Abstract: The invention relates to a method of monitoring the interior of a pipeline (1) positioned in contact with a soil (S) below a water mass (E), comprising implementation of the following steps by data processing means (11): (a) for at least one position along said pipeline (1), obtaining acoustic data descriptive of at least one cross-section of said pipeline (1) at said position, acquired by a mobile acoustic acquisition device (20) in said water mass (E), (b) estimating by quantitative migration from said acoustic data an estimated relative impedance perturbation profile in at least said cross-section of said pipeline (1).

Abstract: The invention relates to methods for restoring well productivity and to devices for cleaning downhole mesh filters without disassembling water-lifting equipment. Well productivity is restored and maintained using an acoustic method based on generating an ultrasonic fluid flow directed at a filter to clean the pre-filter zone of clogging deposits by moving an acoustic emitter along the filter. The acoustic emitter is placed within the lower portion of a casing string, downstream of a submersible downhole pump, and is connected to a means for delivering thereof into the filter zone. The acoustic emitter device comprises an ultrasonic transducer block, which is disposed between two supporting plates and is connected therewith by a rotary unit and an electric motor.

Abstract: A system and method of obtaining a high SNR seismic while-drilling data and a robust velocity profile of a geological site having a main well and at least one uphole located in the vicinity of the main well, the seismic profile being obtained from seismic waves generated by a drilling device located at the main well. The method comprises deploying at least one distributed acoustic fiber optic cable vertically in the at least one uphole, at least a portion of the fiber optic cable being positioned at a depth exceeding a predetermined depth below the surface, receiving seismic data at recording station positioned on the at least one fiber optic cable at at least the predetermined depth, generating, at a processor a high SNR seismic while-drilling signal; yielding a reliable velocity profile from the seismic data received, and determining a presence of near surface hazards from the generated high SNR while drilling seismic data.

Abstract: A method for estimating an anomalous pore pressure value at depth level of a first discontinuous interface between a first geological formation and a second geological formation to be drilled by means of a drilling apparatus comprising at least one bit, where said method is implemented by means of a system comprising at least one electro-acoustic transducer (20) mounted with said bit, at least one memory for containing observable data and at least one control processor for processing observable data contained in said at least one memory, where said at least one processor controls transmitting a signal transmitted at a given frequency, said at least one electro-acoustic transducer receives a received signal that said at least one processor records in said at least one memory, comparing it with pre-loaded observable data in said at least one memory and estimating the value of the anomalous pore pressure of the first discontinuous interface.

Abstract: In at least one embodiment, a well inspection method and system enables transmission of an acoustic signal from a well inspection tool into a well structure and reception of return signals from the well structure at an array of receivers on the well inspection tool. The method and system enable performing of Short-Term Fourier Transform (STFT) on the return signals to generate spectrogram data that is used to determine short-term power spectra of the return signals. Time-dependent frequency response and location-dependent waveform propagation patterns are identified from the short-term power spectra. Cement bonding conditions is determined based on pattern matching using the time-dependent frequency response patterns and using the location-dependent waveform propagation patterns.

Abstract: A method for ultrafast compound plane wave imaging based on a broadband acoustic metamaterial: controlling the transmit-receive ultrasonic probe to emit an ultrasonic signal at a preset transmit frequency and a first preset transmit angle, the preset transmit frequency is equal to a response frequency of the acoustic metamaterial structure; controlling the transmit-receive ultrasonic probe to receive, at a preset receive frequency and separately at a first preset receive angle, a second preset receive angle, a third preset receive angle, echo signals reflected by a measured object, where the preset receive frequency is n times the preset transmit frequency, the first preset receive angle is equal to the first preset transmit angle, the second preset receive angle is smaller than the first preset transmit angle, the third preset receive angle is larger than the first preset transmit angle; using the echo signals to reconstruct an image of the measured object.

Abstract: A method for characterizing a hydraulic fracture in a subsurface formation includes inducing a pressure change in a borehole drilled through the subsurface formation. At least one of pressure and a time derivative of pressure is measured in the borehole for a selected length of time. At least one physical parameter of at least one fracture is determined using the measured pressure and/or the time derivative of pressure. A method for characterizing hydraulic fracturing rate uses microseismic event count measured through the borehole and its real-time implementation.

Abstract: A downhole tool having an acoustic transducer for downhole measurements. A backing is in contact with an inner surface of the transducer. A first structure is coupled to a first housing. A second structure is coupled to a second housing. A member includes first, second, and third portions. The first portion is coupled to the first structure. The second portion is coupled to the second structure. At least one of the first and second structures is coupled to the member and has a degree of freedom relative to the member. The third portion extends longitudinally through the backing between the first and second portions such that compressional forces on the first and second housings are transferred through the first and second structures and the backing. A canister contacts an outer surface of the transducer and exerts radial forces on the transducer when exposed to pressures higher than atmospheric pressure.

Abstract: The present disclosure relates to a method for pre-warning deformation of a casing pipe according to a change feature of the b-value of the hydraulic fracturing induced microseismicity. Based on number distribution and seismic magnitudes of hydraulic fracturing induced microseismic monitoring events, a b-value of microseismicity in a fracturing stage is calculated according to a Gutenberg-Richter relation describing frequency-seismic magnitude distribution in seismology, and whether fault activation occurs in a fracturing process is identified according to a change feature of the b-value. According to the method, a cumulative effect of fault activation in the hydraulic fracturing process is considered, and symptoms of fault activation in the fracturing process can be accurately identified, so as to pre-warn deformation of the casing pipe.

Abstract: The disclosure relates to a method and system for downhole processing of data, such as images, including using a set of downhole sensors to measure parameters relative to the borehole at a plurality of depths and azimuths and detecting predetermined features of the borehole, using a downhole processor, with a trained machine-learning model and extracting characterization data, characterizing the shape and position of the predetermined features that are transmitted to the surface. It also provides a method and system for providing an image of a geological formation at the surface including transmitting a first dataset to the surface that will be used for reconstructing an image at the surface, downhole processing of a second dataset to detect predetermined features and extract characterization data that are transmitted at the surface and displaying a combined image comprising the predetermined features overlaid on the first image.

Abstract: A sonic logging method is provided that transmits acoustic signals using a high order acoustic source and processes waveform data to identify a set of arrival events and time picks by automatic and/or manual methods. Ray tracing inversion is carried out for each arrival event over a number of possible raypath types that include at least one polarized shear raypath type to determine two-dimensional reflector positions and predicted inclination angles of the arrival event for the possible raypath types. One or more three-dimensional slowness-time coherence representations are generated for the arrival event and raypath type(s) and evaluated to determine azimuth, orientation and raypath type of a corresponding reflector. The method outputs a three-dimensional position and orientation for at least one reflector.

Abstract: The present disclosure provides novel systems and methods of locating downhole objects in a wellbore, the condition of casing within the wellbore, and characteristics of a subterranean formation. More specifically, data associated with a hydraulic impulse in fluid in the wellbore is used to determine a location of a downhole object. Data associated with the hydraulic impulse is collected and then processed in the frequency domain to identify the location of the downhole object. The downhole object may be a tool positioned within the wellbore or a fracture network that communicates with the wellbore by a perforation through wellbore casing. The system and method of the present disclosure can also be used to identify locations of unintended holes or perforations in casing and other tubulars.

Abstract: An outer tubular is imaged by a pad assembly disposed within an inner tubular inserted within the outer tubular. The pad assembly is in contact with the inner tubular, and includes an acoustic pressure source, a backing mounted to a side of the acoustic pressure source, and an intervening layer between the acoustic pressure source and inner tubular. Signals generated by the pad assembly propagate radially outward from the inner tubular and reflect from the outer tubular. The generated and reflected signals travel through a medium between the inner and outer tubulars. An estimate of the distance between the inner and outer tubulars is based on the time from generation of the signal to when the reflected signal is sensed.

Abstract: One embodiment includes receiving distributed acoustic sensing (DAS) data for responses associated with seismic excitations in an area of interest. The area of interest includes a sea surface, the water column, a seafloor, and a subseafloor. The seismic excitations are generated by at least one seismic source in the area of interest. The responses are detected by at least one fiber optic sensing apparatus configured for DAS that is in the water column, on the seafloor, in a wellbore drilled through the seafloor and into the subseafloor, or any combination thereof. The embodiment includes determining a function of speed of sound in water using the DAS data, and correcting a digital seismic image associated with the area of interest using the function of speed of sound in water to generate a corrected digital seismic image.

Abstract: Cement in a wellbore is evaluated by using cement evaluation tools to obtain ultrasonic image information and flexural wave image information. Flexural wave imager waveforms are applied to a trained machine learning system that predicts the presence or lack thereof of a clinging P as a function of depth and azimuth, while the ultrasonic imager impedance maps are applied to a trained machine learning system that identifies galaxy patterns for depths and azimuths, indicating the presence of a third interface echo (TIE) close to the casing. Locations of clinging Ps are compared to locations of galaxy patterns to identify when a TIE could cause a false clinging P determination. Where a disambiguated clinging P is found, contaminated cement is identified that may also locate the top of the cement in the annulus.

Abstract: Methods are disclosed for evaluating a material on a remote side of a partition separating first and second domains wherein flexural waves within the partition are received by spaced-apart ultrasonic receivers and processed to determine the velocity of the waves propagating into the second domain from a first receiver to a second receiver located more remote from the transmitter than the first receiver and whose separation from the first receiver is known. Comparison of a theoretical phase velocity with the measured phase velocity of the recorded waves allows determination as to whether the flexural wave is propagating through solid. This may be based on a measurable deviation between the two curves occurring at a critical frequency, which may be identified by a perturbation in a group velocity plot. Discrimination may also be based on the gradient of a straight line that best-fits the attention dispersion of the frequency spectrum.

Abstract: Systems and methods for detecting a gas kick within a wellbore are provided. The system includes a rotatable tool including one or more acceleration sensors and/or oscillators. The method includes rotating the rotatable tool in contact with fluid inside the wellbore and detecting changes in rotational velocity of the rotatable tool to detect the gas kick. In other aspects, the method includes detecting a change in density of the fluid within the wellbore by at least one or more pressure waves to determine the gas kick within the wellbore.

Abstract: Various downhole logging tools and methods of using and making the same are disclosed. In one aspect a method evaluating cement bond quality in a well is provided. In a well with a particular casing/tubing configuration, waveforms of acoustic energy returning from the tubing and the casing with the tubing present are recorded. A frequency spectrum from the recorded waveforms is determined. Amplitudes of the returning acoustic energy at one or more preselected frequency(s) of interest of a range of frequencies at which the amplitudes are noticeably affected by cement bond quality for the particular casing/tubing configuration are determined. The determined amplitudes are compared with one or more baseline amplitudes to look for indications of cement bond quality. Other aspects involve time domain analysis.

Abstract: A laser cutting apparatus conveyable within a casing lining at least a portion of a wellbore that extends into a subterranean formation. The laser cutting apparatus includes a housing, a deflector, a motor, a sensor, and a processing device. The deflector rotates relative to the housing to direct a laser beam to form a radial slot extending through the casing and into the subterranean formation. The motor rotates the deflector. The sensor generates information related to depth of the radial slot in real-time as the radial slot is formed by the laser beam. The processing device receives the information generated by the sensor and causes the motor to rotate the deflector based on the received information.

Abstract: A variable-frequency light source is configured to emit a light beam and modulate a frequency of the light beam. A fiber optic cable is attached to the variable frequency light source. The fiber optic cable is configured to receive the light beam at an inlet and pass the light beam to an exit. Multiple optical detectors are attached to the fiber optic cable. Each of the optical detectors is configured to detect a specified frequency of light that is backscattered through the fiber optic cable. An actuation mechanism is attached to the fiber optic cable. The actuation mechanism is configured to deform the fiber optic cable in response to a stimulus.

Abstract: An earth-boring tool includes a cutting element comprising a hard material and at least one of a signal generator configured to provide an electromagnetic or acoustic signal to an interface between a surface of the hard material and a surface of a subterranean formation, and a sensor configured to receive an electromagnetic or acoustic signal from the interface. A method of forming a wellbore includes rotating the earth-boring tool within a wellbore and cutting formation material with a cutting element, transmitting a signal through the cutting element to an interface between the cutting element and the formation material, and measuring a response received at a sensor. A cutting element includes a transmitter oriented and configured to dispense a signal to an interface between the cutting surface and a surface of a formation and a sensor oriented and configured to measure a signal from the interface.

Abstract: A workflow using techniques for improving signal-to-noise ratio and decreasing interferences for Low-Frequency Distributed Acoustic Sensing is described.

Abstract: The present disclosure provides methods and systems for analyzing cement integrity in a depth interval of a wellbore having a multiple string casing with an innermost annulus disposed inside at least one outer annulus. The method includes processing ultrasonic data obtained from ultrasonic measurements on the interval of the wellbore to determine properties of the innermost annulus. The method also includes processing sonic data obtained from sonic measurements on the interval of the wellbore to extract features of the sonic data. The features of the sonic data are input to a machine learning processing to determine properties of both the innermost annulus and the least one outer annulus. Additional processing of ultrasonic and sonic data can also be used to determine properties of both the innermost annulus and the least one outer annulus. These properties can be used to analyze cement integrity in the depth interval of the wellbore.

Abstract: Methods and apparatus for acoustic velocity well logging. Methods may include estimating a property of an earth formation, including estimating a depth-dependent lateral tectonic strain profile for the earth formation by generating a linear-to-linear transformation constrained to map a first value of a shear wave velocity parameter of the formation to an estimated minimum value of lateral tectonic strain in at least one direction corresponding to at least one principal horizontal stress of the formation, and map a second value of the shear wave velocity parameter of the formation to an estimated maximum value of lateral tectonic strain in the at least one direction, wherein the strain values may be estimated using closure pressure. The first value of the shear wave velocity parameter may be a minimum value of shear wave slowness and the second value of the shear wave velocity parameter is a maximum value of shear wave slowness.

Abstract: A method and system for inspecting cement downhole. The method may comprise inserting an inspection device inside a tubing. The inspection device may comprise a centralizing module as well as a transducer, an azimuthal receiver, and a telemetry module. The method may further comprise activating the transducer, wherein the transducer generates a low-frequency cylindrical acoustic wave with normal incidence, detecting the locations and strengths of resonances generated, and creating a graph with an information handling system for analysis.

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: Various apparatus or methods are arranged to operate a tool in a wellbore, where the tool has a number of acoustic sensors. Scanning images obtained by the tool sensors along the borehole can be combined to increase the contrast of leak location with respect to background noise. A sequence of beamformed images, generated from signals captured by the tool as it moves over a range of depths of the wellbore, can be acquired. Each beamformed image may overlap at least one other beamformed image of the sequence. The beamformed images can be processed and the processed beamformed images can be combined, forming a stitched image. Additional apparatus, systems, and methods operable in providing stitched images can operate in a variety of applications.

Abstract: Systems and methods for estimating orthorhombic anisotropy parameters of subsurface rock layers are provided. An initial three-dimensional (3D) model of layers in a subsurface formation is generated. Particular combinations of seismic source and receiver locations associated with a vertical seismic profile (VSP) survey of the formation are selected based on a simulation of seismic wave propagation through each layer of the initial 3D model. A global inversion is performed using data points selected from travel time data associated with the VSP survey in order to estimate different sets of anisotropy parameters for the layers of the initial 3D model, where the selected data points correspond to the selected source-receiver combinations. The initial 3D model is refined with an optimal set of anisotropy parameters selected from the estimated parameter sets. The refined 3D model is provided for seismic analysis and well planning operations to be performed for the subsurface formation.

Abstract: A method can include providing compressional and shear-wave slowness data for a homogeneous, anisotropic formation at deviated borehole angles greater than 40 degrees and less than 90 degrees as defined by a vertical transverse isotropy (VTI) symmetry axis; providing a relationship for normal and tangential compliances (e.g., BN and BT); and, based on the data and the relationship, outputting a model for calculating anisotropy parameter values (e.g., ?0, ?, .?) that characterize the homogeneous, anisotropic formation (e.g., along a borehole angle of 90 degrees). Various other apparatuses, systems, methods, etc., are also disclosed.

Abstract: A method can include receiving an estimated spatial location of a three-component receiver in a borehole; receiving a plurality of spatial locations of sources of seismic energy; receiving incident angles for the three-component receiver at the estimated spatial location for the plurality of spatial locations of the sources of seismic energy; computing orientations for the three-component receiver based at least in part on the incident angles; minimizing an error function for the orientations; and, based at least in part on the minimizing, determining one or more deviation survey parameter values that specify at least a portion of a trajectory for the borehole.

Abstract: Certain embodiments disclosed herein include a circuit for generating modulated backscattered sensory data. The circuit includes a sensor configured to produce sensory data in a format of a bitstream; a waveformer configured to generate a waveform signal (m(t)) compliant with a wireless protocol; a backscatter mixer configured to modulate each bit in the bitstream using the waveform signal; and a wakeup trigger configured to trigger the backscatter mixer in response to a reception of a packet from a first wireless device, wherein the modulated backscattered bitstream is being transmitted to a second wireless device.

Abstract: A downhole installation includes a first pipe layer, a second pipe layer about the first pipe layer, an annulus between the first and second pipe layers, and a geological formation outside of the second pipe layer. A method for evaluating the downhole installation includes: exciting a flexural wave in the first pipe layer using an angled acoustic transmitter; receiving third interface echo data using a plurality of angled acoustic receivers at different locations along the longitudinal extent of the pipe layers; generating acoustic resonance across the thickness of the first and second pipe layers by use of full waveform excitation; receiving the acoustic response wave field generated by the full waveform; identifying a suitable component of the acoustic response wave field; determining if the material outside the second pipe layer is fluid or solid; and analyzing the third interface echo data to thereby evaluate material conditions in the annulus.

Abstract: A distributed acoustic sensing cable including an optical fiber waveguide configured to provide light signal transmission and an acoustic device coupled to the optical fiber waveguide and configured to provide acoustic signal transmission. The acoustic device includes a polymer composite having reinforced fibers embedded therein. The polymer composite having acoustic waveguides for attenuating undesirable acoustic waves propagating along the distributed acoustic sensing cable and optical fibers embedded within the polymer composite that extend along an axial length of the acoustic device that facilitate the light signal transmission.

Abstract: A method of determining properties of a wellbore in a formation includes obtaining from the acoustic logging tool, acoustic data comprising an acoustic wave reflected from the casing, the annular fill material, one or more interfaces between any of the mud, the casing, and the annular fill material, or combinations thereof. The method includes normalizing the acoustic wave in a frequency domain, resulting in a specular spectrum and removing spectral noise outside a region of interest in the specular spectrum. The method includes shaping the specular spectrum around a resonance frequency, converting the shaped specular spectrum into a time domain, resulting in a renormalized waveform, and subtracting from the renormalized waveform one or more of a specular noise, second interface echoes, resulting in a third interface echo signal.

Abstract: A logging sensor or tool including a structural component, a non-structural component, and a composite disposed between the structural component and the non-structural component. The composite may contain a metallic foam having pores and an elastomeric material deposited in the pores. The elastomeric material may include an elastomer and a plurality of metallic shield particles. A logging system and to a wireline system containing such a logging sensor or tool.

Abstract: The present disclosure includes a method for monitoring a subsurface formation including disposing an antenna in a horizontal wellbore, the antenna including a plurality of piezoelectric modules. A voltage signal is applied to at least one of the piezoelectric modules to cause the at least one piezoelectric modules to emit seismic energy into the subsurface formation. A resulting signal is received at a receiver. A property of the subsurface formation is determined based, at least in part, on the resulting signal.

Abstract: Systems, methods, and computer-readable storage devices for determining a location of an acoustic source outside of a borehole. The method relates to indicating a radial distance to the borehole, an offset along the borehole, and an azimuthal position around the borehole, of the acoustic source. The method includes receiving acoustic signals from respective acoustic sensors spaced along a tool lowered within the borehole. Using the acoustic signals and a borehole model, stacked energies are calculated for different radial distances from the borehole. At least one of the stacked energies is translated to an indication of a radial distance of the acoustic source from the borehole. The stacked energy for a radial distance is computed by offsetting the acoustic data signals in time in accordance the borehole model, summing the offset acoustic data signals to produce a stacked signal, and evaluating energy of the stacked signal over a time window.

Abstract: Apparatus, systems, and methods may operate to receive radiated energy as scattered energy after the radiated energy interacts with a geologic formation, wherein the scattered energy is received at a sub-surface multi-channel sensor array that operates to transform the scattered energy into received signals, and wherein the radiated energy is provided by a sub-surface source of elastic energy; and to identify discontinuous features in the geologic formation by interferometric comparison of the received signals as elastic signals and/or electromagnetic signals among some sensors in the sensor array, or by time-reversal propagation of the received signals as elastic and/or electromagnetic signals in a numeric model of a volume of the geologic formation. Additional apparatus, systems, and methods are disclosed.

Abstract: In some embodiments, apparatus and systems, as well as method and articles, may operate to launch acoustic waves along a first acoustic path length from an acoustic transducer toward an axis of rotation, to impinge on a first front surface of a target substantially fixed with respect to the axis, and to receive a reflection of the acoustic waves from the first front surface at the acoustic transducer. After rotating the acoustic transducer about the axis along a substantially circular path, additional activities may include launching acoustic waves along a second acoustic path length, different from the first acoustic path length, from the acoustic transducer toward the axis to impinge on a second front surface of the target, and receiving a reflection of the acoustic waves from the second front surface at the acoustic transducer. Additional apparatus, systems, and methods are disclosed.

Abstract: A method of detecting an edge of a geological characteristic in a borehole comprises, in respect of an image log of a length of a borehole, carrying out the steps of a gradient-based edge detection method, a phase congruence-based edge detection method or a combination of such methods as preliminary, pre-processing stages. Subsequent steps of the method may include operating a relatively computationally simple process to identify sinusoids among detected edge features; and a relatively computationally complex process for parameterizing the thus-identified sinusoids.

Abstract: A distributed acoustic wave detection system and method is provided. The system may include a fiber optic cable deployed in a well and configured to react to pressure changes resulting from a propagating acoustic wave and an optical source configured to launch interrogating pulses into the fiber optic cable. In addition, the system may include a receiver configured to detect coherent Rayleigh noise produced in response to the interrogating pulses. The CRN signal may be used to track the propagation of the acoustic waves in the well. Such capability allows the location of the cement sheath, as well as measuring the bonding of cement to at least a casing string at least partially surrounded by a cement sheath.

Abstract: Acoustic logging systems and methods are provided with multi-mode inversion for at least vertical shear slowness and shear anisotropy. At least some method embodiments acquire waveforms for multiple acoustic wave modes as a function of tool position in a borehole, derive position-dependent mode dispersion curves from the waveforms, match the derived dispersion curves with parameterized dispersion curves to determine a vertical shear slowness and a shear anisotropy as a function of position, and displaying a borehole log that represents at least one of the vertical shear slowness and the shear anisotropy as a function of position. The objective function employed for the inversion is evaluated across multiple wave propagation modes and mud slownesses and may employ an adaptive, frequency-dependent weighting based on distance between the derived dispersion curves and the parameterized dispersion curves.

Abstract: A method and apparatus for detecting a kick in a wellbore using acoustic transducers. In one embodiment, a system for detecting a kick in a wellbore includes a drill string having a plurality of sections of drill pipes and a plurality of kick detection subs disposed between the sections of drill pipes. Each of the kick detection subs includes an acoustic transducer and kick detection circuitry coupled to the acoustic transducer. The kick detection circuitry is configured to detect gas bubbles in the wellbore based on acoustic signals received by the acoustic transducer. The kick detection circuitry is also configured to determine whether a kick is present in the wellbore based on the detected gas bubbles. The kick detection circuitry is further configured to transmit information indicating whether a kick is present to the surface.

Abstract: A method of logging a perforation tunnel and associated features of the perforation tunnel can include the following features. A logging device including an ultrasonic transducer is located downhole into a well. The well has a casing. The ultrasonic transducer has a focal point that is a distance from the ultrasonic transducer so as to be behind the inner face of the casing. An ultrasonic signal is projected from the ultrasonic transducer. A reflection of the ultrasonic signal is reflected from an internal portion of the perforation tunnel, the perforation tunnel extending through the casing and into formation. A transit time is measured between transmission and reception of the ultrasonic signal. A position of the ultrasonic transducer corresponding to the ultrasonic transmission and reception of the reflected signal is determined.

Abstract: A cement bond logging method for wells containing heavy mud and cement is provided. Acoustic logging tool data from a well having material in the annular space between the casing and the formation is analyzed to map relationships between waveform amplitude, acoustic impedance, and impedance derivative of the material. Map zones representing fully bonded well regions and partially bonded well regions are identified. An image is generated from the log data corresponding to the identified map zones. A cement bond logging system including a memory having cement bond logging software and a processor coupled to the memory to execute the software is also provided.

Abstract: A method of determining properties of a bonding material disposed outside of a casing in a borehole includes at least two of the following three pairs of operations: (1) inducing an acoustic wave in the casing, and measuring attenuation of the acoustic wave, by pulse-echo or other cement bond logging measurement; (2) inducing an SH wave in the casing, and measuring attenuation of the SH wave; and (3) inducing a Lamb wave in the casing, and measuring attenuation of the Lamb wave. (2) and/or (3) may be performed by an electromagnetic acoustic transducer. The method further includes determining the shear velocity or shear impedance and the compressional velocity or compressional impedance of the bonding material based on appropriate ones of the measurements. The bonding material may be cement.

Abstract: A method for determining a volume of a fracture network includes detecting seismic signals deployed over an area of the subsurface during pumping of fracturing fluid into at least one wellbore drilled through the area. A hypocenter of each fracture induced by the pumping is determined using the seismic signals. A facture network and associated fracture volume is determined using the determined hypocenters and seismic moments determined from the detected seismic signals. A maximum value of a scaling factor is determined based on a subset of the hypocenters having a highest cumulative seismic moments. The scaling factor is determined by relating a pumped volume of the fracturing fluid with respect to the determined fracture volume. Dimensions of each fracture are scaled using the maximum value of the scaling factor. The fracture volumes are recalculated using the scaled dimensions.

Abstract: Casing signals generated by an EMAT in a borehole are processed using at least two orthogonal band-limited filters. The band-limited filters may include Gaussian or Cauchy Wavelet filters. By using the Hilbert transform, an envelope of the filtered signals is determined and amplitudes and arrival times of individual arrivals are estimated. These can be used to estimate casing and cement properties.

Abstract: The present disclosure is related to apparatuses and methods for estimating borehole parameters using a plurality of reflections caused by a plurality of acoustic pulses. The reflections may overlap each other and/or the acoustic pulses. The methods may include estimating an envelope of the received acoustic signal at the at least one element of the array of transducers; and estimating at least one arrival time of at least one of the plurality of overlapping events from the envelope of the received acoustic signals, the arrival times being characteristic of the geometry of the borehole. The method may also include imaging the borehole wall. The apparatus may include an array of transducers on a rotatable transducer assembly with at least one element on the array configured to generate a plurality of acoustic pulses and receive reflections and a processor configured to perform the method.

Abstract: A method, system and apparatus for testing properties of a rock formation surrounding a wellbore in situ. The apparatus includes a tool body, one or more indenters, and one or more acoustic sensors. The body includes an outer surface that defines one or more cavities therein. Each cavity extends into the body. Each indenter is positioned within a corresponding cavity and is positionable into an operating position and a non-operating position. The acoustic sensor is positioned within the cavity and adjacent to the indenter. The indenter is positioned at least partially beyond the outer surface when in the operating position. The acoustic sensor senses one or more acoustic events occurring when the indenter is in the operating position. The apparatus is inserted into the wellbore. Once inserted, the indenter applies a load onto the rock formation causing cracking and the sensor receives the generated acoustic transmissions. The transmissions are analyzed.