Abstract: Aspects of the subject technology relate to systems, methods, and computer-readable media for determining a quality of cementation and detecting a presence of microannulus formations within the cement bonded to the casing. An example method may include transmitting a first type of energy at a first angle to a surface of a casing of a wellbore. In some instances, the casing may be bonded to cement layer that is between the casing and a formation of the wellbore. Additionally, the example method may include receiving a first signal from the casing. Moreover, the example method may include determining a first attenuation of the first type of energy based on the first signal. Further, the example method may include determining whether microannulus formation is present between the casing and the cement layer based on one or more characteristics of the first attenuation.

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: An acoustic transducer includes a substrate element having a first side, and a second side opposite the first side. The acoustic transducer also includes first and second piezoelectric elements coupled to the first side, and third and fourth piezoelectric elements coupled to the second side. The first piezoelectric element has a first polarity, and the second piezoelectric element has a second polarity different than the first polarity. The third piezoelectric element has a third polarity, and the fourth piezoelectric element has a fourth polarity different than the third polarity.

Abstract: Systems and methods are provided for evaluation of the cement bonding condition in a wellbore based on borehole resonance mode using machine learning. An example method can include transforming the return signal into a resonance signal based on feature extraction of the return signal, determining a segment of the resonance signal in a time domain, and determining, via a machine learning model, a predicted borehole cement bonding based on the segment of the resonance signal. The example method can further include generating a bonding log based on the predicted borehole cement bonding.

Abstract: An anomaly in a cement layer of a wellbore can be identified by applying dimensionality reduction to acoustic data of the wellbore. For example, a computing system can receive the acoustic data from a downhole tool deployed downhole in the wellbore using a tool string positioned within a casing string of the wellbore. The computing system can decrease a number of dimensions associated with the acoustic data to generate a dimension-reduced dataset including a predetermined dimensionality. Subsequently, the computing system can analyze the dimension-reduced dataset to determine a likelihood of the anomaly being present in the cement layer of the wellbore. The computing system can output, via a user interface, a cement map based on the dimension-reduced dataset. The cement map can indicate a presence of the anomaly in the cement layer of the wellbore for use in adjusting a wellbore operation.

Abstract: A method for identifying guided waves in a measurement set. The method may comprise disposing an acoustic logging tool into a wellbore, performing a measurement operation with the acoustic logging too in the wellbore to form a data set which comprises one or more guided waves, measuring a speed of the one or more guided waves, and identifying a fluid phase interface using the speed of the one or more guided waves. The method may further comprise estimating an acoustic velocity of a wellbore fluid using a database and interpreting the fluid phase based at least in part on the acoustic velocity of the wellbore fluid.

Abstract: The present disclosure relates to determining a location of a noise source where the location includes azimuth information and determining cement-bond integrity. A downhole tool disposed in a borehole may comprise one or more receivers (such as a monopole receiver and any one or more of one or more multi-pole receivers) and in certain embodiments one or more transmitters that fire one or more shots may provide azimuthal estimate of the location of a noise source, a location of a leak in one or more layers of a casing, cement-bond integrity any combination thereof based, at least in part, on one or more measurements or data for received signals at any one or more receivers. Accurate and efficient identification of a leak or integrity of a cement-bond reduces overall inefficiencies and costs associated with a downhole operation.

Abstract: Some aspects provide for techniques for genotyping cells in a biological sample. In some embodiments, the techniques include: obtaining single cell DNA sequence (scDNA-seq) data for a plurality of droplets; and genotyping the cells using the scDNA-seq data, the genotyping comprising determining for each droplet, a genotype for a locus of a respective genome of at least one cell associated with the droplet, the determining comprising: identifying, from among the plurality of droplets, a first set of droplets associated with cells that are homozygous at the locus; identifying, from among the plurality of droplets not in the first set of droplets, a second set of droplets associated with more than two alleles at the locus; and identifying, from among the plurality of droplets not in the first or second sets of droplets, a third set of droplets associated with cells that are heterozygous at the locus.

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 for identifying a cement bond. The method may include disposing an acoustic logging tool into a tubing of a wellbore, wherein the wellbore further comprises casing cemented to a formation by a cement. The method may further include transmitting an acoustic signal into at least part of the tubing and at least part of the casing, measuring one or more signal waves from the at least part of the tubing and the at least part of the casing, and computing an array waveform from the one or more signal waves. Additionally, the method may include applying a beamforming algorithm to the array waveform to form a filtered signal, identifying eccentricity of the tubing within the casing using the filtered signal, and identifying a cement bond between the cement and the casing.

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 for forming an informed machine learning model. The method may include providing one or more inputs to an information handling system, adjusting the one or more inputs with one or more knowledge based features on the information handling system, and selecting one or more features from the one or more inputs by weighting informed features with the information handling system. The method may further include forming a training process from the one or more features selected by utilizing an informed loss function with the information handling system and forming an informed machine learning model that is used by the information handling system.

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: 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 at least one of a unipole 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 method of through tubing cement evaluation includes obtaining acoustic cement bond evaluation data relating to a property of a cement bond of a cased-borehole for each of a plurality of acoustic methods, wherein the acoustic cement bond evaluation data comprises a quality control (QC) value indicative of a confidence level of cement bonding condition, determining an eccentricity value of a tubing relative to a casing in the borehole, determining an output of each acoustic method by combining the eccentricity value and the acoustic cement evaluation data associated with each acoustic method, combining the output of each acoustic method to generate an optimized cement bonding index log of the cement bond, and employing the optimized cement bonding index log to provide an interpretation of an overall cement bonding condition.

Abstract: A method comprising: transmitting an acoustic signal into at least part of a conduit string, measuring a return signal from at least part of the conduit string, computing one or more amplitudes of a resonance signal from the return signal, and forming a depth-resonance amplitude log of the resonance signal with at least one of the one or more amplitudes of the resonance signal. Additionally, a system may be included and/or paired with the method. The system comprising: a transmitter configured to transmit an acoustic signal into at least part of a conduit string, a receiver configured to measuring a return signal from at least part of the conduit string, an information handling system configured for: computing one or more amplitudes of a resonance signal from the return signal, and forming a depth-resonance amplitude log of the resonance signal with at least one of the one or more amplitudes of the resonance signal.

Abstract: Aspects of the subject technology relate to systems, methods, and computer-readable media for synthesizing sonic logs for downhole environments. Data associated with a wellbore in a formation is accessed. A model configured to identify one or more characteristics associated with sound traveling through one or more formation is accessed. The data is applied to the model to predict a characteristics of the formation that is identifiable through sonic logging.

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: The invention relates to a slim sonic logging tool with multiple modules for borehole resonance mode and pitch-catch measurement, comprising a cylindrical housing, a monopole transmitter, a pair of cross-dipole transmitters and a ring of receivers disposed between the monopole transmitter and the pair of cross-dipole transmitters within the cylindrical housing, the ring of receivers, being axially around a circumference of the first cylindrical housing.

Abstract: Aspects of the subject technology relate to systems and methods for providing a TTCE dense acoustic array slim tool. An example through tubing cement evaluation (TTCE) tool comprising: a housing including a longitudinal axis; a transmitter being positioned within the housing, the transmitter being configured to operate in sonic and ultrasonic frequencies and being angled with respect to the longitudinal axis; a plurality of receivers being positioned within the housing, each of the plurality of receivers being isolated from the transmitter; one or more processors; and at least one computer-readable storage medium having stored therein instructions which, when executed by the one or more processors, cause the TTCE tool to: receive at least one of sonic and ultrasonic data from the plurality of receivers; and determine tubing or cement angular information based on the at least one of the sonic and ultrasonic data received from the plurality of receivers.