Abstract: Disclosed herein is a method for eccentricity correction. This method may dispose a downhole tool into a borehole. The downhole tool may comprise a measuring assembly that has at least one transducer, determining a beam pattern from the at least one transducer, determining a center of the measurement assembly in the borehole with the beam pattern, calculating a beam pattern factor with at least the beam pattern, calculating an angle factor with at least the beam pattern, calculating an eccentricity factor with at least the beam pattern factor and the angle factor, and creating an eccentricity corrected image with at least the eccentricity factor.

Abstract: Methods to perform through tubing cement evaluation using converted multipole resonance modes. A first acoustic transmission is emitted outward toward the cement such that a portion of the first acoustic transmission penetrates the cement. The receiver array detects the first acoustic response derived from the first acoustic transmission. The system then determines the multimode wellbore resonance based on the first acoustic response. In response to the first acoustic transmission penetrating the cement, a first mode of the multimode wellbore resonance is converted into a second mode different from the first mode. The receiver array detects a second acoustic response derived from the converted mode of the multimode wellbore resonance. The system determines the converted mode using the second acoustic response. A property of the cement is evaluated based on the multimode wellbore resonance and the converted mode.

Abstract: A method and system for generating an acoustic log. The method may comprise disposing an acoustic logging tool in a wellbore, broadcasting a shaped signal with the acoustic logging tool such that the shaped signal interacts with a boundary of a casing and a material, recording a result signal from the boundary with the acoustic logging tool, and decomposing the result signal into a resonance mode. The method may further comprise applying a bandpass filter to the resonance mode to form a filtered signal, selecting a baseline signal from the filtered signal, removing the baseline signal from the filtered signal, and generating a log from the filtered signal. The system may comprise an acoustic logging tool. The acoustic logging tool may comprise at least one transmitter and at least one receiver. The system may further comprise a conveyance and an information handling system communicatively connected to the acoustic logging tool.

Abstract: A system for leak detection. The system may comprise an acoustic logging tool that includes a hydrophone array with a plurality of hydrophones. The system may further include an information handling system communicatively connected to the acoustic logging tool and wherein the information handling system chooses three or more hydrophones from the plurality of hydrophones to operate during measurement operations.

Abstract: A logging tool for performing well logging activities in a geologic formation has one or more transmitters, one or more receivers, and a tool wave propagating factor which differs from a formation wave propagating factor. The one or more transmitters excite a tool wave and formation wave. The tool wave is reduced by the one or more transmitters transmitting an acoustic wave which causes the tool wave to be reduced. Additionally, or alternatively, the tool wave is reduced by generating an inverse estimate of the tool wave based on waveform data associated with the tool wave and formation wave received by each of the one or more receivers.

Abstract: A method and system for cement evaluation. The method may include disposing an acoustic logging tool into a pipe string that is disposed in a first casing of a wellbore, transmitting an acoustic wave at a first location within the wellbore from an acoustic source disposed on the acoustic logging tool, and recording one or more acoustic signals with one or more receivers on the acoustic logging tool at the first location. The method may further include performing a multichannel multimode dispersion analysis of the one or more acoustic signals, extracting one or more fluid modes propagating in the first casing from the dispersion analysis, extracting one or more pseudo-lamb waves propagating in the first casing from the dispersion analysis, extracting one or more pseudo-SH-plate waves propagating in the first casing from the dispersion analysis, and identifying a bonding condition between the first casing and a cement.

Abstract: Ringdown noise can be estimated and removed from a waveform captured by a downhole tool. Ringdown may be estimated by calculating a median of waveforms from a number of tool firings. The estimated ringdown may then be subtracted from a waveform currently being processed. The resulting waveform contains a more accurate representation of a true echo signal reflected from the borehole wall or formation. In some embodiments, the acoustic transducer's deterministic waveform may be learned by statistical analysis of other waveforms near in time to the presently measured waveform. In other embodiments, the deterministic waveform may be learned via previously acquired waveforms now stored in memory, or through predictive waveforms developed in laboratory testing conditions similar to those experienced downhole.

Abstract: In some embodiments, a method includes conveying a downhole tool in a tubing, positioned in a casing which forms an annulus between the casing and a wellbore formed in a subsurface formation, the downhole tool having a rotatable transmitter and a receiver array. The method includes performing the following until an acoustic transmission has been emitted for each of a number of defined azimuthal positions: rotating the rotatable transmitter to one of the number of defined azimuthal positions, emitting the acoustic transmission, and detecting, by the receiver array and without rotation of the downhole tool beyond a rotation threshold, an acoustic response of a number of acoustic responses that is derived from the acoustic transmission. The method further includes computationally rotating, by a processor and after detecting, data of each of the number of acoustic responses in a pre-determined direction to generate a computationally rotated multipole response.

Abstract: A method comprises conveying a downhole tool in a production tubing within a casing that is around a wall of a wellbore formed in a subsurface formation, wherein cement is placed in an annulus defined between the casing and the wall of the wellbore. The downhole tool includes at least one unipole receiver and a transmitter that comprises at least one of a unipole transmitter and a monopole transmitter. The transmitter and receiver are mounted on a rotatable portion of the downhole tool. The method includes performing the following operations at at least two azimuthal positions, emitting an acoustic transmission outward toward the cement and detecting an acoustic response that is in response to the acoustic transmission propagating through the production tubing and the casing and into the cement. The acoustic response includes casing extensional waves, casing non-extensional waves, and tubing waves. The method includes evaluating the cement based on the casing extensional waves.

Abstract: A hydrophone array tool as described herein is configured to locate leakages throughout a borehole with improved accuracy using acoustic beamforming techniques with acoustic velocity estimation. An acoustic beamforming processor generates an initial beamforming map and corresponding initial estimated leakage location using acoustic measurements throughout the borehole. The acoustic beamforming processor generates additional beamforming maps at the initial estimated leakage location, each additional beamforming map corresponding to an acoustic velocity within a range of anticipated acoustic velocities. An acoustic velocity estimator determines an acoustic velocity corresponding to a beamforming map with spatial statistics that indicate a most prominent leakage location. The acoustic beamforming processor updates the leakage location according to this beamforming map for improved accuracy.

Abstract: A method comprising: conveying a downhole tool in a tubing that is positioned in a casing that is positioned to form an annulus between the casing and a wall of a wellbore formed in a subsurface formation, wherein a cement with unknown bonding condition exists in the annulus, wherein the downhole tool includes at least one transmitter and a receiver array physically positioned in different azimuthal directions; emitting, from the at least one transmitter, a first and second acoustic transmissions in a first and second azimuthal directions; detecting, by the receiver array, a first acoustic response and a second acoustic response that is derived from the first and second acoustic transmissions, wherein the second azimuthal direction is orthogonal to the first azimuthal direction; determining a dipole wellbore resonance based on the first and acoustic responses; and evaluating a property of the cement based on the dipole wellbore resonance.

Abstract: The disclosure presents processes to determine the direction and magnitude of tubing eccentricity along the length of a tube inserted within a borehole. The tubing can be a wireline, a drill string, a drill pipe, or tubing capable of allowing fluid or other material to flow through it. As borehole operations proceed, the tubing can move toward the side of the borehole. This eccentricity can cause excess wear and tear on the tubing, on the casing of the borehole, or on the inner surface of the subterranean formation. The eccentricity can be measured using acoustic signals that are collected downhole covering the azimuthal angles 0° to 360° at a location in the borehole. The collected signals can be filtered, transformed, and analyzed to estimate the tubing eccentricity. Other processes and systems can use the results to obtain cement bond evaluations through tubing and to determine preventative or restorative actions.

Abstract: A method and system for cement evaluation. The method may include disposing an acoustic logging tool into a pipe string that is disposed in a first casing of a wellbore, transmitting an acoustic wave at a first location within the wellbore from an acoustic source disposed on the acoustic logging tool, and recording one or more acoustic signals with one or more receivers on the acoustic logging tool at the first location. The method may further include performing a multichannel multimode dispersion analysis of the one or more acoustic signals, extracting one or more fluid modes propagating in the first casing from the dispersion analysis, extracting one or more pseudo-lamb waves propagating in the first casing from the dispersion analysis, extracting one or more pseudo-SH-plate waves propagating in the first casing from the dispersion analysis, and identifying a bonding condition between the first casing and a cement.

Abstract: Methods, systems, and program products are disclosed for implementing acoustic logging and determining wellbore material characteristics. In some embodiments, a method may include determining a polar differential signal for each of one or more pairs of azimuthally offset acoustic measurements within a wellbore. A reference azimuth is identified based, at least in part, on comparing the polar differential signals to a modeled bonding differential signal within a target response window. The method further includes determining differences between an acoustic measurement at the reference azimuth and acoustic measurements at one or more other azimuths and determining a wellbore material condition based, at least in part, on the determined differences.

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: The present application discloses a nanometer self-locking bentonite film-forming agent, a method for preparing the same, and a film-forming drilling fluid.

Abstract: Methods and systems are disclosed for determining a material property transition within a wellbore. In some embodiments, a method includes determining a material transition profile for each of a plurality of test points within a linear measurement path including, for each test point, determining an acoustic response for a first location within the linear measurement path, and determining an acoustic response for a second location within the linear measurement path. The test point is between the first and second locations. The method further includes generating a material transition profile for the test point based, at least in part, on a difference between the acoustic response at the first location and the acoustic response at the second location.

Abstract: A sensor system may be used to measure characteristics of an object in a wellbore. The sensor system may include an ultrasonic transducer that generates an ultrasonic wave in a medium of the wellbore and detects a reflection signal of the ultrasonic wave off the object in the wellbore. The sensor system may also include a processing device and a memory device in which instructions are stored. The memory may include instructions that cause the processing device to receive the reflection signal from the ultrasonic transducer, and to truncate and preprocess the reflection signal to generate a truncated reflection signal. The instructions may also cause the processing device to apply time gain compensation to the truncated reflection signal and determine an echo wavelet from the time gain compensated signal representing an echo of the ultrasonic wave off of a wall of the wellbore.

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: Reducing casing wave effects on sonic logging data by positioning two or more receivers in a borehole in a subsurface formation; receiving, at two or more receivers in a borehole in a subsurface formation, a first signal associated with a first acoustic signal originating from a first transmitter position; receiving, at the two or more receivers, a second signal associated with a second acoustic signal originating from a second transmitter position; creating a dataset based on the first signal and the second signal; identifying casing wave signals in the dataset based at least in part on the second signal; calculating inverse-phase casing wave signals based at least in part on the casing wave signals and the second signal; and reducing effects of the casing wave signals on the dataset using the inverse-phase casing wave signals.