of acoustic signal responses at each depth.

Abstract: The disclosure is directed to waveform processing methods for collected sonic logging data. The data can be collected from various types of well systems. The methods utilize an amplitude analysis, utilizing the collected data, to build an adaptive data mask. The adaptive data mask can then be applied to a semblance analysis of the collected data to suppress or partially suppress alias data elements. A threshold parameter can be utilized to eliminate intensity values that do not satisfy the threshold criteria. The adaptive data mask can utilize amplitude or instantaneous amplitude analysis. Also, disclosed is a computer program product capable of executing the methods and algorithms described herein. A waveform processing system is disclosed that can perform the methods and algorithms as described herein.

Abstract: A method and system for producing a Quasi-Static Stoneley Slowness log. The method for producing a Quasi-Static Stoneley Slowness log may comprise recording a pressure wave at a receiver; determining a slowness-frequency range with an information handling system from the pressure wave, processing a frequency-domain semblance, extracting a Stoneley Dispersion, minimizing a misfit between theoretical and the Stoneley Dispersion, and identifying Quasi-Static Stoneley slowness from the Stoneley Dispersion. The well measurement system for producing an Quasi-Static Stoneley Slowness log and shear slowness anisotropy may comprise a downhole tool, a vehicle, and an information handling system.

Abstract: An acoustic logging system identifies hydrocarbon formation types by a real-time model-constrained mud wave slowness determination method using borehole guided waves. The system also combines data processing from different acoustic waveform processing techniques using an information sharing procedure, for example, using monopole source data and dipole source data, to further improve the processing results and to achieve more stable and reliable real-time shear slowness answers.